Amps - Whats in em and why?

All general audio posts go here.
Daniel Quinn
Posts: 8586
Joined: Thu Jul 12, 2012 7:16 am
Has thanked: 24 times
Been thanked: 399 times

Re: Amps - Whats in em and why?

Unread post by Daniel Quinn »

Polys arent used in power supplies for good reason.

valvesRus
Posts: 562
Joined: Sat Feb 24, 2018 2:34 pm
Has thanked: 25 times
Been thanked: 63 times
Great Britain

Re: Amps - Whats in em and why?

Unread post by valvesRus »

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
Posts: 8586
Joined: Thu Jul 12, 2012 7:16 am
Has thanked: 24 times
Been thanked: 399 times

Re: Amps - Whats in em and why?

Unread post by Daniel Quinn »

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

User avatar
Hemmo1969
Posts: 302
Joined: Sun Sep 24, 2017 11:57 am
Location: South Yorkshire
Has thanked: 17 times
Been thanked: 7 times
Ukraine

Re: Amps - Whats in em and why?

Unread post by Hemmo1969 »

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
Posts: 562
Joined: Sat Feb 24, 2018 2:34 pm
Has thanked: 25 times
Been thanked: 63 times
Great Britain

Re: Amps - Whats in em and why?

Unread post by valvesRus »

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
Posts: 8586
Joined: Thu Jul 12, 2012 7:16 am
Has thanked: 24 times
Been thanked: 399 times

Re: Amps - Whats in em and why?

Unread post by Daniel Quinn »

Hence they are no good for solid state amps

valvesRus
Posts: 562
Joined: Sat Feb 24, 2018 2:34 pm
Has thanked: 25 times
Been thanked: 63 times
Great Britain

Re: Amps - Whats in em and why?

Unread post by valvesRus »

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
Posts: 8586
Joined: Thu Jul 12, 2012 7:16 am
Has thanked: 24 times
Been thanked: 399 times

Re: Amps - Whats in em and why?

Unread post by Daniel Quinn »

You forgot the fact there would be so many.

valvesRus
Posts: 562
Joined: Sat Feb 24, 2018 2:34 pm
Has thanked: 25 times
Been thanked: 63 times
Great Britain

Re: Amps - Whats in em and why?

Unread post by valvesRus »

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
Posts: 933
Joined: Tue Jun 14, 2016 1:58 pm
Has thanked: 0
Been thanked: 16 times

Re: Amps - Whats in em and why?

Unread post by Lurcher300b »

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.

Post Reply