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Opinion needed re power amp building
I am looking to build an amp for home theatre/hifi use.
currently have an amp using Hitachi's default design for mos fets from the '80's ( 2sk49 2sj50 I think ). It is used with a tagmclaren av32r and ipl acoustics tl4 speakers at the front and Ariston ( small black tubular things that sound quite good ) at the back. I plan using LM4702 but have three options for the output stage. bipolar SAP15P and SAP15N 2SA1943 and 2SC5200 mosfet 2SK1530 and 2SJ201 I know I'm inviting WW3 but would there be any differance in sound between them ? Pete |
Opinion needed re power amp building
In article , Pete
wrote: I am looking to build an amp for home theatre/hifi use. currently have an amp using Hitachi's default design for mos fets from the '80's ( 2sk49 2sj50 I think ). It is used with a tagmclaren av32r and ipl acoustics tl4 speakers at the front and Ariston ( small black tubular things that sound quite good ) at the back. I plan using LM4702 but have three options for the output stage. bipolar SAP15P and SAP15N 2SA1943 and 2SC5200 mosfet 2SK1530 and 2SJ201 I know I'm inviting WW3 but would there be any differance in sound between them ? No need for WW3 since no meaningful answer is possible without knowing the actual details of the designs which use them, and more info on the use. :-) The main thing you could tell from the above is the max power / current / voltage you might be able to drive. But if that is 'sufficient' for your speakers and listening level that becomes irrelevant to the choice. If the SAP devices are of the type that are darlingtons with the internal thermal compensation diodes, then they may make thermal stability easier. But I personally never liked darlingtons or power fets as I found they tended to be prone to ultrasonic hooting. But YMMV. The SAP and mosfets can make driving and biassing easier. That said I am old fashioned so am most comfortable with using simple bipolar output devices. Slainte, Jim -- Please use the address on the audiomisc page if you wish to email me. Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html Audio Misc http://www.audiomisc.co.uk/index.html |
Opinion needed re power amp building
"Pete" wrote in message
... I am looking to build an amp for home theatre/hifi use. currently have an amp using Hitachi's default design for mos fets from the '80's ( 2sk49 2sj50 I think ). It is used with a tagmclaren av32r and ipl acoustics tl4 speakers at the front and Ariston ( small black tubular things that sound quite good ) at the back. I plan using LM4702 but have three options for the output stage. bipolar SAP15P and SAP15N 2SA1943 and 2SC5200 mosfet 2SK1530 and 2SJ201 I know I'm inviting WW3 but would there be any differance in sound between them ? Pete Why bother? The basic Hitachi design is as good as it gets. You can improve things by building aproper regulated power supply for it. Mine, on Ambit boards, was dual mono with regulated PSUs designed by John Lindsey Hood would do about 112W at the onset of limiting into 8R and 224W at the onset of limiting into 4R. In 'normal' use it barely got warm. It was as flat as a pancake (OK +/- 0.2dB) from about 12Hz to well over 100KHz, with maximum phase error of about 2 deg at 12Hz and about 80KHz. Surely that's good enough for anybody? -- Woody harrogate three at ntlworld dot com |
Opinion needed re power amp building
"Pete" wrote in message ... I am looking to build an amp for home theatre/hifi use. currently have an amp using Hitachi's default design for mos fets from the '80's ( 2sk49 2sj50 I think ). It is used with a tagmclaren av32r and ipl acoustics tl4 speakers at the front and Ariston ( small black tubular things that sound quite good ) at the back. I plan using LM4702 but have three options for the output stage. bipolar SAP15P and SAP15N 2SA1943 and 2SC5200 mosfet 2SK1530 and 2SJ201 I know I'm inviting WW3 but would there be any differance in sound between them ? **Depends on implementation. The MOSFETs, of course, will always sound like MOSFETs - dull, boring, undynamic and compressed. The 2SA1943/2SC5200 devices are amongst the most advanced, lowest distortion output devices developed. The SAP15s are easy and convenient to implement, but you run the risk of using a device unique to a single manufacturer. Once that manufacturer deletes them from the product line-up, you'll be screwed for spare parts later on. Personally, I like the 2SA1943/2SC5200 devices, Collectors coupled to the load. -- Trevor Wilson www.rageaudio.com.au |
Opinion needed re power amp building
On Wed, 4 Nov 2009 07:06:02 +1100, "Trevor Wilson"
wrote: "Pete" wrote in message ... I am looking to build an amp for home theatre/hifi use. currently have an amp using Hitachi's default design for mos fets from the '80's ( 2sk49 2sj50 I think ). It is used with a tagmclaren av32r and ipl acoustics tl4 speakers at the front and Ariston ( small black tubular things that sound quite good ) at the back. I plan using LM4702 but have three options for the output stage. bipolar SAP15P and SAP15N 2SA1943 and 2SC5200 mosfet 2SK1530 and 2SJ201 I know I'm inviting WW3 but would there be any differance in sound between them ? **Depends on implementation. The MOSFETs, of course, will always sound like MOSFETs - dull, boring, undynamic and compressed. The 2SA1943/2SC5200 devices are amongst the most advanced, lowest distortion output devices developed. The SAP15s are easy and convenient to implement, but you run the risk of using a device unique to a single manufacturer. Once that manufacturer deletes them from the product line-up, you'll be screwed for spare parts later on. Personally, I like the 2SA1943/2SC5200 devices, Collectors coupled to the load. Compressed? You can of course produce a transfer characteristic to back this up? As far as I am aware it is perfectly possible to produce a MOSFET design without a trace of compression - which would of course show up as an unimaginably huge distortion figure. d |
Opinion needed re power amp building
"Don Pearce" wrote in message ... On Wed, 4 Nov 2009 07:06:02 +1100, "Trevor Wilson" wrote: "Pete" wrote in message .. . I am looking to build an amp for home theatre/hifi use. currently have an amp using Hitachi's default design for mos fets from the '80's ( 2sk49 2sj50 I think ). It is used with a tagmclaren av32r and ipl acoustics tl4 speakers at the front and Ariston ( small black tubular things that sound quite good ) at the back. I plan using LM4702 but have three options for the output stage. bipolar SAP15P and SAP15N 2SA1943 and 2SC5200 mosfet 2SK1530 and 2SJ201 I know I'm inviting WW3 but would there be any differance in sound between them ? **Depends on implementation. The MOSFETs, of course, will always sound like MOSFETs - dull, boring, undynamic and compressed. The 2SA1943/2SC5200 devices are amongst the most advanced, lowest distortion output devices developed. The SAP15s are easy and convenient to implement, but you run the risk of using a device unique to a single manufacturer. Once that manufacturer deletes them from the product line-up, you'll be screwed for spare parts later on. Personally, I like the 2SA1943/2SC5200 devices, Collectors coupled to the load. Compressed? **Yep. You can of course produce a transfer characteristic to back this up? **Negative Tempco of gm. As far as I am aware it is perfectly possible to produce a MOSFET design without a trace of compression - which would of course show up as an unimaginably huge distortion figure. **What can I say? It what they sound like, when operating in low bias Class A/B. When operating in high bias Class A/B or Class A, they show no signs of compression. At low currents, they suck. Ask anyone who has taken the time to do a double blind listen. I have. Many times. Shockers. -- Trevor Wilson www.rageaudio.com.au |
Opinion needed re power amp building
"Trevor Wilson" wrote in
message **Depends on implementation. The MOSFETs, of course, will always sound like MOSFETs - dull, boring, undynamic and compressed. Sounds like more of the same "every amplifier sounds different religion that Trevor has been entertaining many of with for years and years. It wasn't that long ago that Trevor was making similar claims about power amps with that well-known circuit design *failing* known as loop feedback. So Trevor, which is worse, MOSFETs with or without loop feedback, versus bipolars with or without loop feedback? |
Opinion needed re power amp building
On Wed, 4 Nov 2009 07:52:21 +1100, "Trevor Wilson"
wrote: "Don Pearce" wrote in message ... On Wed, 4 Nov 2009 07:06:02 +1100, "Trevor Wilson" wrote: "Pete" wrote in message . .. I am looking to build an amp for home theatre/hifi use. currently have an amp using Hitachi's default design for mos fets from the '80's ( 2sk49 2sj50 I think ). It is used with a tagmclaren av32r and ipl acoustics tl4 speakers at the front and Ariston ( small black tubular things that sound quite good ) at the back. I plan using LM4702 but have three options for the output stage. bipolar SAP15P and SAP15N 2SA1943 and 2SC5200 mosfet 2SK1530 and 2SJ201 I know I'm inviting WW3 but would there be any differance in sound between them ? **Depends on implementation. The MOSFETs, of course, will always sound like MOSFETs - dull, boring, undynamic and compressed. The 2SA1943/2SC5200 devices are amongst the most advanced, lowest distortion output devices developed. The SAP15s are easy and convenient to implement, but you run the risk of using a device unique to a single manufacturer. Once that manufacturer deletes them from the product line-up, you'll be screwed for spare parts later on. Personally, I like the 2SA1943/2SC5200 devices, Collectors coupled to the load. Compressed? **Yep. You can of course produce a transfer characteristic to back this up? **Negative Tempco of gm. As far as I am aware it is perfectly possible to produce a MOSFET design without a trace of compression - which would of course show up as an unimaginably huge distortion figure. **What can I say? It what they sound like, when operating in low bias Class A/B. When operating in high bias Class A/B or Class A, they show no signs of compression. At low currents, they suck. Ask anyone who has taken the time to do a double blind listen. I have. Many times. Shockers. Negative tempco makes no difference. The gain of a power amplifier is set by a pair of feedback resistors. Provided there is sufficient open loop gain available (and we must assume there is) there can be no compression. The system will perform at constant gain up to the clipping point just like any amplifier. I presume you are treating this as an interview for a job reviewing in Stereophile? d |
Opinion needed re power amp building
"Don Pearce" wrote in message ... On Wed, 4 Nov 2009 07:52:21 +1100, "Trevor Wilson" wrote: "Don Pearce" wrote in message ... On Wed, 4 Nov 2009 07:06:02 +1100, "Trevor Wilson" wrote: "Pete" wrote in message .. . I am looking to build an amp for home theatre/hifi use. currently have an amp using Hitachi's default design for mos fets from the '80's ( 2sk49 2sj50 I think ). It is used with a tagmclaren av32r and ipl acoustics tl4 speakers at the front and Ariston ( small black tubular things that sound quite good ) at the back. I plan using LM4702 but have three options for the output stage. bipolar SAP15P and SAP15N 2SA1943 and 2SC5200 mosfet 2SK1530 and 2SJ201 I know I'm inviting WW3 but would there be any differance in sound between them ? **Depends on implementation. The MOSFETs, of course, will always sound like MOSFETs - dull, boring, undynamic and compressed. The 2SA1943/2SC5200 devices are amongst the most advanced, lowest distortion output devices developed. The SAP15s are easy and convenient to implement, but you run the risk of using a device unique to a single manufacturer. Once that manufacturer deletes them from the product line-up, you'll be screwed for spare parts later on. Personally, I like the 2SA1943/2SC5200 devices, Collectors coupled to the load. Compressed? **Yep. You can of course produce a transfer characteristic to back this up? **Negative Tempco of gm. As far as I am aware it is perfectly possible to produce a MOSFET design without a trace of compression - which would of course show up as an unimaginably huge distortion figure. **What can I say? It what they sound like, when operating in low bias Class A/B. When operating in high bias Class A/B or Class A, they show no signs of compression. At low currents, they suck. Ask anyone who has taken the time to do a double blind listen. I have. Many times. Shockers. Negative tempco makes no difference. The gain of a power amplifier is set by a pair of feedback resistors. Provided there is sufficient open loop gain available (and we must assume there is) there can be no compression. The system will perform at constant gain up to the clipping point just like any amplifier. I presume you are treating this as an interview for a job reviewing in Stereophile? **I doubt that. I have been critical of Stereophile many times. I have also performed several DBTs involving MOSFET amps and BJT amps. The first was way back when Perreaux first burst onto the scene with their MOSFET amps. I wondered at what I was hearing, so I set up a Phase Linear 400 amp for comparison. The Phase Linear was determined (not just by me) to be much more dynamic sounding. The only MOSFET amps I've heard which do not suffer this problem are those manufactured by Pass Labs. Tell me about your blind listening experiences with MOSFET amps and BJT amps. -- Trevor Wilson www.rageaudio.com.au |
Opinion needed re power amp building
On Wed, 4 Nov 2009 08:32:19 +1100, "Trevor Wilson"
wrote: "Don Pearce" wrote in message ... On Wed, 4 Nov 2009 07:52:21 +1100, "Trevor Wilson" wrote: "Don Pearce" wrote in message ... On Wed, 4 Nov 2009 07:06:02 +1100, "Trevor Wilson" wrote: "Pete" wrote in message . .. I am looking to build an amp for home theatre/hifi use. currently have an amp using Hitachi's default design for mos fets from the '80's ( 2sk49 2sj50 I think ). It is used with a tagmclaren av32r and ipl acoustics tl4 speakers at the front and Ariston ( small black tubular things that sound quite good ) at the back. I plan using LM4702 but have three options for the output stage. bipolar SAP15P and SAP15N 2SA1943 and 2SC5200 mosfet 2SK1530 and 2SJ201 I know I'm inviting WW3 but would there be any differance in sound between them ? **Depends on implementation. The MOSFETs, of course, will always sound like MOSFETs - dull, boring, undynamic and compressed. The 2SA1943/2SC5200 devices are amongst the most advanced, lowest distortion output devices developed. The SAP15s are easy and convenient to implement, but you run the risk of using a device unique to a single manufacturer. Once that manufacturer deletes them from the product line-up, you'll be screwed for spare parts later on. Personally, I like the 2SA1943/2SC5200 devices, Collectors coupled to the load. Compressed? **Yep. You can of course produce a transfer characteristic to back this up? **Negative Tempco of gm. As far as I am aware it is perfectly possible to produce a MOSFET design without a trace of compression - which would of course show up as an unimaginably huge distortion figure. **What can I say? It what they sound like, when operating in low bias Class A/B. When operating in high bias Class A/B or Class A, they show no signs of compression. At low currents, they suck. Ask anyone who has taken the time to do a double blind listen. I have. Many times. Shockers. Negative tempco makes no difference. The gain of a power amplifier is set by a pair of feedback resistors. Provided there is sufficient open loop gain available (and we must assume there is) there can be no compression. The system will perform at constant gain up to the clipping point just like any amplifier. I presume you are treating this as an interview for a job reviewing in Stereophile? **I doubt that. I have been critical of Stereophile many times. I have also performed several DBTs involving MOSFET amps and BJT amps. The first was way back when Perreaux first burst onto the scene with their MOSFET amps. I wondered at what I was hearing, so I set up a Phase Linear 400 amp for comparison. The Phase Linear was determined (not just by me) to be much more dynamic sounding. The only MOSFET amps I've heard which do not suffer this problem are those manufactured by Pass Labs. Tell me about your blind listening experiences with MOSFET amps and BJT amps. We're discussing compression, which can be measured objectively - please don't try to divert the discussion onto the metaphysical. Show me compression. d |
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