Digital volume control question....
 

"Ian Iveson" wrote in message
. uk...
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.


And difference (choice) - the only commercial fullrange speakers I can think
of offhand are the Zu Druids for about 2.5K!! (After that it's Jim Carfrae's
'homebrew horns' at up to about 18K a pair!! ;-)

Digital volume control question....
 

"Stewart Pinkerton" wrote


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.


No, give at least some of us credit for having the honesty to pack an idea
in if we thought we were ****ing in the breeze!

When my mate Pat (the ****) came round to hear my Pinkies for the first time
his *immediate* reaction was 'Woah! You'd have to spend a lot of money to
that kind of sound!"

As I said to Don just now - I cut a pair of (£500) JM-Labs in the other day
to *double check*, my Pinkies (sorry!! ;-) beat the crap out of them with
the possible exception of a crisper bass, but the comparative overall
'flatness' of the sound was unbearable! (That was on a sandamp - put them on
valves and the 'firewood horns' really shine!! ;-)

Incidentally, the name 'fullrange' is one of convenience - nobody I know
considers them to have the same bass extension as some of the bigger/better
mutliway speakers. Treble is another story - I've yet to encounter 'normal'
speakers with the extent and sweetness of treble that you get with Fostex
drivers, at least!!

Digital volume control question....
 

On Mon, 22 May 2006 14:28:25 +0100, "Keith G"
wrote:


"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!!



But your new builds haven't been evolutions, have they. You haven't
assessed a speaker, done some sums and thought "I think the horn may
work better if it is three inches longer", then built and evaluated.
What you have built is several different designs. That isn't
development.

d

--
Pearce Consulting
http://www.pearce.uk.com

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', 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.


*Stop press*

I have detected a little artifact in the sound from the Argos stuff this
morning - not audible in normal use (even right up to the speaker), but when
playing back *recordings* and trying to record them with a little mic
there's a little 'whumpa whumpa whumpa' going on at about once every second
(or so) at quite a low level....???

It's here at about 600K:

http://www.apah69.dsl.pipex.com/show/wumpa.mp3


Although the mic is a bit suspect I think I have also heard it when playing
back recordings from my PVR but I couldn't replicate it just now....???

Digital volume control question....
 

"Don Pearce" wrote in message
...
On Mon, 22 May 2006 14:28:25 +0100, "Keith G"
wrote:


"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!!



But your new builds haven't been evolutions, have they. You haven't
assessed a speaker, done some sums and thought "I think the horn may
work better if it is three inches longer", then built and evaluated.
What you have built is several different designs. That isn't
development.


Hmm, I'm not talking about *designing & developing* - I'm really only
talking about *building*.

Most DIYers build an established and proven design - some will tweak, some
won't. Some will go on to design completely new stuff themselves - that's
how it goes and is one of the reasons DIYing is a Good Thing.

Myself, I have constructed the various 'established design' cabinets (quite
accurately) and have experimented with different drivers (Fostex and
Visaton) and played about with stuffing and bits of carpet (as you do), but
I don't have the knowledge (or will or time or money) to get into
*designing* per se!! Having said that, I have *extended* the design on the
last pair (on a 'suck it and see' basis) and appear to be getting away with
it!! :-)

It's too easy to dismiss DIY activity as folly in the face of modern
commercial offerings and I'd be the first to admit that there's some good
stuff at very reasonable prices out there, but consider this analogy - Mr
Kipling makes exceedingly good cakes (says so on the packet) but, if you
are/were lucky, yer auld mum could beat him hands down every time!! (When my
mum signed off steak and kidney pudding vanished *forever* from the face of
the planet, AFAIAC!!)

It's a mistake to think most DIYers are dozy chancers like me - there's a
great deal deal of real experience and expertise out there and which seems
to be freely shared and passed around. Even my numpty efforts attract a post
or three every week - along the lines of this one (received yesterday):


"Hi keith, a really nice friendly website.

Congratulations. I've ordered a pair of tangband 317s with a view to
making some needles myself. However I'm completely new to speaker
building so your descriptions are very welcome. You imply that some
places will cut to size ? Could you literally come away with a kit of
parts ? Failing that it looks like the minimum tools I'd need would be
a circular saw & router."


(OK, I've put him right on the circular saw and router....!! ;-)

Telling people like this 'don't bother, it ain't worth it' does nothing to
further the cause or the quest for Audio Nirvana. *Even if* someone's
speakers were actually crap in reality but they liked and *preferred* them,
then their efforts would have been worthwhile. If my own efforts were/had
been crap, trust me, the 'listeners' I've had round here would have damn
soon told me so!! (You know how it is!! ;-)

Digital volume control question....
 

On Mon, 22 May 2006 15:11:47 +0100, "Keith G"
wrote:

*Stop press*

I have detected a little artifact in the sound from the Argos stuff this
morning - not audible in normal use (even right up to the speaker), but when
playing back *recordings* and trying to record them with a little mic
there's a little 'whumpa whumpa whumpa' going on at about once every second
(or so) at quite a low level....???

It's here at about 600K:

http://www.apah69.dsl.pipex.com/show/wumpa.mp3

Exactly once per second by the look of it. Does it have a clock, or
could this correspond to the update rate of the display?

d

--
Pearce Consulting
http://www.pearce.uk.com

Digital volume control question....
 

On Mon, 22 May 2006 15:42:53 +0100, "Keith G"
wrote:

But your new builds haven't been evolutions, have they. You haven't
assessed a speaker, done some sums and thought "I think the horn may
work better if it is three inches longer", then built and evaluated.
What you have built is several different designs. That isn't
development.


Hmm, I'm not talking about *designing & developing* - I'm really only
talking about *building*.

Most DIYers build an established and proven design - some will tweak, some
won't. Some will go on to design completely new stuff themselves - that's
how it goes and is one of the reasons DIYing is a Good Thing.

Myself, I have constructed the various 'established design' cabinets (quite
accurately) and have experimented with different drivers (Fostex and
Visaton) and played about with stuffing and bits of carpet (as you do), but
I don't have the knowledge (or will or time or money) to get into
*designing* per se!! Having said that, I have *extended* the design on the
last pair (on a 'suck it and see' basis) and appear to be getting away with
it!! :-)

It's too easy to dismiss DIY activity as folly in the face of modern
commercial offerings and I'd be the first to admit that there's some good
stuff at very reasonable prices out there, but consider this analogy - Mr
Kipling makes exceedingly good cakes (says so on the packet) but, if you
are/were lucky, yer auld mum could beat him hands down every time!! (When my
mum signed off steak and kidney pudding vanished *forever* from the face of
the planet, AFAIAC!!)

It's a mistake to think most DIYers are dozy chancers like me - there's a
great deal deal of real experience and expertise out there and which seems
to be freely shared and passed around. Even my numpty efforts attract a post
or three every week - along the lines of this one (received yesterday):


"Hi keith, a really nice friendly website.

Congratulations. I've ordered a pair of tangband 317s with a view to
making some needles myself. However I'm completely new to speaker
building so your descriptions are very welcome. You imply that some
places will cut to size ? Could you literally come away with a kit of
parts ? Failing that it looks like the minimum tools I'd need would be
a circular saw & router."


(OK, I've put him right on the circular saw and router....!! ;-)

Telling people like this 'don't bother, it ain't worth it' does nothing to
further the cause or the quest for Audio Nirvana. *Even if* someone's
speakers were actually crap in reality but they liked and *preferred* them,
then their efforts would have been worthwhile. If my own efforts were/had
been crap, trust me, the 'listeners' I've had round here would have damn
soon told me so!! (You know how it is!! ;-)


All too well. For myself, I have taken what is probably the commonest
compromise path these days. I have professionally built speakers
(Sonus Faber Amators), and a home-built sub. There is no alternative
to home building for this sub because it is built into a concrete
under-stairs cupboard space. As such it has a huge internal volume and
works in effectively infinite baffle mode. This makes it very
non-boomy - musical in fact. It also goes very, very low in frequency.
It does need quite a few of those "expensive" watts, though ;-)

d

--
Pearce Consulting
http://www.pearce.uk.com

Digital volume control question....
 

"Don Pearce" wrote in message
...
On Mon, 22 May 2006 15:11:47 +0100, "Keith G"
wrote:

*Stop press*

I have detected a little artifact in the sound from the Argos stuff this
morning - not audible in normal use (even right up to the speaker), but
when
playing back *recordings* and trying to record them with a little mic
there's a little 'whumpa whumpa whumpa' going on at about once every
second
(or so) at quite a low level....???

It's here at about 600K:

http://www.apah69.dsl.pipex.com/show/wumpa.mp3

Exactly once per second by the look of it. Does it have a clock, or
could this correspond to the update rate of the display?


???

No idea! But it doesn't have a clock. I'm sure I've heard this noise on some
PVR playback and then when I tried to record 'open mic', otherwise I hadn't
noticed it!!

Here's another one - I have a Hauppage WinTV card in this machine and have
just tried to install the crappy software (WinTV2000!!??) that came with it.
I might have aerial issues (whenever not?) but is there any better software
available to use with this card before I start crawling about in the loft? I
was using ShowShifter on the old machine but seems to have gone tits up!!

Digital volume control question....
 

On Mon, 22 May 2006 16:40:36 +0100, "Keith G"
wrote:

???

No idea! But it doesn't have a clock. I'm sure I've heard this noise on some
PVR playback and then when I tried to record 'open mic', otherwise I hadn't
noticed it!!


The open mic thing is bothering me a bit. The frequency does seem very
low to be picked up by a mic. Are you sure this isn't being generated
in the mic circuit side of things rather than the Argos box? Or with
the wick wound up, can you see the speaker cones jumping in time with
the sound?

Here's another one - I have a Hauppage WinTV card in this machine and have
just tried to install the crappy software (WinTV2000!!??) that came with it.
I might have aerial issues (whenever not?) but is there any better software
available to use with this card before I start crawling about in the loft? I
was using ShowShifter on the old machine but seems to have gone tits up!!




I bought one of those Hauppauge cards a while back - totally screwed
two PCs before I finally threw it where it belonged. It did work once
for about ten minutes, but never kept its channel list when I turned
off.

d

--
Pearce Consulting
http://www.pearce.uk.com

Digital volume control question....
 

"Don Pearce" wrote


Telling people like this 'don't bother, it ain't worth it' does nothing to
further the cause or the quest for Audio Nirvana. *Even if* someone's
speakers were actually crap in reality but they liked and *preferred*
them,
then their efforts would have been worthwhile. If my own efforts were/had
been crap, trust me, the 'listeners' I've had round here would have damn
soon told me so!! (You know how it is!! ;-)


All too well. For myself, I have taken what is probably the commonest
compromise path these days. I have professionally built speakers
(Sonus Faber Amators), and a home-built sub. There is no alternative
to home building for this sub because it is built into a concrete
under-stairs cupboard space. As such it has a huge internal volume and
works in effectively infinite baffle mode. This makes it very
non-boomy - musical in fact. It also goes very, very low in frequency.
It does need quite a few of those "expensive" watts, though ;-)


I don't need a sub for music, but then I've never really had a decent one!!
(We don't even use one on the Cinema setup, the afore-mentioned Ruarks do a
pretty good job without one.)

Digital volume control question....
 

"Don Pearce" wrote in message
...
On Mon, 22 May 2006 16:40:36 +0100, "Keith G"
wrote:

???

No idea! But it doesn't have a clock. I'm sure I've heard this noise on
some
PVR playback and then when I tried to record 'open mic', otherwise I
hadn't
noticed it!!


The open mic thing is bothering me a bit. The frequency does seem very
low to be picked up by a mic. Are you sure this isn't being generated
in the mic circuit side of things rather than the Argos box?


If I didn't 'recognise' the sound from when I was playing back PVR
recordings (I'm sure I do) I'd think *mic* straightaway - it ain't right and
(I think) doesn't work properly in 'stereo' anyway. I'll have to check it
out, but see below...


Or with
the wick wound up, can you see the speaker cones jumping in time with
the sound?


No.



Here's another one - I have a Hauppage WinTV card in this machine and have
just tried to install the crappy software (WinTV2000!!??) that came with
it.
I might have aerial issues (whenever not?) but is there any better
software
available to use with this card before I start crawling about in the loft?
I
was using ShowShifter on the old machine but seems to have gone tits up!!




I bought one of those Hauppauge cards a while back - totally screwed
two PCs before I finally threw it where it belonged.


Hah!!


It did work once
for about ten minutes, but never kept its channel list when I turned
off.


....I have ****ed so much time away on this POS I feel nauseous!

Sandwiched between this poxy thing and the truly *appalling* weather, I
would have done summat totally different (and a damn sight more
productive/useful) today, if I had known how it was going to go!!

Digital volume control question....
 

"Jim Lesurf" wrote in message
...
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. :-)


That'll be 'WD40' now!! :-)


However for some time now, unless
you are using very old (or cheap) items nothing like this should arise.


Put me down for the 'cheap' option!!



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... :-)



Well, ****e PC TV cards aside (actually, it's the software) I hafta say I
find most things work pretty well most of the time. I can remember the (B&W)
days when you sat just waiting for the 'tube' to go on your telly!! :-)


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 fake *everything* is a big problem these days! I trust in 'respectable'
suppliers and the 12 months warranty that comes from them. usually. I don't
buy extra warranty - who TH wants 'electronics' to last 3 years these days?
Most of it it has been superceded by the time you get it home!!



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.


Sure.

Digital volume control question....
 

On Mon, 22 May 2006 17:02:44 +0100, "Keith G"
wrote:

All too well. For myself, I have taken what is probably the commonest
compromise path these days. I have professionally built speakers
(Sonus Faber Amators), and a home-built sub. There is no alternative
to home building for this sub because it is built into a concrete
under-stairs cupboard space. As such it has a huge internal volume and
works in effectively infinite baffle mode. This makes it very
non-boomy - musical in fact. It also goes very, very low in frequency.
It does need quite a few of those "expensive" watts, though ;-)


I don't need a sub for music, but then I've never really had a decent one!!
(We don't even use one on the Cinema setup, the afore-mentioned Ruarks do a
pretty good job without one.)

I think you would be pleasantly surprised by a decent sub (not one of
those horrid little home cinema things). It is a much easier project
than a full range speaker and once you get it dialled in (turn it down
until you can't hear it, then turn it up just a bit) it really does
add to the music, particularly for speakers that don't cover the
bottom couple of octaves like your horns.

d

--
Pearce Consulting
http://www.pearce.uk.com

Digital volume control question....
 

On Mon, 22 May 2006 17:19:37 +0100, "Keith G"
wrote:

Yes fake *everything* is a big problem these days! I trust in 'respectable'
suppliers and the 12 months warranty that comes from them. usually. I don't
buy extra warranty - who TH wants 'electronics' to last 3 years these days?
Most of it it has been superceded by the time you get it home!!


A survey was done a couple of years ago of stock at Lockheed-Girling's
aircraft brakes stores. Quite a number of fake items were found. They
had been ordered, delivered, then returned to stock.

d

--
Pearce Consulting
http://www.pearce.uk.com

Digital volume control question....
 

"Don Pearce" wrote in message
...
On Mon, 22 May 2006 17:19:37 +0100, "Keith G"
wrote:

Yes fake *everything* is a big problem these days! I trust in
'respectable'
suppliers and the 12 months warranty that comes from them. usually. I
don't
buy extra warranty - who TH wants 'electronics' to last 3 years these
days?
Most of it it has been superceded by the time you get it home!!


A survey was done a couple of years ago of stock at Lockheed-Girling's
aircraft brakes stores. Quite a number of fake items were found. They
had been ordered, delivered, then returned to stock.


And I believe a bunch of 'fake' disk brakes was discovered either badged as
Ford (?) spares or simply being fitted and charged as genuine parts - when
the investigation was carried out they were found to come from the same
Eastern European factory as the 'official' versions?

Don't know that for certain - it's a hazy memory I've got but it was only a
few years back, perhaps someone knows more??

Digital volume control question....
 

"Don Pearce" wrote in message
...
On Mon, 22 May 2006 17:02:44 +0100, "Keith G"
wrote:

All too well. For myself, I have taken what is probably the commonest
compromise path these days. I have professionally built speakers
(Sonus Faber Amators), and a home-built sub. There is no alternative
to home building for this sub because it is built into a concrete
under-stairs cupboard space. As such it has a huge internal volume and
works in effectively infinite baffle mode. This makes it very
non-boomy - musical in fact. It also goes very, very low in frequency.
It does need quite a few of those "expensive" watts, though ;-)


I don't need a sub for music, but then I've never really had a decent
one!!
(We don't even use one on the Cinema setup, the afore-mentioned Ruarks do
a
pretty good job without one.)

I think you would be pleasantly surprised by a decent sub (not one of
those horrid little home cinema things). It is a much easier project
than a full range speaker and once you get it dialled in (turn it down
until you can't hear it, then turn it up just a bit) it really does
add to the music, particularly for speakers that don't cover the
bottom couple of octaves like your horns.


I would need to hear just such a 'decent' sub before I could be convinced I
needed one - I ain't heard a sub yet that wuz singing from the same hymn
sheet!!

Digital volume control question....
 

"Keith G" wrote in message
...

"Stewart Pinkerton" wrote in message
...
On Sat, 20 May 2006 18:45:18 +0100, Adrian C
wrote:

Keith G wrote:
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??)


One of these (kit cars) might do it:
http://www.ultimasports.co.uk/company/

Digital volume control question....
 

"Philip North" wrote in message
...

"Keith G" wrote in message
...

"Stewart Pinkerton" wrote in message
...
On Sat, 20 May 2006 18:45:18 +0100, Adrian C
wrote:

Keith G wrote:
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??)


One of these (kit cars) might do it:
http://www.ultimasports.co.uk/company/


'Kinell! :-)

Digital volume control question....
 

As to audio quality, a conductive plastic pot will have zero effect on
audio quality.

Here's another view from Allen Wright (designs amps)
"Vishay cermet are good. One of the biggest con acts has been the
pushing of conductive plastic pots to the audio industry. I don't care
what the brand is - if they make a CP and a cermet (or even a quality
carbon) then my experience is that the cermet KILLS the CP for sonic
quality. The VISHAY cerment (made by their french wing Sfernice))
sounds. like two good fixed resistors, the identical looking CP sounds
like ****! Allen

Digital volume control question....
 

Try to get past this 'mutual exclusivity' thing

Would be useful - modern valve amps are full of SS parts.

Digital volume control question....
 

Keith wrote

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.


And difference (choice) - the only commercial fullrange speakers I can think
of offhand are the Zu Druids for about 2.5K!! (After that it's Jim Carfrae's
'homebrew horns' at up to about 18K a pair!! ;-)

Hmm, well, er, that's a moot point for sure.

The most obvious issue here, that you might assume applies to Stewart, is that
to the reproductionist, perfection is perfection, and it is a singular ideal.
You can choose your lies, but you can't mess with truth.

Science is over, technology is done, politics is dead. But still my music
doesn't sound like I'm really there. No wonder ppl are turning to religious
fanaticism. That's a more important debate I think.

But Stewart likes a touch of euphony in his speaks. Perhaps he means that there
is enough variety available in the market that, whatever the shape of your room,
and whatever your reasonable preference, there will be something there to suit
you, and that something could not be bettered by building it yourself.

What do you mean, Stewart?

cheers, Ian

Digital volume control question....
 

In article , Keith G
wrote:

"Jim Lesurf" wrote in message
...



I don't buy extra warranty

Nor do as it is generally an over-priced con.

- who TH wants 'electronics' to last 3 years these days?

I do. :-) Although it depends on the nature of the item in question. e.g.
I would not expect a compact fluro lamp to last forever. However if I buy
something like an amplifier or loudspeakers I'd want them to work correctly
for some decades.

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....
 

Andy Evans wrote:
As to audio quality, a conductive plastic pot will have zero effect on
audio quality.

Here's another view from Allen Wright (designs amps)
"Vishay cermet are good. One of the biggest con acts has been the
pushing of conductive plastic pots to the audio industry. I don't care
what the brand is - if they make a CP and a cermet (or even a quality
carbon) then my experience is that the cermet KILLS the CP for sonic
quality. The VISHAY cerment (made by their french wing Sfernice))
sounds. like two good fixed resistors, the identical looking CP sounds
like ****! Allen

Oh dear someone else who thinks resistors have a sound.

A pot, whether cermet, conductive plastic, carbon or whatever is a pure
resistance (discounting irrelevant tiny amounts of capacitance and
inductance- wirewound pots excepted) and consequently are linear to the
limits of measurement. Therefore how any pot can be better than another
for sonic qualities is beyond me. Pots vary in the accuracy of their
law, the noise made when being altered, tracking on stereo, how long
they last before track wear is evident etc. Sonic differences are just
not there.

S.

Digital volume control question....
 

"Ian Iveson" wrote in message
.uk...
Keith wrote


And difference (choice) - the only commercial fullrange speakers I can
think of offhand are the Zu Druids for about 2.5K!! (After that it's Jim
Carfrae's 'homebrew horns' at up to about 18K a pair!! ;-)

Hmm, well, er, that's a moot point for sure.

The most obvious issue here, that you might assume applies to Stewart, is
that to the reproductionist, perfection is perfection, and it is a
singular ideal. You can choose your lies, but you can't mess with truth.


Hmmm....



Science is over,


Yes.


technology is done,


No,


politics is dead.


Yes.


But still my music doesn't sound like I'm really there.


Yes. (Never will.....)


No wonder ppl are turning to religious fanaticism.


Yes. (It's called Reality TV, football and tweaking.... ;-)


That's a more important debate I think.


Possibly!



But Stewart likes a touch of euphony in his speaks. Perhaps he means that
there is enough variety available in the market that, whatever the shape
of your room, and whatever your reasonable preference, there will be
something there to suit you, and that something could not be bettered by
building it yourself.

What do you mean, Stewart?


I think the trick is not to become too blinded by your own DIY efforts - if
the product stinks, have the honesty to admit it and redo the work or toss
it. There aren't too many reasons people get into DIY Audio - disatisfaction
with what's available 'commercially' is probably the main one, curiosity is
another and the *challenge* is another. Saving money isn't as important as
it once was, but that doesn't mean huge savings aren't possible - if you
avoid the flatpack 'commercial kits', savings on speakers can be
significant.

Digital volume control question....
 

"Serge Auckland" wrote in message
...
Andy Evans wrote:
As to audio quality, a conductive plastic pot will have zero effect on
audio quality.

Here's another view from Allen Wright (designs amps)
"Vishay cermet are good. One of the biggest con acts has been the
pushing of conductive plastic pots to the audio industry. I don't care
what the brand is - if they make a CP and a cermet (or even a quality
carbon) then my experience is that the cermet KILLS the CP for sonic
quality. The VISHAY cerment (made by their french wing Sfernice))
sounds. like two good fixed resistors, the identical looking CP sounds
like ****! Allen

Oh dear someone else who thinks resistors have a sound.

A pot, whether cermet, conductive plastic, carbon or whatever is a pure
resistance (discounting irrelevant tiny amounts of capacitance and
inductance- wirewound pots excepted) and consequently are linear to the
limits of measurement. Therefore how any pot can be better than another
for sonic qualities is beyond me. Pots vary in the accuracy of their law,
the noise made when being altered, tracking on stereo, how long they last
before track wear is evident etc. Sonic differences are just not there.


Interesting that you are never challenged here, Serge. You wouldn't have to
wander far from this group to find a lot people who quite strongly believe
that all components (resistors, caps, pots &c.) can influence the sound from
audio kit. I have no real knowledge and very little experience, so no strong
views - I always say I think it's possible (even likely) different
components will 'sound different', but is it really *hearable*...???

Digital volume control question....
 

"Andy Evans" wrote in message
ups.com...
Try to get past this 'mutual exclusivity' thing

Would be useful - modern valve amps are full of SS parts.



At the end of the day, valves are an option - pretty much like choosing to
put either English or French mustard on ya weener...!!

Both are good (and better than nothing at all) - some people have a strong
preference, some don't....

;-)

Digital volume control question....
 

Keith G wrote:
"Serge Auckland" wrote in message
...
Andy Evans wrote:
As to audio quality, a conductive plastic pot will have zero effect on
audio quality.

Here's another view from Allen Wright (designs amps)
"Vishay cermet are good. One of the biggest con acts has been the
pushing of conductive plastic pots to the audio industry. I don't care
what the brand is - if they make a CP and a cermet (or even a quality
carbon) then my experience is that the cermet KILLS the CP for sonic
quality. The VISHAY cerment (made by their french wing Sfernice))
sounds. like two good fixed resistors, the identical looking CP sounds
like ****! Allen

Oh dear someone else who thinks resistors have a sound.

A pot, whether cermet, conductive plastic, carbon or whatever is a pure
resistance (discounting irrelevant tiny amounts of capacitance and
inductance- wirewound pots excepted) and consequently are linear to the
limits of measurement. Therefore how any pot can be better than another
for sonic qualities is beyond me. Pots vary in the accuracy of their law,
the noise made when being altered, tracking on stereo, how long they last
before track wear is evident etc. Sonic differences are just not there.


Interesting that you are never challenged here, Serge. You wouldn't have to
wander far from this group to find a lot people who quite strongly believe
that all components (resistors, caps, pots &c.) can influence the sound from
audio kit. I have no real knowledge and very little experience, so no strong
views - I always say I think it's possible (even likely) different
components will 'sound different', but is it really *hearable*...???



I think the nub of your response is that people "believe" things sound
different. It's the same mental process that have people believing in
God, the Tooth Fairy and Santa Claus. They don't have a shred of
objective evidence that things sound different, just their faith.

I'll accept that pots, capacitors, resistors etc. sound different when I
see objective measurements that indicate that there should be a
difference and the results of properly conducted double-blind tests that
show that there was a difference.

S.
S.

Digital volume control question....
 

Serge Auckland wrote:

I think the nub of your response is that people "believe" things sound
different. It's the same mental process that have people believing in
God, the Tooth Fairy and Santa Claus. They don't have a shred of
objective evidence that things sound different, just their faith.

I'll accept that pots, capacitors, resistors etc. sound different when I
see objective measurements that indicate that there should be a
difference and the results of properly conducted double-blind tests that
show that there was a difference.

So is it not the case that metal film resistors have lower noise than carbon ones,
and that this gives an audible and measurable difference in phono and microphone
preamps?

Note that this is a question, not a statement. I haven't measured anything recently.

--
Eiron

No good deed ever goes unpunished.

Digital volume control question....
 

"Serge Auckland" wrote in message
...
Keith G wrote:


Interesting that you are never challenged here, Serge. You wouldn't have
to wander far from this group to find a lot people who quite strongly
believe that all components (resistors, caps, pots &c.) can influence the
sound from audio kit. I have no real knowledge and very little
experience, so no strong views - I always say I think it's possible (even
likely) different components will 'sound different', but is it really
*hearable*...???



I think the nub of your response is that people "believe" things sound
different. It's the same mental process that have people believing in God,
the Tooth Fairy and Santa Claus. They don't have a shred of objective
evidence that things sound different, just their faith.


Let's say they *perceive* things to sound different.

If that is the case and they aren't being fleeced (or even if they are and
can afford it) I reckon there's no real harm in it - people need summat to
believe in and 'audiophile capacitors' are as good as anything else, IMO!!

There's a tradition of Snake Oil squealing in this group and I always think
there's a danger of an equal and opposite fundamentalism creeping in. My own
view is that until I've heard an *obvious* difference - carts (always),
valves (in some cases, not all) for example, I leave the jury *out*....


I'll accept that pots, capacitors, resistors etc. sound different when I
see objective measurements that indicate that there should be a difference

???

Aha!!

:-)

and the results of properly conducted double-blind tests that
show that there was a difference.


That's the problem. I'm not aware of anyone who has tweaked a bit of kit
that hasn't done it without making 'retrospective' comparisons. I bought two
'copies' of the Dynavox EL34 amp with a view to substituting as many
'audiophile' components in one of them as possible while leaving the other
one 'budget Chinese' stock for the express purpose of setting up a permanent
comparison for anyone who wanted to hear it, but I must say I lost
enthusiasm for the idea!! (Maybe some time in the future?)

My dilemma today is this: I want some more speaker bits which I can get
either from Impact Audio (used 'em before - nice people, super service) or
BMM Electronics in Jairmany (never dealt with them) - the trouble is, the
price difference for the same list is none too trivial:

http://www.apah69.dsl.pipex.com/show/Speaker%20Bits.xls

What to do? Fork out over the odds to 'shop local' and keep a UK supplier in
business (clover?) or just say 'sod it' and go for the savings....??? I'm
assuming no great differences in postal charges, but don't want to split the
order (the biggest difference is on the B200s) and incure two of them!

(Usual bloody story innit - the Brits get get shafted all the sodding
time!!)

Digital volume control question....
 

"Nick Gorham" wrote in message

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.

A very similar thing happens with analog level controls. In the real world,
even more so.

Digital volume control question....
 

Serge Auckland wrote:

I think the nub of your response is that people "believe" things sound
different. It's the same mental process that have people believing in
God, the Tooth Fairy and Santa Claus. They don't have a shred of
objective evidence that things sound different, just their faith.

I'll accept that pots, capacitors, resistors etc. sound different when I
see objective measurements that indicate that there should be a
difference and the results of properly conducted double-blind tests that
show that there was a difference.

S.
S.

http://members.aol.com/sbench102/caps.html

--
Nick

Digital volume control question....
 

Arny Krueger wrote:
"Nick Gorham" wrote in message


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.


A very similar thing happens with analog level controls. In the real world,
even more so.



Yes, I guess so by definition, but I would hope a quality pot or stepped
attenuator should start with more than 96db worth of resolution.

--
Nick

Digital volume control question....
 

Nick Gorham wrote:
Serge Auckland wrote:

I think the nub of your response is that people "believe" things sound
different. It's the same mental process that have people believing in
God, the Tooth Fairy and Santa Claus. They don't have a shred of
objective evidence that things sound different, just their faith.

I'll accept that pots, capacitors, resistors etc. sound different when I
see objective measurements that indicate that there should be a
difference and the results of properly conducted double-blind tests
that show that there was a difference.

S.
S.

http://members.aol.com/sbench102/caps.html

Interesting. I'll study it in the next day or two.

S.

Digital volume control question....
 

On Tue, 23 May 2006 11:04:47 +0100, Serge Auckland
wrote:

Andy Evans wrote:
As to audio quality, a conductive plastic pot will have zero effect on
audio quality.

Here's another view from Allen Wright (designs amps)
"Vishay cermet are good. One of the biggest con acts has been the
pushing of conductive plastic pots to the audio industry. I don't care
what the brand is - if they make a CP and a cermet (or even a quality
carbon) then my experience is that the cermet KILLS the CP for sonic
quality. The VISHAY cerment (made by their french wing Sfernice))
sounds. like two good fixed resistors, the identical looking CP sounds
like ****! Allen

Oh dear someone else who thinks resistors have a sound.

That's not someone else, it's only Andy............ :-)

A pot, whether cermet, conductive plastic, carbon or whatever is a pure
resistance (discounting irrelevant tiny amounts of capacitance and
inductance- wirewound pots excepted) and consequently are linear to the
limits of measurement. Therefore how any pot can be better than another
for sonic qualities is beyond me. Pots vary in the accuracy of their
law, the noise made when being altered, tracking on stereo, how long
they last before track wear is evident etc. Sonic differences are just
not there.

Agreed. Having built Vishay-based L-pads, full switched attenuators
with Vishays and Holco metal-films with Elma and Farnell 'military'
switches, and used all kinds of pots, including Alps 'Black Beauty'
and yer actual Penny & Giles studio faders, I concur that there's no
audible difference. Stick with switched attenuators for accurate
tracking at all levels, or a decently built pot like the Alps for
'infinite' level adjustment.
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Digital volume control question....
 

On Tue, 23 May 2006 12:06:42 +0100, "Keith G"
wrote:


"Serge Auckland" wrote in message
...
Andy Evans wrote:
As to audio quality, a conductive plastic pot will have zero effect on
audio quality.

Here's another view from Allen Wright (designs amps)
"Vishay cermet are good. One of the biggest con acts has been the
pushing of conductive plastic pots to the audio industry. I don't care
what the brand is - if they make a CP and a cermet (or even a quality
carbon) then my experience is that the cermet KILLS the CP for sonic
quality. The VISHAY cerment (made by their french wing Sfernice))
sounds. like two good fixed resistors, the identical looking CP sounds
like ****! Allen

Oh dear someone else who thinks resistors have a sound.

A pot, whether cermet, conductive plastic, carbon or whatever is a pure
resistance (discounting irrelevant tiny amounts of capacitance and
inductance- wirewound pots excepted) and consequently are linear to the
limits of measurement. Therefore how any pot can be better than another
for sonic qualities is beyond me. Pots vary in the accuracy of their law,
the noise made when being altered, tracking on stereo, how long they last
before track wear is evident etc. Sonic differences are just not there.


Interesting that you are never challenged here, Serge. You wouldn't have to
wander far from this group to find a lot people who quite strongly believe
that all components (resistors, caps, pots &c.) can influence the sound from
audio kit.

Indeed so, but that doesn't mean they know in any way shape or form,
what they're talking about! :-) Vide the notorious Andy Evans...

I have no real knowledge and very little experience, so no strong
views - I always say I think it's possible (even likely) different
components will 'sound different', but is it really *hearable*...???

If it's hearable, then they sound different. IME, they don't. Yes, I
have a £250 pot in my passive controller, but I won't be buying
another one, nor would I recommend it to anyone else! It does *feel*
very smooth in operation, however. :-)
--

Stewart Pinkerton | Music is Art - Audio is Engineering

Digital volume control question....
 

On Tue, 23 May 2006 13:12:56 +0100, Eiron wrote:

Serge Auckland wrote:

I think the nub of your response is that people "believe" things sound
different. It's the same mental process that have people believing in
God, the Tooth Fairy and Santa Claus. They don't have a shred of
objective evidence that things sound different, just their faith.

I'll accept that pots, capacitors, resistors etc. sound different when I
see objective measurements that indicate that there should be a
difference and the results of properly conducted double-blind tests that
show that there was a difference.

So is it not the case that metal film resistors have lower noise than carbon ones,
and that this gives an audible and measurable difference in phono and microphone
preamps?

Note that this is a question, not a statement. I haven't measured anything recently.

Yes, it's true, but if you can hear that difference, then you are
using *way* too high value resistors in your phono preamp! You won't
hear resistor noise in any other part of your equipment.

BTW, it's also quite hard to find cracked carbon resistors these days,
carbon film seems to be about the cheapest available, and it's got
very little difference from metal film in the noise department. Active
device noise almost always dominates, expect with low-output MC carts,
where excess resistance in the first stage is to be avoided.

--

Stewart Pinkerton | Music is Art - Audio is Engineering

Digital volume control question....
 

"Stewart Pinkerton" wrote in message
...
On Tue, 23 May 2006 12:06:42 +0100, "Keith G"
wrote:


"Serge Auckland" wrote in message
...
Andy Evans wrote:
As to audio quality, a conductive plastic pot will have zero effect on
audio quality.

Here's another view from Allen Wright (designs amps)
"Vishay cermet are good. One of the biggest con acts has been the
pushing of conductive plastic pots to the audio industry. I don't care
what the brand is - if they make a CP and a cermet (or even a quality
carbon) then my experience is that the cermet KILLS the CP for sonic
quality. The VISHAY cerment (made by their french wing Sfernice))
sounds. like two good fixed resistors, the identical looking CP sounds
like ****! Allen

Oh dear someone else who thinks resistors have a sound.

A pot, whether cermet, conductive plastic, carbon or whatever is a pure
resistance (discounting irrelevant tiny amounts of capacitance and
inductance- wirewound pots excepted) and consequently are linear to the
limits of measurement. Therefore how any pot can be better than another
for sonic qualities is beyond me. Pots vary in the accuracy of their
law,
the noise made when being altered, tracking on stereo, how long they
last
before track wear is evident etc. Sonic differences are just not there.


Interesting that you are never challenged here, Serge. You wouldn't have
to
wander far from this group to find a lot people who quite strongly believe
that all components (resistors, caps, pots &c.) can influence the sound
from
audio kit.

Indeed so, but that doesn't mean they know in any way shape or form,
what they're talking about! :-) Vide the notorious Andy Evans...

I have no real knowledge and very little experience, so no strong
views - I always say I think it's possible (even likely) different
components will 'sound different', but is it really *hearable*...???

If it's hearable, then they sound different. IME, they don't. Yes, I
have a £250 pot in my passive controller, but I won't be buying
another one, nor would I recommend it to anyone else! It does *feel*
very smooth in operation, however. :-)


As the only thing between your expensive/irreplaceable speaker drivers
(IIRC) and the full whack from your amp, it's worth every penny if it gives
a lifetime's service and doesn't let go like the cheap one did on my Cheepie
Chinkie amp (on one channel)!! Luckily that was only an inexpensive/easily
replaceable Fostex driver and a low powered amp so no harm done, but you
don't get a whole lot of warning when the music kicks in *flat out*!! :-)

Digital volume control question....
 

Oh dear someone else who thinks resistors have a sound.

That's not someone else, it's only Andy............ :-)

If all the engineers on this group who insist on measurable accuracy in
everything used the same diligence in reading words - maybe not
strictly the domain of whizzing electrons - then it would have been
obvious that this quote came not from me but from Allen Wright, a
respected amp designer and technical author.

Digital volume control question....
 

In article , Nick Gorham
wrote:
Serge Auckland wrote:

I'll accept that pots, capacitors, resistors etc. sound different when
I see objective measurements that indicate that there should be a
difference and the results of properly conducted double-blind tests
that show that there was a difference.


http://members.aol.com/sbench102/caps.html

I've only had a quick look at the above, and the pages linked to it.
However they don't seem to me to be particularly relevant to the question
of capacitors normally having a 'sound' in normal use.

The first thing that struck me about the page was the following which I
quote:

"The signal level was held constant at about 70 volts RMS at 600 Hz across
the capacitors. (for about 26mA signal current). This is probably more
than you would normally expect,..."

My reaction to the last phrase was,,, "indeed!" :-)

I can't recall ever building or using an audio amplifier or tuner that had
anything like this large an *audio voltage* across any of the *capacitors*.
Note the above is 70v RMS *between the capacitor terminals*. i.e. not just
an input where most of the voltage appears elsewhere. I have certainly
built (and use!) amps which have audio voltages this large inside them, but
not between the terminals of any of the signal capacitors.

Given the above, the plots are hardly surprising. Indeed, they seem to me
to agree with work by Doug Self, who simply concluded that we should
avoid significant ac across any of the capacitors in the signal
paths if we used caps like electrolytics. In general, this is quite easy in
my experience.

FWIW The results also seem to agree with measurements I've seen published
elsewhere, and with those which one my honours project students obtained
some years ago in similar tests.

Also, the nonlinearities shown would produce easily measureable levels of
THD. However if you measure many amps that have capacitors in the signal
paths they deliver far lower levels of nonlinearity even when the caps are
outwith any feedback loops. The reason simply being that the ac voltages
on the caps are orders of magnitude smaller than 70v RMS.

I can have a more careful read of the page(s) if anyone thinks it
worthwhile, but I can also comment on another quote:

"The "current monitor" resistor used for all curves was 100 ohms. The
"integrator" was passive, using a 100k and 0.047, 0.1, or 0.47 uF
capacitors depending on the frequency and level. The "X" input to the
scope was fed with an additional series capacitor and adjusted for exactly
"90 degrees" phase shift (typically ran 0.01u into the 10 meg scope probe
resistance) to reduce systemic errors. The generator is absolutely
isolated, being the secondary of a transformer capable of 300 volts into
1k from 15Hz to 1kHz. The bias voltage was added "in series" with
this from an HP regulated and isolated supply. The junction of the current
monitor resistor and the capacitor under test serves as the scope and
system "reference" point."

For a measurement engineer/scientist the above would prompt many questions.
It is not at all clear if any of the results arise due to imperfections in
the system described as we are not given the details of any other tests
used to calibrate or assure the performance of the measurement system. If
caps have such effects, it seems a shame to have so many in the measurement
system without having any info on what effects *they* may be producing...

However can anyone say what domestic amps actually employ ac audio signals
across the signal caps that are this large in nomal use at frequencies like
600Hz? If not, I am not sure why the results show anything about what may
be 'audible' in real amplifiers, 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....
 

Jim Lesurf wrote:
In article , Nick Gorham
wrote:
Serge Auckland wrote:

I'll accept that pots, capacitors, resistors etc. sound different when
I see objective measurements that indicate that there should be a
difference and the results of properly conducted double-blind tests
that show that there was a difference.


http://members.aol.com/sbench102/caps.html

I've only had a quick look at the above, and the pages linked to it.
However they don't seem to me to be particularly relevant to the question
of capacitors normally having a 'sound' in normal use.

The first thing that struck me about the page was the following which I
quote:

"The signal level was held constant at about 70 volts RMS at 600 Hz across
the capacitors. (for about 26mA signal current). This is probably more
than you would normally expect,..."

My reaction to the last phrase was,,, "indeed!" :-)

I can't recall ever building or using an audio amplifier or tuner that had
anything like this large an *audio voltage* across any of the *capacitors*.
Note the above is 70v RMS *between the capacitor terminals*. i.e. not just
an input where most of the voltage appears elsewhere. I have certainly
built (and use!) amps which have audio voltages this large inside them, but
not between the terminals of any of the signal capacitors.

Given the above, the plots are hardly surprising. Indeed, they seem to me
to agree with work by Doug Self, who simply concluded that we should
avoid significant ac across any of the capacitors in the signal
paths if we used caps like electrolytics. In general, this is quite easy in
my experience.

FWIW The results also seem to agree with measurements I've seen published
elsewhere, and with those which one my honours project students obtained
some years ago in similar tests.

Also, the nonlinearities shown would produce easily measureable levels of
THD. However if you measure many amps that have capacitors in the signal
paths they deliver far lower levels of nonlinearity even when the caps are
outwith any feedback loops. The reason simply being that the ac voltages
on the caps are orders of magnitude smaller than 70v RMS.

I can have a more careful read of the page(s) if anyone thinks it
worthwhile, but I can also comment on another quote:

"The "current monitor" resistor used for all curves was 100 ohms. The
"integrator" was passive, using a 100k and 0.047, 0.1, or 0.47 uF
capacitors depending on the frequency and level. The "X" input to the
scope was fed with an additional series capacitor and adjusted for exactly
"90 degrees" phase shift (typically ran 0.01u into the 10 meg scope probe
resistance) to reduce systemic errors. The generator is absolutely
isolated, being the secondary of a transformer capable of 300 volts into
1k from 15Hz to 1kHz. The bias voltage was added "in series" with
this from an HP regulated and isolated supply. The junction of the current
monitor resistor and the capacitor under test serves as the scope and
system "reference" point."

For a measurement engineer/scientist the above would prompt many questions.
It is not at all clear if any of the results arise due to imperfections in
the system described as we are not given the details of any other tests
used to calibrate or assure the performance of the measurement system. If
caps have such effects, it seems a shame to have so many in the measurement
system without having any info on what effects *they* may be producing...

However can anyone say what domestic amps actually employ ac audio signals
across the signal caps that are this large in nomal use at frequencies like
600Hz? If not, I am not sure why the results show anything about what may
be 'audible' in real amplifiers, etc.

Slainte,

Jim

Jim, you took the words right out of my keyboard.

I have never measured any increase in THD with a capacitor in circuit in
the amplifiers I have designed. This is true of all sorts of cap,
electrolytic, tantalum, polyester, polystyrene. Polar capacitors need to
be well polarised or they do perform badly, but otherwise, no change in
distortion was ever measured to the limits of my measuring instruments.
I have not been concious of capacitors adding noise, so conclude that
any changes in performance caused by capacitors must be so far below
other sources of noise and distortion that they can safely be ignored as
having a sonic signature that is perceivable. That's not to say that
one can use any old capacitor anywhere, given that leakage currents are
greater with some caps, internal inductance can be high with some types
and, for example, for decoupling high-speed ICs, physically small low
inductance types need to be fitted close to the IC pins, so that often
determines the type to be used.

S.