Amps - Whats in em and why?

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Daniel Quinn
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Re: Amps - Whats in em and why?

Unread post by Daniel Quinn » Wed Nov 06, 2019 2:10 pm

Polys arent used in power supplies for good reason.

valvesRus
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Re: Amps - Whats in em and why?

Unread post by valvesRus » Wed Nov 06, 2019 2:34 pm

Daniel Quinn wrote:
Wed Nov 06, 2019 2:10 pm
Polys arent used in power supplies for good reason.
Polypropylene capacitors ARE used in power supplies, for good reason. :)

Commercial designs may eschew them (due to size constraints) but DIY users find them superior.

If I built a DIY version of an NVA amp it would be substantially bigger due to the Poly PSU caps I would use.

Daniel Quinn
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Re: Amps - Whats in em and why?

Unread post by Daniel Quinn » Wed Nov 06, 2019 2:50 pm

Show me a supplier of poly 10,000uf 63 v

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Hemmo1969
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Re: Amps - Whats in em and why?

Unread post by Hemmo1969 » Wed Nov 06, 2019 2:55 pm

Ali Tait wrote:
Wed Nov 06, 2019 1:34 pm
Polypropylene caps are superior to electrolytics in the signal path of an amp as far as SQ is concerned.This would be true for power supplies also, but polys would be huge in size in the values generally used, which is why ‘lytics are used. Polys will also last far longer than lytics.
Cheers for that

valvesRus
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Re: Amps - Whats in em and why?

Unread post by valvesRus » Wed Nov 06, 2019 3:38 pm

Daniel Quinn wrote:
Wed Nov 06, 2019 2:50 pm
Show me a supplier of poly 10,000uf 63 v
If you wanted that value then you'd have to use multiples of a smaller value.

I have some here for my 833a amp rebuild, they are 130uf @ 1900v @ 40A and measure 3.5" diameter and 5" long. For valve amps one does not necessarily need large values of capacitance, especially at 1250v HT.

Daniel Quinn
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Re: Amps - Whats in em and why?

Unread post by Daniel Quinn » Wed Nov 06, 2019 4:00 pm

Hence they are no good for solid state amps

valvesRus
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Re: Amps - Whats in em and why?

Unread post by valvesRus » Wed Nov 06, 2019 4:04 pm

Daniel Quinn wrote:
Wed Nov 06, 2019 4:00 pm
Hence they are no good for solid state amps
Impractical -- Yes

Expensive --- Yes

No good ---- unlikely.

You can bypass electrolytics with a small value film cap which might be worth trying.

Daniel Quinn
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Re: Amps - Whats in em and why?

Unread post by Daniel Quinn » Wed Nov 06, 2019 4:26 pm

You forgot the fact there would be so many.

valvesRus
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Re: Amps - Whats in em and why?

Unread post by valvesRus » Wed Nov 06, 2019 4:32 pm

Daniel Quinn wrote:
Wed Nov 06, 2019 4:26 pm
You forgot the fact there would be so many.
That was covered by "impractical". :)

Lurcher300b
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Re: Amps - Whats in em and why?

Unread post by Lurcher300b » Wed Nov 06, 2019 5:02 pm

what amps have "output transformers" apart from valve based ones ?
Macintosh made a solid state amp with a output transformer at one time, may still do.

But the entire diversion could have been avoided by admitting and correcting the typo ASAP.
Last edited by Lurcher300b on Wed Nov 06, 2019 5:10 pm, edited 1 time in total.

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