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Old 14th February 2014, 06:09 PM   #11
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Quote:
Originally Posted by frank1 View Post
Some time ago, I built a test amp with relay switchable capacitors so I could change the value from the listening position after reading a load of rubbish here.

The small values just gave and apparent loss of bass with no other noticeable affects.
I wouldn't personally bother with many small capacitors in parallel as I was measuring about 0.01Ohm ESR @ 200kHz from my 10,000uF caps.
Frank
Smaller capacitors discharge faster, though.
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Old 15th February 2014, 03:57 PM   #12
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Before jumping to conclusions please read the following posts:

The (high-cap.) unregulated PSU for chipamps

http://www.diyaudio.com/forums/chip-amps/49813-my-first-try-lm3886-layout-any-comments-suggestions-16.html#post581230

http://www.diyaudio.com/forums/digital-source/48990-blackgate-caps-out-production-so-4.html#post574431
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Old 15th February 2014, 04:40 PM   #13
00940 is offline 00940  Belgium
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Peter Daniel's amps are certainly works of amazing craft. When it comes to the power supply's caps, all he's offering is a subjective opinion which cannot be explained.

Interestingly, the discrete amps' crowd never took interest in those undersized PS.

Gootee has a very nice excel sheet to get an idea of required capacitance btw: Chip amp on the way
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Old 15th February 2014, 04:57 PM   #14
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Originally Posted by 00940 View Post
Peter Daniel's amps are certainly works of amazing craft. When it comes to the power supply's caps, all he's offering is a subjective opinion which cannot be explained.
Well, I think that most of the HIFI community is based on subjective opinions .
My father is specialist in reproduction of pictures and he says that it will never be possible to reproduce the colour of a flower.

The same is happening here.

I build my first amp according to P. Daniel's instructions and according to me it sounds very well.

I'm using quiet easy to drive speakers and that maybe is the reason I'm very pleased with it.

Anyway, the subjective experience of quality keeps the HIFI discussions interesting as this is impossible to reject.

Last edited by Joerytech; 15th February 2014 at 05:01 PM.
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Old 17th February 2014, 11:53 AM   #15
AndrewT is offline AndrewT  Scotland
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Quote:
Originally Posted by Joerytech View Post
Before jumping to conclusions please read the following posts:

The (high-cap.) unregulated PSU for chipamps

http://www.diyaudio.com/forums/chip-amps/49813-my-first-try-lm3886-layout-any-comments-suggestions-16.html#post581230

http://www.diyaudio.com/forums/digital-source/48990-blackgate-caps-out-production-so-4.html#post574431
Carlos probably did hear a change when he inserted the snubber on the OUTPUT of the PSU.

But that does not make the snubber right.

If the fast switching of the transformer was causing an audible problem, then a snubber at the transformer was the right place for it.

If the local decoupling in the amplifier was lacking, then a snubber at the amplifier would be the correct place for it.

Carlos' design is proving that unsnubbered was possibly wrong, but in the dozen or so years since then, many have come to realise what the snubber is and what it does and why it should be located in the position that allows it to do it's job.
Separating the snubber from the "problem" with long lengths of connecting cable is not the right way.
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Old 17th February 2014, 01:03 PM   #16
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Originally Posted by Destroyer OS. View Post
Smaller capacitors discharge faster, though.
Which means that the amp can be worked on more quickly after power-off. Woo!
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Old 17th February 2014, 01:56 PM   #17
godfrey is offline godfrey  South Africa
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Originally Posted by Joerytech View Post
It seems not everybody agrees with you
What do you expect, people around here will argue about anything.

Seriously though, if you look a little closer you'll find that the strongest protagonists of undersized power supply caps also promote ideas like:
a) Bronze heatsinks "sound better" than aluminium ones.
b) Good bass requires lots of current. So if you want your chipamp to have good bass response, you need to make the input impedance as low as possible to force it to draw as much current as possible.

IIRC, the rot started some years ago when a reviewer questioned the undersized caps used in an overpriced, under-engineered commercial amp. Needless to say the manufacturer denied that cost cutting had anything to do with it, but then went on to invent some nonsense about "signal storage" to justify their claim that supply capacitors should be as small as possible. Unfortunately that mantra's been repeated over and over ever since by people who don't actually know anything about electronics.

You have to remember that some people who don't know any better actually believe the utter bilge routinely published in magazines like 6Moons. After absorbing enough of that nonsense some of them consider themselves to be experts, and set about sharing their "wisdom" with anyone who cares to listen. Unfortunately a lot of innocent noobs get infected that way, and then go on to spread the nonsense further.
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Old 17th February 2014, 02:30 PM   #18
Turbon is offline Turbon  Sweden
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I haven't tested it godfrey but a bronze one should give a more stable temperature. If a fast variable temperature does something to the SQ it might be worth taking in consideration. So "a" might hold.

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Old 17th February 2014, 03:58 PM   #19
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I remember a test that was published where they asked 10 best trombone players of the world to play on two different trombones, one made of steel and one made of copper.
At first all the trombone players sworn that a copper trombone sounds superior to the steel one.
They let them play with and without blind fold on both of them.
Without blindfold they almost all thought the coper one sounded better, with blindfold it was fifty fifty.

This was an easy test to rule out the subjective opinion because it only had 2 parameters.

To my opinion in the case of using high or low capacitance with CG this test is equally easy to do and I can not imagine that this is not already done before.
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Old 17th February 2014, 07:02 PM   #20
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Originally Posted by 454Casull View Post
Which means that the amp can be worked on more quickly after power-off. Woo!
You don't see the value in quicker response to changes in demand for power? K... These aren't constant current supplies.
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