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Digital volume control question....
A week or two ago I bought a little cheapo ss amplifier from Argos for
fun/summer/curiosity/all day long radio, MP3s &c. and wuz so taken with it I bought a couple more (similarly cheap) components from the same range to go with it: http://www.apah69.dsl.pipex.com/show/outbreak.JPG (OK, I admit it - I was driven by the 3-way, multi-purpose remote control!! :-) Anyway, the clarity I'm getting from this little bugger from any number of different sources is quite exceptional and I'm wondering if the 'digital volume control' has anything to do with it? I know the speakers (firewood horns - Pinkies) are 'on song' now and will be contributing mostly to the sound quality and I am convinced that normal (carbon wiper) volume pots do the sound no favours whatsoever, but is there any reason the 'digital volume' (much like a computer soundcard, I guess) is likely to be helping in a significant way? (If it is, I wonder why more manufacturers don't use them?) |
Digital volume control question....
On Fri, 19 May 2006 12:28:48 +0100, "Keith G"
wrote: A week or two ago I bought a little cheapo ss amplifier from Argos for fun/summer/curiosity/all day long radio, MP3s &c. and wuz so taken with it I bought a couple more (similarly cheap) components from the same range to go with it: http://www.apah69.dsl.pipex.com/show/outbreak.JPG (OK, I admit it - I was driven by the 3-way, multi-purpose remote control!! :-) Anyway, the clarity I'm getting from this little bugger from any number of different sources is quite exceptional and I'm wondering if the 'digital volume control' has anything to do with it? I know the speakers (firewood horns - Pinkies) are 'on song' now and will be contributing mostly to the sound quality and I am convinced that normal (carbon wiper) volume pots do the sound no favours whatsoever, but is there any reason the 'digital volume' (much like a computer soundcard, I guess) is likely to be helping in a significant way? (If it is, I wonder why more manufacturers don't use them?) No - in fact there is more chance that a poorly implemented digital control will damage the sound. But the real reason why your amp has a digital volume control is the usual one - cost. Pots cost money, they need mechanical fixings to support them and people have to bolt them in and wire them up. That is all bad news for a high-volume manufacturer. People are still resistant to digital volume controls in much of the market, though. I have a couple of amps with motorized volume pots. The reason why it all sounds so clear is that it is a normal SS amp and it isn't broken. These days it really doesn't have a lot of choice in the matter - you need to exert special efforts to make a bad amp these days, particularly if, as I suspect, this one uses chips for the PA stage. d -- Pearce Consulting http://www.pearce.uk.com |
Digital volume control question....
"Don Pearce" wrote in message ... On Fri, 19 May 2006 12:28:48 +0100, "Keith G" wrote: I know the speakers (firewood horns - Pinkies) are 'on song' now and will be contributing mostly to the sound quality and I am convinced that normal (carbon wiper) volume pots do the sound no favours whatsoever, but is there any reason the 'digital volume' (much like a computer soundcard, I guess) is likely to be helping in a significant way? (If it is, I wonder why more manufacturers don't use them?) No - in fact there is more chance that a poorly implemented digital control will damage the sound. But the real reason why your amp has a digital volume control is the usual one - cost. Sure, the amp only cost 60 quid brand new (with warranty)!! Pots cost money, they need mechanical fixings to support them and people have to bolt them in and wire them up. Yep. That is all bad news for a high-volume manufacturer. People are still resistant to digital volume controls in much of the market, though. Hmm.... I have a couple of amps with motorized volume pots. Nothing 'motorized' here - the *Control* knob (multifunctional) doesn't turn when the zapper's up and down buttons are being used and it rotates endlessly when being turned by hand.... (Bit like the manual focussing on my digital camera - OK on the amp, but pretty irritating on the camera!!) The reason why it all sounds so clear is that it is a normal SS amp and it isn't broken. These days it really doesn't have a lot of choice in the matter - you need to exert special efforts to make a bad amp these days, Yes, my suspicion also and why I bought the amp in the first place, to check it out. (See below...) particularly if, as I suspect, this one uses chips for the PA stage. PA stage?? (Preamplification?) I believe it's pretty hard to buy a bad *anything* much these days. I can understand stuff costing a lot of money if it uses a lot of expensive material or is hand-built (in a one-off kinda way) but I generally think the VFM factor is pretty high for what these things cost! As to the the volume control, I would consider that anything that took a carbon pot out of the occasion would be a good thing? (I don't know about 'poorly implemented' - why should it be poor? Is this one area where it would be particularly difficult to do the thing well?) My exploration into all this has been a staggering success AFAIAC - I have proved (to myself, if no other) that the *speakers* drive the whole 'hifi' thing *bigtime*! I would/will put this sound I'm getting off a cheap POS amp against anything I've heard to date!! In fact, I'll go as far as to say I don't much care about sources and amplification, the speakers can (and do) make or break it all!! I shudder to think how much money people are throwing at the game, trying to get a pair of iffy speakers to sound good. I swapped the Pinkies for a pair of very respectable JM-Labs the other day and the sound (from the exact same kit) slumped like punctured tyre!! I've got turntables/tuners/CDPs here that cost nowt and they all sound superb on the firewood horns, irrrespective of the amplifiers used!! Its revised my views completely, my advice to anyone looking for good sound on the cheap would/will be 'build a pair of speakers and then chuck any old kit at them' - I reckon you could get a superb tuner/CDP system going for less than 200 quid!! If me little mic weren't bust I'd post a track or two!! (Off to check out the mic anyway..... :-) |
Digital volume control question....
Keith G wrote:
A week or two ago I bought a little cheapo ss amplifier from Argos for fun/summer/curiosity/all day long radio, MP3s &c. and wuz so taken with it I bought a couple more (similarly cheap) components from the same range to go with it: http://www.apah69.dsl.pipex.com/show/outbreak.JPG (OK, I admit it - I was driven by the 3-way, multi-purpose remote control!! :-) Anyway, the clarity I'm getting from this little bugger from any number of different sources is quite exceptional and I'm wondering if the 'digital volume control' has anything to do with it? I know the speakers (firewood horns - Pinkies) are 'on song' now and will be contributing mostly to the sound quality and I am convinced that normal (carbon wiper) volume pots do the sound no favours whatsoever, but is there any reason the 'digital volume' (much like a computer soundcard, I guess) is likely to be helping in a significant way? (If it is, I wonder why more manufacturers don't use them?) As far as I know there are two sorts of "digital" volume control. One is a digitally controlled analogue attenuator, that changes its attenuation according to the numeric code it is given. This can be linked to a physical rotating control, driven from up-down counters etc. The second sort is a DSP function that multiplies the digital audio signal by varying co-efficients and outputs a digital signal who's values are an attenuated (or can be amplified) version of the input. I would imagine that the volume control of your amplifier is the former as it takes in and gives out analogue. The latter would require A-D and D-A conversions. Your Marantz CD player with the variable output could be of either sort but I suspect more the latter, as changing the digits before the D-A conversion would mean that the variable output would work on both the digital and analogue outputs simultaneously. As Don Pearce mentioned, the provision of a "digital" volume control is often done for reasons of cost. Digital volume controls track left and right channels virtually perfectly (comfortably within 0.1dB) from full output to extremely quiet, and don't generate any significant noise when changing levels. Normal carbon pots can be relatively quite noisy, and even conductive plastic pots will find it difficult to track both channels to better than 2dB at high attenuations. Carbon pots can be as much as 6dB out at low levels. This will move the stereo image around as you change volume settings. An electronic attenuator chip is a lot cheaper than a conductive plastic pot, and the actual mechanical control can be a cheap device, as all one is sensing is position. As to audio quality, a conductive plastic pot will have zero effect on audio quality. It is virtually pure resistance, and that doesn't have non-linearities or generate noise (other than Johnson noise, which is not terribly relevant.) A digital attenuator will have a finite level before overloading, and will generate some noise and distortion. However, that can be so low that it is essentially swamped by the inherent noise and distortion of the rest of the amplifier circuit. The only disadvantage of a "digital" volume control I can think of is that volume changes can only be made in discrete steps, typically 1dB at low volumes, perhaps 2 or even 3dB at high volumes. S. |
Digital volume control question....
On Fri, 19 May 2006 13:33:54 +0100, "Keith G"
wrote: "Don Pearce" wrote in message ... On Fri, 19 May 2006 12:28:48 +0100, "Keith G" wrote: I know the speakers (firewood horns - Pinkies) are 'on song' now and will be contributing mostly to the sound quality and I am convinced that normal (carbon wiper) volume pots do the sound no favours whatsoever, but is there any reason the 'digital volume' (much like a computer soundcard, I guess) is likely to be helping in a significant way? (If it is, I wonder why more manufacturers don't use them?) No - in fact there is more chance that a poorly implemented digital control will damage the sound. But the real reason why your amp has a digital volume control is the usual one - cost. Sure, the amp only cost 60 quid brand new (with warranty)!! Pots cost money, they need mechanical fixings to support them and people have to bolt them in and wire them up. Yep. That is all bad news for a high-volume manufacturer. People are still resistant to digital volume controls in much of the market, though. Hmm.... I have a couple of amps with motorized volume pots. Nothing 'motorized' here - the *Control* knob (multifunctional) doesn't turn when the zapper's up and down buttons are being used and it rotates endlessly when being turned by hand.... (Bit like the manual focussing on my digital camera - OK on the amp, but pretty irritating on the camera!!) The reason why it all sounds so clear is that it is a normal SS amp and it isn't broken. These days it really doesn't have a lot of choice in the matter - you need to exert special efforts to make a bad amp these days, Yes, my suspicion also and why I bought the amp in the first place, to check it out. (See below...) particularly if, as I suspect, this one uses chips for the PA stage. PA stage?? (Preamplification?) I believe it's pretty hard to buy a bad *anything* much these days. I can understand stuff costing a lot of money if it uses a lot of expensive material or is hand-built (in a one-off kinda way) but I generally think the VFM factor is pretty high for what these things cost! As to the the volume control, I would consider that anything that took a carbon pot out of the occasion would be a good thing? (I don't know about 'poorly implemented' - why should it be poor? Is this one area where it would be particularly difficult to do the thing well?) My exploration into all this has been a staggering success AFAIAC - I have proved (to myself, if no other) that the *speakers* drive the whole 'hifi' thing *bigtime*! I would/will put this sound I'm getting off a cheap POS amp against anything I've heard to date!! In fact, I'll go as far as to say I don't much care about sources and amplification, the speakers can (and do) make or break it all!! I shudder to think how much money people are throwing at the game, trying to get a pair of iffy speakers to sound good. I swapped the Pinkies for a pair of very respectable JM-Labs the other day and the sound (from the exact same kit) slumped like punctured tyre!! I've got turntables/tuners/CDPs here that cost nowt and they all sound superb on the firewood horns, irrrespective of the amplifiers used!! Its revised my views completely, my advice to anyone looking for good sound on the cheap would/will be 'build a pair of speakers and then chuck any old kit at them' - I reckon you could get a superb tuner/CDP system going for less than 200 quid!! If me little mic weren't bust I'd post a track or two!! (Off to check out the mic anyway..... :-) OK - we can stop calling you Grasshopper now; you've graduated. Oh, and PA is power amplifier. d -- Pearce Consulting http://www.pearce.uk.com |
Digital volume control question....
"Serge Auckland" wrote (If it is, I wonder why more manufacturers don't use them?) As far as I know there are two sorts of "digital" volume control. One is a digitally controlled analogue attenuator, that changes its attenuation according to the numeric code it is given. This can be linked to a physical rotating control, driven from up-down counters etc. The second sort is a DSP function that multiplies the digital audio signal by varying co-efficients and outputs a digital signal who's values are an attenuated (or can be amplified) version of the input. I would imagine that the volume control of your amplifier is the former as it takes in and gives out analogue. The latter would require A-D and D-A conversions. OK. Makes sense. Your Marantz CD player with the variable output could be of either sort but I suspect more the latter, as changing the digits before the D-A conversion would mean that the variable output would work on both the digital and analogue outputs simultaneously. And again. As Don Pearce mentioned, the provision of a "digital" volume control is often done for reasons of cost. Digital volume controls track left and right channels virtually perfectly (comfortably within 0.1dB) from full output to extremely quiet, and don't generate any significant noise when changing levels. Normal carbon pots can be relatively quite noisy, and even conductive plastic pots will find it difficult to track both channels to better than 2dB at high attenuations. Interesting. Carbon pots can be as much as 6dB out at low levels. Even more interesting (but not surprising)..... This will move the stereo image around as you change volume settings. An electronic attenuator chip is a lot cheaper than a conductive plastic pot, and the actual mechanical control can be a cheap device, as all one is sensing is position. As to audio quality, a conductive plastic pot will have zero effect on audio quality. It is virtually pure resistance, and that doesn't have non-linearities or generate noise (other than Johnson noise, which is not terribly relevant.) Oh I don't know - I would have thought a noisy Johnson could be a bit embarrassing at times!! ;-) A digital attenuator will have a finite level before overloading, and will generate some noise and distortion. However, that can be so low that it is essentially swamped by the inherent noise and distortion of the rest of the amplifier circuit. The only disadvantage of a "digital" volume control I can think of is that volume changes can only be made in discrete steps, typically 1dB at low volumes, perhaps 2 or even 3dB at high volumes. -1.25 dB steps across the range on this amp it appears.... Excellent answer Serge - thanks. Makes me think there's even less of a good reason for manufacturers to avoid them if, as Don says, they are 'properly implemented...??? I would have thought a standalone 'digital attenuator' (with remote?) would be a good thing for some valve amp owners - I wonder if such a thing is available?? |
Digital volume control question....
"Don Pearce" wrote in message ... On Fri, 19 May 2006 13:33:54 +0100, "Keith G" wrote: Its revised my views completely, my advice to anyone looking for good sound on the cheap would/will be 'build a pair of speakers and then chuck any old kit at them' - I reckon you could get a superb tuner/CDP system going for less than 200 quid!! OK - we can stop calling you Grasshopper now; you've graduated. (Ooh! Does this mean you've got ping-pong balls for eyes? :-) Anyway, I'm not sure I have 'graduated' (I suspect you are referring to the perennial valve vs, ss argument) - I've recommended cheap (eBay/secondhand) amps to people for ages. I've long suspected there wasn't much to choose between ss amps in a given price range and still think they all sound pretty boring/dull/grey/dreary/barren/bleak on 'normal' speakers whereas, by contrast, valve amps can be tweaked across a fairly broad range to *tailor* a particular (more pleasing) sound. But that's not the issue, what is a revelation to me is just how much the speakers are dictating the final result from a 'hifi' system - I now believe a ****e pair of speakers (includes Famous Names) can fatally cripple just about *any* source or amplifier!! I'm not thumping any particular tub here - I just think it's a pity that people are unloading a *lot* of money to get something satisfying from a pair of speakers that ain't *ever* going to deliver the goods when the solution (OK, not for everybody, possibly) is so damn cheap! If I wuz 10 (OK - 20 or 30....) years younger I would be seriously thinking of producing a VFM horn speaker on a commercial basis!! Two things, I think, have steered the modern trends - the inexplicable* need for unnecessary, loud, pistonic bass in (paradoxically) a small 'user/wife friendly' enclosure! Consequently amplifiers have to be capable of outputting three figures of totally unnecessary and expensive watts (in the average UK room) to get 'em to work at all and that brings a raft of other considerations into the equation which are simply not of much consequence when driving sensitive speakers with low-power amps. (Distortion, power supply issues etc.) Interesting that there's nothing particularly small about 'high end' speakers, innit? *Actually, not that inexplicable, given the nature of much modern *tribal* music....!! |
Digital volume control question....
Keith G wrote:
"Serge Auckland" wrote (If it is, I wonder why more manufacturers don't use them?) As far as I know there are two sorts of "digital" volume control. One is a digitally controlled analogue attenuator, that changes its attenuation according to the numeric code it is given. This can be linked to a physical rotating control, driven from up-down counters etc. The second sort is a DSP function that multiplies the digital audio signal by varying co-efficients and outputs a digital signal who's values are an attenuated (or can be amplified) version of the input. I would imagine that the volume control of your amplifier is the former as it takes in and gives out analogue. The latter would require A-D and D-A conversions. OK. Makes sense. Your Marantz CD player with the variable output could be of either sort but I suspect more the latter, as changing the digits before the D-A conversion would mean that the variable output would work on both the digital and analogue outputs simultaneously. And again. As Don Pearce mentioned, the provision of a "digital" volume control is often done for reasons of cost. Digital volume controls track left and right channels virtually perfectly (comfortably within 0.1dB) from full output to extremely quiet, and don't generate any significant noise when changing levels. Normal carbon pots can be relatively quite noisy, and even conductive plastic pots will find it difficult to track both channels to better than 2dB at high attenuations. Interesting. Carbon pots can be as much as 6dB out at low levels. Even more interesting (but not surprising)..... This will move the stereo image around as you change volume settings. An electronic attenuator chip is a lot cheaper than a conductive plastic pot, and the actual mechanical control can be a cheap device, as all one is sensing is position. As to audio quality, a conductive plastic pot will have zero effect on audio quality. It is virtually pure resistance, and that doesn't have non-linearities or generate noise (other than Johnson noise, which is not terribly relevant.) Oh I don't know - I would have thought a noisy Johnson could be a bit embarrassing at times!! ;-) A digital attenuator will have a finite level before overloading, and will generate some noise and distortion. However, that can be so low that it is essentially swamped by the inherent noise and distortion of the rest of the amplifier circuit. The only disadvantage of a "digital" volume control I can think of is that volume changes can only be made in discrete steps, typically 1dB at low volumes, perhaps 2 or even 3dB at high volumes. -1.25 dB steps across the range on this amp it appears.... Excellent answer Serge - thanks. Makes me think there's even less of a good reason for manufacturers to avoid them if, as Don says, they are 'properly implemented...??? I would have thought a standalone 'digital attenuator' (with remote?) would be a good thing for some valve amp owners - I wonder if such a thing is available?? I would have thought that as soon as the word "digital" is mentioned many valve amp owners will run a mile..... There are a number of passive volume controllers available albeit at ludicrous prices for what is basically a good quality pot in a tin box; and not forgetting the multi-tapped transformer controller which will have all the benefits and cons of a digital controller, but again at vastly increased cost and price. S. |
Digital volume control question....
On Fri, 19 May 2006 16:01:35 +0100, "Keith G"
wrote: "Don Pearce" wrote in message ... On Fri, 19 May 2006 13:33:54 +0100, "Keith G" wrote: Its revised my views completely, my advice to anyone looking for good sound on the cheap would/will be 'build a pair of speakers and then chuck any old kit at them' - I reckon you could get a superb tuner/CDP system going for less than 200 quid!! OK - we can stop calling you Grasshopper now; you've graduated. (Ooh! Does this mean you've got ping-pong balls for eyes? :-) I did have last weekend when I was headbutted in the nuts by a two-year-old. Anyway, I'm not sure I have 'graduated' (I suspect you are referring to the perennial valve vs, ss argument) - I've recommended cheap (eBay/secondhand) amps to people for ages. I've long suspected there wasn't much to choose between ss amps in a given price range and still think they all sound pretty boring/dull/grey/dreary/barren/bleak on 'normal' speakers whereas, by contrast, valve amps can be tweaked across a fairly broad range to *tailor* a particular (more pleasing) sound. But that's not the issue, what is a revelation to me is just how much the speakers are dictating the final result from a 'hifi' system - I now believe a ****e pair of speakers (includes Famous Names) can fatally cripple just about *any* source or amplifier!! No, not referring to valves vs SS - that is just preference. More the fact that there is nothing more to be had from SS by spending more money. The plateau starts *really* low. I'm not thumping any particular tub here - I just think it's a pity that people are unloading a *lot* of money to get something satisfying from a pair of speakers that ain't *ever* going to deliver the goods when the solution (OK, not for everybody, possibly) is so damn cheap! If I wuz 10 (OK - 20 or 30....) years younger I would be seriously thinking of producing a VFM horn speaker on a commercial basis!! Two things, I think, have steered the modern trends - the inexplicable* need for unnecessary, loud, pistonic bass in (paradoxically) a small 'user/wife friendly' enclosure! Consequently amplifiers have to be capable of outputting three figures of totally unnecessary and expensive watts (in the average UK room) to get 'em to work at all and that brings a raft of other considerations into the equation which are simply not of much consequence when driving sensitive speakers with low-power amps. (Distortion, power supply issues etc.) Expensive watts? No, those watts are really, really cheap, especially for subwoofers that use switching supplies and power amps. Interesting that there's nothing particularly small about 'high end' speakers, innit? Some friends of mine have Willson Maxx speakers. They weigh about half a ton and sound equally good when bending the walls or barely murmuring. They also stand about five feet high. *Actually, not that inexplicable, given the nature of much modern *tribal* music....!! Truth. d -- Pearce Consulting http://www.pearce.uk.com |
Digital volume control question....
Keith G wrote:
My exploration into all this has been a staggering success AFAIAC - I have proved (to myself, if no other) that the *speakers* drive the whole 'hifi' thing *bigtime*! I would/will put this sound I'm getting off a cheap POS amp against anything I've heard to date!! In fact, I'll go as far as to say I don't much care about sources and amplification, the speakers can (and do) make or break it all!! I shudder to think how much money people are throwing at the game, trying to get a pair of iffy speakers to sound good. I swapped the Pinkies for a pair of very respectable JM-Labs the other day and the sound (from the exact same kit) slumped like punctured tyre!! I've got turntables/tuners/CDPs here that cost nowt and they all sound superb on the firewood horns, irrrespective of the amplifiers used!! Its revised my views completely, my advice to anyone looking for good sound on the cheap would/will be 'build a pair of speakers and then chuck any old kit at them' - I reckon you could get a superb tuner/CDP system going for less than 200 quid!! If me little mic weren't bust I'd post a track or two!! (Off to check out the mic anyway..... :-) This reminds of the ludicrous situation that was common in the mid eighties when Linn in particular suggested a Linn-Ittok-Asak combination for use with a little Nytech or NAIM amp and Linn Kan 'speakers. The results were truly horrible entirely due to the appalling 'speakers. I really felt for people who had wasted their money in that way but what could a layman do when every mag recommended such folly. When I was in retail at the time I tried to fight against it, putting 'speakers first, then decent amplification and a CD player, but went bust for my pains. Ah well..... S. |
Digital volume control question....
"Don Pearce" wrote in message ... On Fri, 19 May 2006 16:01:35 +0100, "Keith G" wrote: (Ooh! Does this mean you've got ping-pong balls for eyes? :-) I did have last weekend when I was headbutted in the nuts by a two-year-old. Nasty... (When that happens it's faster than a lightning strike, innit? :-) No, not referring to valves vs SS - that is just preference. Agreed. More the fact that there is nothing more to be had from SS by spending more money. The plateau starts *really* low. Yes, well under a hundred quid from I can see of it!! Two things, I think, have steered the modern trends - the inexplicable* need for unnecessary, loud, pistonic bass in (paradoxically) a small 'user/wife friendly' enclosure! Consequently amplifiers have to be capable of outputting three figures of totally unnecessary and expensive watts (in the average UK room) to get 'em to work at all and that brings a raft of other considerations into the equation which are simply not of much consequence when driving sensitive speakers with low-power amps. (Distortion, power supply issues etc.) Expensive watts? No, those watts are really, really cheap, especially for subwoofers that use switching supplies and power amps. Well, I reckon a 30 wpc amp will work out at about 2 to 4 quid per watt, but the trouble is you *need* 100+ watts these days (ludicrous) and then I reckon you are looking at 5 times that sort of money *at least* for similar (construction/appearance/appointments) 'assembly line' amps....?? Interesting that there's nothing particularly small about 'high end' speakers, innit? Some friends of mine have Willson Maxx speakers. They weigh about half a ton and sound equally good when bending the walls or barely murmuring. They also stand about five feet high. My point entirely..... :-) |
Digital volume control question....
"Serge Auckland" wrote Its revised my views completely, my advice to anyone looking for good sound on the cheap would/will be 'build a pair of speakers and then chuck any old kit at them' - I reckon you could get a superb tuner/CDP system going for less than 200 quid!! This reminds of the ludicrous situation that was common in the mid eighties when Linn in particular suggested a Linn-Ittok-Asak combination for use with a little Nytech or NAIM amp and Linn Kan 'speakers. The results were truly horrible entirely due to the appalling 'speakers. I really felt for people who had wasted their money in that way but what could a layman do when every mag recommended such folly. Missed that era - too busy working (and misbehaving) to worry about *hifi*!! (Which is how I managed to avoid getting swept up in the 'CD - perfect sound forever' mass hysteria!!) When I was in retail at the time I tried to fight against it, putting 'speakers first, then decent amplification and a CD player, but went bust for my pains. Ah well..... For some strange reason most dealers and punters put the emphasis on the amplifier and call it the *heart* of the system - this day and age, it's the *last* thing to worry about, as has been noted in this thread (and others) recently!! ........Unless it's got blue LEDs, of course....!! ;-) |
Digital volume control question....
"Serge Auckland" wrote I would have thought that as soon as the word "digital" is mentioned many valve amp owners will run a mile..... Nah - don't take too much notice of my responses to Arny's valve/vinyl attacks!! ;-) Although I can't ever see myself sitting down to a CD of an evening (wot a peculiar notion???), I often have them on during the day - not to mention DAB radio and MP3s when the occasion deems suitable!! In a few minutes I'm orf down the road and will be playing a CDRW rip of an LP (wot else?) on my newly-fitted 'Chav Blue' car CD player!! (The first one I've ever had - looks like crap and sounds brilliant!! :-) See it in the box he http://www.apah69.dsl.pipex.com/show/thompsontwins.JPG Heejus, innit? :-) There are a number of passive volume controllers available albeit at ludicrous prices for what is basically a good quality pot in a tin box; Been there, done that: http://www.apah69.dsl.pipex.com/passives/passives.htm (Ended up ripping the pot out to replace the duff one in one of my Chinese 300B SETs and haven't got round to replacing yet!!) and not forgetting the multi-tapped transformer controller which will have all the benefits and cons of a digital controller, but again at vastly increased cost and price. Not going there, not going to do that..... |
Digital volume control question....
"Keith G" wrote Well, I reckon a 30 wpc amp will work out at about 2 to 4 quid per watt, but the trouble is you *need* 100+ watts these days (ludicrous) and then I reckon you are looking at 5 times that sort of money *at least* for similar (construction/appearance/appointments) 'assembly line' amps....?? No, that stinks - what I meant was a 30 watt amp will cost somewhere around a hundred nicker (or even less, it seems), a 100+ watt amp will likely cost 500 quid or more. (ie 5 times the price!!) |
Digital volume control question....
Serge Auckland wrote
I would have thought that as soon as the word "digital" is mentioned many valve amp owners will run a mile..... There are a number of passive volume controllers available albeit at ludicrous prices for what is basically a good quality pot in a tin box; and not forgetting the multi-tapped transformer controller which will have all the benefits and cons of a digital controller, but again at vastly increased cost and price. The DSP solution would appear to be preferable. However, presumably there are rounding errors. That is, if I divide every word by a constant, each result must be rounded to the nearest step, and this rounding error is not linear wrt the audio signal. I assume there is a name for this kind of error? How significant is it? A digitally controlled attenuator chip contains not only a resistor ladder, but also a heap of semiconductors to do the switching. I expect those who object to them are wary of the SS junctions in, and perhaps also parallel to, the signal path. A motorised pot may be an expensive component, but it is easier to program the control system. The pot remembers where it is, and only needs 2 bits to control. OTOH, it is not convenient to use if you want a rotary control on your remote. I have never seen a remote with a rotary volume control. Why not? If the link is reasonably error free, then it should be possible to put a rotary encoder on the remote as well as on the system case. I hate push-button volume controls. As for what valve aficionados might think, look he http://stiftsbogtrykkeriet.dk/~mcs/index.html cheers, Ian S. |
Digital volume control question....
Ian Iveson wrote:
The DSP solution would appear to be preferable. However, presumably there are rounding errors. That is, if I divide every word by a constant, each result must be rounded to the nearest step, and this rounding error is not linear wrt the audio signal. I assume there is a name for this kind of error? How significant is it? The DSP solutions I'm familiar with operate either floating point or 32 or 48 bit internal which means that when the output is finally reduced to 16 or 24 bit the errors from the DSP calculations are minimised. I don't know of a specific name for the errors resulting from DSP operation. A digitally controlled attenuator chip contains not only a resistor ladder, but also a heap of semiconductors to do the switching. I expect those who object to them are wary of the SS junctions in, and perhaps also parallel to, the signal path. A motorised pot may be an expensive component, but it is easier to program the control system. The pot remembers where it is, and only needs 2 bits to control. OTOH, it is not convenient to use if you want a rotary control on your remote. The main problems with all pots, motorised or otherwise is tracking over a stereo pair. With 5.1 surround, there would have to be 6 tracking controls so some form of electronic volume is almost essential. I have never seen a remote with a rotary volume control. Why not? If the link is reasonably error free, then it should be possible to put a rotary encoder on the remote as well as on the system case. I hate push-button volume controls. I don't think I've ever seen one either. The closest was a rotary shuttle control for a S-VHS VTR which would allow frame by frame forward or backwards movement. Now that I think about it a bit more, didn't QUAD have one on their 66 and 77 series? S. |
Digital volume control question....
On 2006-05-19, Serge Auckland wrote:
Ian Iveson wrote: The DSP solution would appear to be preferable. However, presumably there are rounding errors. That is, if I divide every word by a constant, each result must be rounded to the nearest step, and this rounding error is not linear wrt the audio signal. I assume there is a name for this kind of error? How significant is it? The DSP solutions I'm familiar with operate either floating point or 32 or 48 bit internal which means that when the output is finally reduced to 16 or 24 bit the errors from the DSP calculations are minimised. I don't know of a specific name for the errors resulting from DSP operation. I guess a digital volume control can just be a single fixed-point multiply. If you have (for example) a 16-bit coefficient and multiply by the 16-bit audio value you get a 32-bit result. Growth in significant bits is typical of DSP actions such as add and multiply. If you just truncate the result back to 16 bits you do indeed find that the quantization error you introduce is correlated with the signal. It is significant and sounds bad at low levels. In a good DSP (volume control) the remedy is to keep all significant bits throughout the entire operation (or at least keep enough) and add dither noise before you finally truncate back to the desired word size. The random dither de-correlates the quantization error from the signal. I assume that's what good DSP volume controls do. -- John Phillips |
Digital volume control question....
On Fri, 19 May 2006 19:02:31 +0100, "Keith G"
wrote: Well, I reckon a 30 wpc amp will work out at about 2 to 4 quid per watt, but the trouble is you *need* 100+ watts these days (ludicrous) and then I reckon you are looking at 5 times that sort of money *at least* for similar (construction/appearance/appointments) 'assembly line' amps....?? Untrue for subs, Keith. You can buy a 500 watt 'plate' amp with active crossover and all necessary connections and controls, for less then three hundred quid. Just the job for getting deep, clean bass down to 20Hz at decent SPLs from an 18" cube. Also one of the last remaining areas where the home builder can beat the commercial stuff. -- Stewart Pinkerton | Music is Art - Audio is Engineering Posted Via Usenet.com Premium Usenet Newsgroup Services ---------------------------------------------------------- ** SPEED ** RETENTION ** COMPLETION ** ANONYMITY ** ---------------------------------------------------------- http://www.usenet.com |
Digital volume control question....
Serge Auckland wrote:
Ian Iveson wrote: The DSP solution would appear to be preferable. However, presumably there are rounding errors. That is, if I divide every word by a constant, each result must be rounded to the nearest step, and this rounding error is not linear wrt the audio signal. I assume there is a name for this kind of error? How significant is it? The DSP solutions I'm familiar with operate either floating point or 32 or 48 bit internal which means that when the output is finally reduced to 16 or 24 bit the errors from the DSP calculations are minimised. I don't know of a specific name for the errors resulting from DSP operation. But even if the internal calculation is done with larger resolution, you still loose one bit of output resolution for every 6db of attenuation. -- Nick |
Digital volume control question....
In article , John Phillips
wrote: On 2006-05-19, Serge Auckland wrote: Ian Iveson wrote: The DSP solution would appear to be preferable. However, presumably there are rounding errors. That is, if I divide every word by a constant, each result must be rounded to the nearest step, and this rounding error is not linear wrt the audio signal. I assume there is a name for this kind of error? How significant is it? The DSP solutions I'm familiar with operate either floating point or 32 or 48 bit internal which means that when the output is finally reduced to 16 or 24 bit the errors from the DSP calculations are minimised. I don't know of a specific name for the errors resulting from DSP operation. I have tended to see it called by various terms from "quantisation error" and "truncation error" to "we''ll ignore this..." :-) I guess a digital volume control can just be a single fixed-point multiply. If you have (for example) a 16-bit coefficient and multiply by the 16-bit audio value you get a 32-bit result. Yes. In principle you can do that. Indeed, I think that many consumer chips simply use such 'extended' int values for processing in places like the digital filtering. Growth in significant bits is typical of DSP actions such as add and multiply. If you just truncate the result back to 16 bits you do indeed find that the quantization error you introduce is correlated with the signal. It is significant and sounds bad at low levels. In a good DSP (volume control) the remedy is to keep all significant bits throughout the entire operation (or at least keep enough) and add dither noise before you finally truncate back to the desired word size. The random dither de-correlates the quantization error from the signal. I assume that's what good DSP volume controls do. Dither will certainly help avoid such problems. However you can also employ noise shaping. This essentially 'remembers' the quantisation errors and redistibutes the information. The result is to provide output signal pattern details which can be below the LSB, so helping to evade the problem. Again, I think that many consumer chips do this were appropriate as it is easy to build into the silicon. The snag is that the above is all a matter of the details of implimentation. Whereas a decent analog attenuator simply uses the properties of the physical materials to do all this for you. No need for the makers to work out a noise-shaping anf dithering process and ensure sufficient precision, etc. :-) Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
Digital volume control question....
In article ,
Keith G wrote: Anyway, the clarity I'm getting from this little bugger from any number of different sources is quite exceptional and I'm wondering if the 'digital volume control' has anything to do with it? No - a digital volume control might well make things worse. Welcome to the 21st century where cheap SS amps beat the s**t out of most valve amps at anything near an affordable price... -- *(over a sketch of the titanic) "The boat sank - get over it Dave Plowman London SW To e-mail, change noise into sound. |
Digital volume control question....
Serge Auckland wrote
The DSP solution would appear to be preferable. However, presumably there are rounding errors. That is, if I divide every word by a constant, each result must be rounded to the nearest step, and this rounding error is not linear wrt the audio signal. I assume there is a name for this kind of error? How significant is it? The DSP solutions I'm familiar with operate either floating point or 32 or 48 bit internal which means that when the output is finally reduced to 16 or 24 bit the errors from the DSP calculations are minimised. The error would be reduced by the same ratio as the conversion I suppose. I don't know of a specific name for the errors resulting from DSP operation. Perhaps it is no different from the usual sampling error, and possibly makes sod all difference to the total. A digitally controlled attenuator chip contains not only a resistor ladder, but also a heap of semiconductors to do the switching. I expect those who object to them are wary of the SS junctions in, and perhaps also parallel to, the signal path. A motorised pot may be an expensive component, but it is easier to program the control system. The pot remembers where it is, and only needs 2 bits to control. OTOH, it is not convenient to use if you want a rotary control on your remote. The main problems with all pots, motorised or otherwise is tracking over a stereo pair. Yes, good point. I guess better matching is part of why better quality stereo pots are better, but the problem is always there to some extent. I get the impression these days that the best digital attenuator chips are at least as good as anything else. With 5.1 surround, there would have to be 6 tracking controls so some form of electronic volume is almost essential. I guess so...and much more than 6 times harder to match. Not into multichannel; it's bad enough having to make everything twice. I have never seen a remote with a rotary volume control. Why not? If the link is reasonably error free, then it should be possible to put a rotary encoder on the remote as well as on the system case. I hate push-button volume controls. I don't think I've ever seen one either. The closest was a rotary shuttle control for a S-VHS VTR which would allow frame by frame forward or backwards movement. Now that I think about it a bit more, didn't QUAD have one on their 66 and 77 series? Looks like it in this pic http://www.whats-new-at-totallywired.com/specials.html Come to think of it, not easy to do with the usual remote coding systems. The most reliable way would be to send the absolute position, rather than a string of increments. That would require a different code for each position of the attenuator. I guess Quad used their own coding scheme. DIY remotes tend to use RC5 or Sony codes, so you don't need to make your own transmitter. I have a remote output level control on this quirky Sony CD player that I can compare quite easily with my Alps pot. I have never tried it because it defaults to bypass on power-up. I'll give it a try and report back if I can hear any difference. Don't wait up... Oddly, and infuriatingly, this same machine uses a front panel pot for the headphone output, with no control on the remote, AFAIK. I wonder how they make these decisions. cheers, Ian |
Digital volume control question....
"Jim Lesurf" wrote in message ... In article , Keith G wrote: As Don Pearce mentioned, the provision of a "digital" volume control is often done for reasons of cost. Digital volume controls track left and right channels virtually perfectly (comfortably within 0.1dB) from full output to extremely quiet, and don't generate any significant noise when changing levels. Normal carbon pots can be relatively quite noisy, and even conductive plastic pots will find it difficult to track both channels to better than 2dB at high attenuations. Interesting. FWIW some of the larger and more expensive 'pots' are stepped attenuators with laser-trimmed resistances. One of the benefits of these can be much closer tracking of the balance as you wind down the level. They may also use 'landings' between the settings that are particularly good at not deteriorating with age/use. However they have tended to cost far more than simple pots... Excellent answer Serge - thanks. Makes me think there's even less of a good reason for manufacturers to avoid them if, as Don says, they are 'properly implemented...??? The problem is that the 'proper implimentation' involves processes which the user can't directly check, and the makers may be lazy or trying to cut corners... I would have thought a standalone 'digital attenuator' (with remote?) would be a good thing for some valve amp owners - I wonder if such a thing is available?? The concerns may be: 1: such a unit would require its own power and ADC/DAC, buffers, etc. 2: Would valve/analog enthusiasts wish to have this digital/solidstate device always in their signal chain? I'd have thought they'd fear it would corrupt the 'purity' of their system. :-) 3: Good quality stepped attenuators and detented pots exist and can work fine. FWIW I have always used the ALP 40mm stepped detent volume controls. When I bought them commercially in the past I got them with tight levels of balance, etc, spec. If you can find a source for these, I'd recommend you try them. You may find they give an active attenuator a run for its money. That's all very interesting but a little way wide of the point - forget expensive, 'laser cut' options, my curiosity here is that in an amp costing only 60 quid (and which includes 6 inputs, headphone socket, phono stage as well as all the necessary ADC/DAC circuitry, power supply &c.) there is a very useful *digital* (ie cheap) way of controlling volume/treble/bass/balance/muting/'loudness' with some of the major functions (not all) available on the (included) remote control. I reckon this could be of interest to some (if not many) valve amp users, as none of these functions are normally available outside of arm's length with valve amps and some are not usually available at all! I know there are times when I wouldn't mind being able to make various adjustments without having to get up - volume being the obvious choice, but being able to zap to a tuner after a record has finished (and the deck switched itself off) and then change stations (when the volume control would be *essential*) would be neat!! If 'properly implemented' means that any artifacts, digital 'rounding off' or whatever are *inaudible* there might be the possibility of an inexpensive digital 'front end' which offers the convenience of remote control on the main functions as well the additional capability to adjust tone/balance/loudness/muting &c. (An amusing concept on a valve amp!!) Or, as the price of the whole amp is peanuts, I would even go as far as to suggest that someone with more expertise than me could butcher one of these amps to create a very interesting 'digital pre' with all the afore-mentioned functionality! ;-) |
Digital volume control question....
"Stewart Pinkerton" wrote in message ... On Fri, 19 May 2006 19:02:31 +0100, "Keith G" wrote: Well, I reckon a 30 wpc amp will work out at about 2 to 4 quid per watt, but the trouble is you *need* 100+ watts these days (ludicrous) and then I reckon you are looking at 5 times that sort of money *at least* for similar (construction/appearance/appointments) 'assembly line' amps....?? Untrue for subs, Keith. You can buy a 500 watt 'plate' amp with active crossover and all necessary connections and controls, for less then three hundred quid. Just the job for getting deep, clean bass down to 20Hz at decent SPLs from an 18" cube. Also one of the last remaining areas where the home builder can beat the commercial stuff. The thing with home builders is that just about all of them think they are beating the commercial stuff or I guess they wouldn't bother?? But it's not all about the money - many DIYers are looking to beat commercial stuff in terms of ultimate performance/specification and are well aware they would definitely *not* be beating commercial producers on a cost basis if their own labour was priced into the equation....!!?? |
Digital volume control question....
"Dave Plowman (News)" wrote in message ... In article , Keith G wrote: Anyway, the clarity I'm getting from this little bugger from any number of different sources is quite exceptional and I'm wondering if the 'digital volume control' has anything to do with it? No - a digital volume control might well make things worse. Welcome to the 21st century where cheap SS amps beat the s**t out of most valve amps at anything near an affordable price... I'm afraid I don't share your view - much as I like the various/numerous ss gadgets I use (and enjoy) here, when it comes to amplifiers and playing *music* none of them beat the various valve amps I've got. (Quite simply, you either *get that* or you don't....) Try to get past this 'mutual exclusivity' thing - you don't have to make *final* choices forever, you can drink both Coca Cola and Pepsi Cola if you want to.... |
Digital volume control question....
Keith G wrote:
The thing with home builders is that just about all of them think they are beating the commercial stuff or I guess they wouldn't bother?? But it's not all about the money - many DIYers are looking to beat commercial stuff in terms of ultimate performance/specification and are well aware they would definitely *not* be beating commercial producers on a cost basis if their own labour was priced into the equation....!!?? Some people want to climb a mountain because it is there. The people that put a wall around that idea don't understand the enjoyment one gets in making the journey - no matter how ill looking the end looks (or not!) I take my hat off to this person and many like her. http://en.wikipedia.org/wiki/Jeri_Ellsworth DIY electronics rules forever! -- Adrian C |
Digital volume control question....
Adrian C wrote:
Keith G wrote: The thing with home builders is that just about all of them think they are beating the commercial stuff or I guess they wouldn't bother?? But it's not all about the money - many DIYers are looking to beat commercial stuff in terms of ultimate performance/specification and are well aware they would definitely *not* be beating commercial producers on a cost basis if their own labour was priced into the equation....!!?? Some people want to climb a mountain because it is there. The people that put a wall around that idea don't understand the enjoyment one gets in making the journey - no matter how ill looking the end looks (or not!) I take my hat off to this person and many like her. http://en.wikipedia.org/wiki/Jeri_Ellsworth DIY electronics rules forever! Absolutely! Like many of my generation I got into electronics through the DIY route, trailing round the component shops in Lisle St in London, falling over the ladies of the night in our search for some particular component! Sadly, now, just buying components is a trial in itself. It has to be mail-order or forget it. One notable exception is the wonderful emporium of Gee's in Cambridge. A real old-fashioned component shop staffed by a great guy who's been there since Schottky was a lad. Sadly building one's own stuff from scratch is a lot more expensive than buying it built. Stewart mentioned buying plate amplifiers for sub-woofers, which is fine, but if you want to make your own amplifiers you end up spending a lot more than buying one. Keith's own experience with the POS amplifiers shows this up well. There's no way you can even buy the box for the price of the complete unit from Comet, Argos or whoever. I hope there will always be a DIY sector interested in building stiff not because it's cheaper but because it's a lot more satisfying. More power to your soldering iron. S. |
Digital volume control question....
Hi,
"Serge Auckland" wrote in message ... This reminds of the ludicrous situation that was common in the mid eighties when Linn in particular suggested a Linn-Ittok-Asak combination for use with a little Nytech or NAIM amp and Linn Kan 'speakers. The results were truly horrible entirely due to the appalling 'speakers. I really felt for people who had wasted their money in that way but what could a layman do when every mag recommended such folly. Hi-Fi Answers perchance? I remember their long, drawn out arguments on why "garbage in meant garbage out", and being young and naive I almost fell for it. Fortunately the old boy at the local electrical shop (no 'proper' hi-fi shop nearby then or now) put me straight and made me sit down and listen to some systems. I came out with a good one, and I've been a major sceptic about all 'hobby' magazine recommendations ever since. When I was in retail at the time I tried to fight against it, putting 'speakers first, then decent amplification and a CD player, but went bust for my pains. Ah well..... Good man. At least you were on the right side. Sometimes it's better to be right than to win the argument. Sorry it meant you going bust though... Regards, Glenn. |
Digital volume control question....
In article , Keith G
wrote: "Jim Lesurf" wrote in message ... [big snip] That's all very interesting but a little way wide of the point - forget expensive, 'laser cut' options, my curiosity here is that in an amp costing only 60 quid (and which includes 6 inputs, headphone socket, phono stage as well as all the necessary ADC/DAC circuitry, power supply &c.) there is a very useful *digital* (ie cheap) way of controlling volume/treble/bass/balance/muting/'loudness' with some of the major functions (not all) available on the (included) remote control. Yes, I'd agree. I was just pointing out that some people have an aversion to anything 'digital', and that a 'digital attenuator' may have flaws, so should assessed with due care. But the silicon for one is cheap, and should be able to give good results if well done. Note also that applying tonal changes (treble, bass, etc) is slightly more complex, so again should be fine if well implimented, but... If 'properly implemented' means that any artifacts, digital 'rounding off' or whatever are *inaudible* there might be the possibility of an inexpensive digital 'front end' which offers the convenience of remote control on the main functions as well the additional capability to adjust tone/balance/loudness/muting &c. (An amusing concept on a valve amp!!) Yes. However the above comment should be applied with caution in practice since it starts by assuming that the imperfections *are* "inaudible". The snag is that they may not be. For example, a digital volume control will have a clipping level in a way that an analogue one does not. This may not matter for some applications, but be vital in others. Hence "inaudible" will depend both on the volume control and the specific use. I don't have any real objection in principle to 'digital' controls. Indeed, I tend to prefer processing signals in digital form when the process needs flexibility, etc. However the reality is that an ADC-process-DAC-psu-clock combination is electrically more complex than a pair of resistors. Hence it gives the poor designer/maker more options for making errors. :-) Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
Digital volume control question....
"Serge Auckland" wrote Sadly building one's own stuff from scratch is a lot more expensive than buying it built. Stewart mentioned buying plate amplifiers for sub-woofers, which is fine, but if you want to make your own amplifiers you end up spending a lot more than buying one. Keith's own experience with the POS amplifiers shows this up well. There's no way you can even buy the box for the price of the complete unit from Comet, Argos or whoever. I would just like to point out that my recent excursion into the cheap 'n' cheerful Argos kit is just another of my 'investigative/curiosity' trips and I wouldn't claim that this sort of kit (almost toys, if you go by price) would satisfy many people - the price/POQ alone will prevent many from taking it seriously or being content with it on a long-term basis, I would guess. Take it from me that the sound quality is well up snuff compared with what cheaper 'mid-fi' kit I've heard (including the Roksan Kandy mentioned elsewhere) and the build quality is not far (if at all) behind, although only time will tell in respect of durability....?? (At the end of the day *cheap* never really does anybody any favours - factor life, but if the cheap stuff is at least OK/usable, gets people *into* decent sound and possibly starts them off on an upgrade path (groan) it possibly isn't completely bad news for the industry....??) I hope there will always be a DIY sector interested in building stiff not because it's cheaper but because it's a lot more satisfying. Well, the diyaudio.com forum: http://www.diyaudio.com/index.php?s=...857351d6501ec0 claims 54,824 members and there are *countless* other such forums (fori? fora?) on the Net these days, so I guess it's not looking too bad! (Plus it seems that there's plenty of people ready to *tweak* just about any bit of electronics kit you can get these days - audio, AV, TV and computer!!) More power to your soldering iron. Ooh, er!! Steady on, old bean!! :-) |
Digital volume control question....
On 2006-05-20, Jim Lesurf wrote:
In article , John Phillips wrote: ... I assume that's what good DSP volume controls do. ... The snag is that the above is all a matter of the details of implimentation. Whereas a decent analog attenuator simply uses the properties of the physical materials to do all this for you. No need for the makers to work out a noise-shaping anf dithering process and ensure sufficient precision, etc. :-) True, but once you have worked it out once it's very easy to replicate and does not have the degradation mechanisms. -- John Phillips |
Digital volume control question....
"Jim Lesurf" wrote in message ... In article , Keith G wrote: "Jim Lesurf" wrote in message ... [big snip] That's all very interesting but a little way wide of the point - forget expensive, 'laser cut' options, my curiosity here is that in an amp costing only 60 quid (and which includes 6 inputs, headphone socket, phono stage as well as all the necessary ADC/DAC circuitry, power supply &c.) there is a very useful *digital* (ie cheap) way of controlling volume/treble/bass/balance/muting/'loudness' with some of the major functions (not all) available on the (included) remote control. Yes, I'd agree. I was just pointing out that some people have an aversion to anything 'digital', They *do*....??? (How strange!! ;-) and that a 'digital attenuator' may have flaws, so should assessed with due care. But the silicon for one is cheap, and should be able to give good results if well done. Yes, if not done at least reasonably well then best not done at all, like most things. I don't think these cheap amps would suit the more demanding or perhaps, more discerning user, but bearing in mind the price, the sound levels do go up and down much like you'd expect them to when you press the appropriate buttons (or turn the knob)!! Note also that applying tonal changes (treble, bass, etc) is slightly more complex, so again should be fine if well implimented, but... Yes, I can see that it might be a bit more complicated. Asitappens, I'm not a great Tone Control user myself (apart from hacking the treble off a bit on a *really* busy record) but I think it's always good to have the option. If 'properly implemented' means that any artifacts, digital 'rounding off' or whatever are *inaudible* there might be the possibility of an inexpensive digital 'front end' which offers the convenience of remote control on the main functions as well the additional capability to adjust tone/balance/loudness/muting &c. (An amusing concept on a valve amp!!) Yes. However the above comment should be applied with caution in practice since it starts by assuming that the imperfections *are* "inaudible". The snag is that they may not be. For example, a digital volume control will have a clipping level in a way that an analogue one does not. This may not matter for some applications, but be vital in others. Hence "inaudible" will depend both on the volume control and the specific use. Sure... I don't have any real objection in principle to 'digital' controls. Indeed, I tend to prefer processing signals in digital form when the process needs flexibility, etc. However the reality is that an ADC-process-DAC-psu-clock combination is electrically more complex than a pair of resistors. Hence it gives the poor designer/maker more options for making errors. :-) Yes, I can see that it does but, as someone else has said, the cost of fitting and manually wiring up an analogue pot is likely to be greater than the cost of the necessary digital components on a PCB. FWIW, I've had a fair amount of (mild) grief myself from carbon volume and tone pots - not to mention hard-wired input selector switches!! When these buggers play up it is a serious inconvenience (especially to non-DIYers) and the effects on sound quality can be quite severe - silence on one channel or the volume blasting through flat out on both, for instance!! (Been there, done all of that!!) Perhaps I'm naive, but I think the days of truly dodgy electronics are well past us. It's still possible to buy crap of course, but mostly I think we are getting more bang for our bucks than ever before and I don't think manufacturers playing in an international arena are going to risk their grip on the markets with anything too pooey....?? PCB appliances are generally pretty marvellous for what they cost these days (ever scruted a computer card or motherboard closely?) and even the latest hard-wired stuff like the Chinese valve amps seem to be of a very high standard - I remember the pics of the internals of Fleetie's amp (the first of the Chinky Cheepies in this group) and the response at the time was generally one of people being quite impressed with all the gubbins inside it. Since then, my own 'investigations' have proved that all the Chinese amps I've seen so far have been built better than I could manage myself!! (OK, not saying a lot, I know!! ;-) |
Digital volume control question....
On Sat, 20 May 2006 13:42:14 +0100, "Keith G"
wrote: "Stewart Pinkerton" wrote in message .. . On Fri, 19 May 2006 19:02:31 +0100, "Keith G" wrote: Well, I reckon a 30 wpc amp will work out at about 2 to 4 quid per watt, but the trouble is you *need* 100+ watts these days (ludicrous) and then I reckon you are looking at 5 times that sort of money *at least* for similar (construction/appearance/appointments) 'assembly line' amps....?? Untrue for subs, Keith. You can buy a 500 watt 'plate' amp with active crossover and all necessary connections and controls, for less then three hundred quid. Just the job for getting deep, clean bass down to 20Hz at decent SPLs from an 18" cube. Also one of the last remaining areas where the home builder can beat the commercial stuff. The thing with home builders is that just about all of them think they are beating the commercial stuff or I guess they wouldn't bother?? But it's not all about the money - many DIYers are looking to beat commercial stuff in terms of ultimate performance/specification and are well aware they would definitely *not* be beating commercial producers on a cost basis if their own labour was priced into the equation....!!?? Still true in absolute terms. DIY satisfaction has a lot of clout, but in the real world, home-built full-range speakers can in no way compete with good commercial equivalents. All else is wishful thinking. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
Digital volume control question....
On Sat, 20 May 2006 18:45:18 +0100, Adrian C
wrote: Keith G wrote: The thing with home builders is that just about all of them think they are beating the commercial stuff or I guess they wouldn't bother?? But it's not all about the money - many DIYers are looking to beat commercial stuff in terms of ultimate performance/specification and are well aware they would definitely *not* be beating commercial producers on a cost basis if their own labour was priced into the equation....!!?? Some people want to climb a mountain because it is there. The people that put a wall around that idea don't understand the enjoyment one gets in making the journey - no matter how ill looking the end looks (or not!) Sure they do - but they also understand that a home-built car will not win at Le Mans............. I take my hat off to this person and many like her. http://en.wikipedia.org/wiki/Jeri_Ellsworth DIY electronics rules forever! Kudos to a fine example of the best of US 'can do' thinking, but note that she now works as a 'consultant'............. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
Digital volume control question....
On Sat, 20 May 2006 19:04:17 +0100, Serge Auckland
wrote: Adrian C wrote: Keith G wrote: The thing with home builders is that just about all of them think they are beating the commercial stuff or I guess they wouldn't bother?? But it's not all about the money - many DIYers are looking to beat commercial stuff in terms of ultimate performance/specification and are well aware they would definitely *not* be beating commercial producers on a cost basis if their own labour was priced into the equation....!!?? Some people want to climb a mountain because it is there. The people that put a wall around that idea don't understand the enjoyment one gets in making the journey - no matter how ill looking the end looks (or not!) I take my hat off to this person and many like her. http://en.wikipedia.org/wiki/Jeri_Ellsworth DIY electronics rules forever! Absolutely! Like many of my generation I got into electronics through the DIY route, trailing round the component shops in Lisle St in London, falling over the ladies of the night in our search for some particular component! Sadly, now, just buying components is a trial in itself. It has to be mail-order or forget it. One notable exception is the wonderful emporium of Gee's in Cambridge. A real old-fashioned component shop staffed by a great guy who's been there since Schottky was a lad. Sadly building one's own stuff from scratch is a lot more expensive than buying it built. Stewart mentioned buying plate amplifiers for sub-woofers, which is fine, but if you want to make your own amplifiers you end up spending a lot more than buying one. Keith's own experience with the POS amplifiers shows this up well. There's no way you can even buy the box for the price of the complete unit from Comet, Argos or whoever. I hope there will always be a DIY sector interested in building stiff not because it's cheaper but because it's a lot more satisfying. Indeed it is - been there done that lotsa times. However, in the 21st century, it can *not* get you better performance. -- Stewart Pinkerton | Music is Art - Audio is Engineering |
Digital volume control question....
In article , Keith G
wrote: "Jim Lesurf" wrote in message ... Yes, I'd agree. I was just pointing out that some people have an aversion to anything 'digital', They *do*....??? (How strange!! ;-) Well, you said it... :-) FWIW, I've had a fair amount of (mild) grief myself from carbon volume and tone pots - not to mention hard-wired input selector switches!! So have I, mainly due to a willingness to use quite 'old' equipment at times. However I'd hope that any decent audio equipment made in recent decades would be using the newer materials which don't degrade or cause problems as in days of yore... :-) When these buggers play up it is a serious inconvenience (especially to non-DIYers) and the effects on sound quality can be quite severe - silence on one channel or the volume blasting through flat out on both, for instance!! (Been there, done all of that!!) I can recall days when the advice you might get would be to use '3-in-1 oil' to 'mend' a duff carbon pot. :-) However for some time now, unless you are using very old (or cheap) items nothing like this should arise. Perhaps I'm naive, but I think the days of truly dodgy electronics are well past us. It would be nice to think so. I also hope for peace and the end of poverty, too... :-) It's still possible to buy crap of course, but mostly I think we are getting more bang for our bucks than ever before and I don't think manufacturers playing in an international arena are going to risk their grip on the markets with anything too pooey....?? Having a world market actually helps those who wish to flog duff or counterfeit or out-of-spec goods. They can keep changing brand name or market, or simply fake/falsify things... If you read IEEE Spectrum you would be aware that this is now a very serious problem, and one that is quite hard to deal with. Yes, there are lots of good quality. cheap, items on sale. But in with it will be items using second-hand or faked components, and/or made with no real regard for actual performance beyond the point of sale. Having a well known brand name on the box may well help. But even that may not in some cases since they may have bought in faked components without knowing so. Slainte, Jim -- Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html |
Digital volume control question....
Stewart Pinkerton
But it's not all about the money - many DIYers are looking to beat commercial stuff in terms of ultimate performance/specification and are well aware they would definitely *not* be beating commercial producers on a cost basis if their own labour was priced into the equation....!!?? Still true in absolute terms. DIY satisfaction has a lot of clout, but in the real world, home-built full-range speakers can in no way compete with good commercial equivalents. All else is wishful thinking. Now you've gone too far. DIYers may not be able to produce an equivalent speaker as cheaply as a commercial one, but every commercial speaker can be improved. DIY for economy is mostly dead everywhere, not just in electronics. Unless you include kits. DIY now is about quality and style. The designers of "good commercial" speakers are constrained in part by commercial considerations peculiar to factory production. For every speaker they make, some ideals will be sacrificed to those constraints. It follows that those designers could produce better speakers if the constraints were removed. They could, given sufficient resources, DIY better than their own commercial products. Stupid DIYers with insufficient resources have *never* been able to compete with commercial products. But what about kits? Clever DIYers with sufficient resources will *always* be able to compete in terms of quality and fit-for-purpose. Eventually. Time is a problem, I have to admit. In the case of Le Mans, by the time I built the car that would have won in 1970, it was 2002. cheers, Ian |
Digital volume control question....
On Mon, 22 May 2006 11:58:24 GMT, "Ian Iveson"
wrote: Now you've gone too far. DIYers may not be able to produce an equivalent speaker as cheaply as a commercial one, but every commercial speaker can be improved. DIY for economy is mostly dead everywhere, not just in electronics. Unless you include kits. DIY now is about quality and style. No, commercial speakers *have* been improved. That is the point They are the product of careful initial design, then redesign and tweaking both in anechoic chambers and real listening rooms. That is a luxury most don't have for diy. They build one set, then live with the result. The chances of a happy result of being better than the commercial equivalent are vanishingly close to zero. d -- Pearce Consulting http://www.pearce.uk.com |
Digital volume control question....
"Stewart Pinkerton" wrote in message ... On Sat, 20 May 2006 18:45:18 +0100, Adrian C wrote: Keith G wrote: The thing with home builders is that just about all of them think they are beating the commercial stuff or I guess they wouldn't bother?? But it's not all about the money - many DIYers are looking to beat commercial stuff in terms of ultimate performance/specification and are well aware they would definitely *not* be beating commercial producers on a cost basis if their own labour was priced into the equation....!!?? Some people want to climb a mountain because it is there. The people that put a wall around that idea don't understand the enjoyment one gets in making the journey - no matter how ill looking the end looks (or not!) Sure they do - but they also understand that a home-built car will not win at Le Mans............. Bit disappointing from an engineer - why ever not, if it was built by someone with the same (or better) expertise and resources as the 'professionals'....??? (I believe it happens from time to time in the motorcycle world on possibly lesser events than the WSB, but I can't call up and specific examples - a bit of Googling might come up with summat??) |
Digital volume control question....
"Don Pearce" wrote in message ... On Mon, 22 May 2006 11:58:24 GMT, "Ian Iveson" wrote: Now you've gone too far. DIYers may not be able to produce an equivalent speaker as cheaply as a commercial one, but every commercial speaker can be improved. DIY for economy is mostly dead everywhere, not just in electronics. Unless you include kits. DIY now is about quality and style. No, commercial speakers *have* been improved. That is the point They are the product of careful initial design, then redesign and tweaking both in anechoic chambers and real listening rooms. That is a luxury most don't have for diy. They build one set, then live with the result. The chances of a happy result of being better than the commercial equivalent are vanishingly close to zero. Absolutely not the case. DIY speaker builders almost invariably build more than one pair of speakers - I know diddley doo about it all, but even I'm on my fifth pair! (Two of which are/have been for other people!) Also, I believe many DIYers will spend quite a bit of time tweaking a a pair of speakers after they have been built, before they consider them *finished*. Where DIY speaker builders differ from a commercial enterprise is that they tend to tweak (different drivers and other components in the case of speakers with crossovers) in the actual room they are going to use the speakers in and using kit they already own. My own speakers already sound better than a number of commercial pairs I have here, which have never suited the room! I double-checked this only a day or two ago - my Pinkies are *consummately* better in my room than a pair of very respectable JM-Labs floorstanders (and a pair of even more respectable Ruarks) I have here. Until you hit the 'sky's the limit' for price (Wilson &c.?) all speakers are built to a price and it's common knowledge that 70/80 % of the costs of a pair of speakers (before marketting and advertising &c. are added in) go into the cabinet. A DIYer has the option to spend the money on the *sound quality* - where it counts. All this proclaiming that DIY can't beat commercial is just so much dogma - any DIYer with sufficient skill/talent/expertise/resources and *funds* can match the commercial sector in just about any field if he chooses to. Most commercial enterprises had small, domestic beginnings from what I can see of it, anyway!! |
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