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-   -   Best diodes for generic power supply (http://www.diyaudio.com/forums/power-supplies/75428-best-diodes-generic-power-supply.html)

rtarbell 8th March 2006 02:07 AM

Best diodes for generic power supply
 
I've seen several posts about the best audio quality diodes to use, but I get a little bit of contradiction between didoe types:

Schottky diodes seem to be more audio quality than standard, but do we want to use fast recovery or soft recovery?

==> Similar note, has anyone tried Fairchild's stealth diodes?

BWRX 8th March 2006 02:14 AM

Try both and see if you can tell a difference. You won't need fast recovery for dealing with 60Hz line frequencies. Diodes used in a switching supply are a different story...

Tweeker 8th March 2006 02:20 AM

Its not the speed of fast diodes that matters at 60hz, its thier better recovery giving less HF noise when they are shutting off.

pwillard 8th March 2006 02:39 AM

I wish I could convince myself that fast recovery is an issue at 60 hertz...

This is one of those things I guess I'm just going to have to try myself and compare.

vectorplane 9th March 2006 06:01 AM

This diode story is one of those placebo effects in audio.

You can use chicken fence wire to connect speakers to an amp. Then tell a guy it's gold plated solid silver $300 mega-monster interconnects, and he'll swear he can hear profound presence, soubtle overtones, rich full-bodied sound that envelops you like the flavor of fine cognanc...blah, blah, blah, ... you know the drill...

Then tell him it's chicken wire, and he can suddenly hear the rough, jagged, scratchy granularity caused by the myriad diodes formed by the cheap iron molecules in the cable...

There's never been any evidence, measured objectively with instruments, to suggest that any power supply rectifier diodes used in place of the 1N400x will provide any significant improvement in sound parameters.

The drive to substitute more expensive alternatives for all components in a power amp stems from a desire to improve the design without an actual knowledge of how to improve the design.

It demonstrates complete unawareness of a fundamental principle of electronic design:
The topology must factor out component characteristics,
so that overall quality of result depends on circuit arrangement, not on individual component properties and tolerances.

The sound of an amplifier should not depend on the quality of components, but on the arrangement of those components. With few exceptions, this design goal is to a large extent achieved in most designs today.

So you're trying to improve something which has already been rendered irrelevant by the design.

This in turn causes an individual to convince themselves they can "hear" an improvement, in order to achieve self-justification. Communicating with others who have done the same modification provides reassurance through cross-confirmation. So now you have a club of believers. Something like this:

http://www.alaska.net/~clund/e_djubl...rthsociety.htm

lndm 9th March 2006 08:34 AM

A spike (as can be seen across the diodes when they turn off), is energy with a uniform frequency distribution. That is it may set off resonances throughout the power supply if they exist.

Fairly easily fixed though, put some snubbers across the diodes, and place small resistances between stages in the ps.

I believe Nelson Pass has a few good things to say on his web site on this subject too. I seem to recall him recommending which diodes to use.

richie00boy 9th March 2006 09:08 AM

Schottky diodes have the smoothest recovery of them all, but they are not as robust nor available in as high PIV rating as other types.

My own opinion is that with massive cap banks etc the conduction angle of the diodes becomes smaller so any recovery time will become more important. I use Schottky's, I like to over engineer.

Nordic 9th March 2006 09:34 AM

I recently started using UF5408 diodes, they are good for 1000V 3A, and are wicked fast for the price, they are also quite large, wich I like.

richie00boy 9th March 2006 10:15 AM

They may be fast, but their recovery - which is the most important parameter on 50/60Hz mains - is poor. I would not use these diodes.

Upupa Epops 9th March 2006 10:22 AM

Sound of diodes....Jesuschrist !.... :eek:


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