And, so, - Poindexter - Tube DIY Asylum

And, so,

Posted by Poindexter (M) on August 9, 2006 at 11:14:27

In Reply to: point taken, but... it's just a bias supply! (nt) posted by mhardy6647 on August 9, 2006 at 07:26:04:

What does the business end of this supply connect to, hm?

Even in PP output stages, I have found that the diode RRS is high enough in frequency to become at least partly uncorrelated, and so appear on the output a little.

I've been using Diodes Inc. UF1007 (1KV, 1A) for every sand supply in all my stuff for years. They still have a RR burst, but it's very short and very high frequency, so bypassing with a .01µF ceramic or film/foil cap shunts it right out of there. I use the big-voltage ones because if I get a hundred from Digi-Key, they're 29¢ each.

Doc. B. likes the very similar InterRect UF4007, I'm sure it works fine. Mouser has them, who I haven't used because Digi-Key has so much other stuff I like.

Michael Percy has several kinds of FREDs, which are a little more expensive, but you don't have to bypass at all, since they have essentially zero RRS.

For your bias supply, you could also use Schottky Barrier diodes, the ones up to 100V have become very common and economical. I haven't looked into them, so I don't have a rec vendor. They also have zero diode noise, and are very fast.

Don't shortchange your supplies, they're important. To get up and running, like the gent below sez, bolt that bridge down and go. Get some good diodes and replace it when you can; I bet you'll hear a little blacker background.

Aloha,

Poinz

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Follow Ups Full Thread

Topic - dum-bass question of the day: modern silicon bridge rectifiers - mhardy6647 09:50:23 08/08/06 (14)

Re: dum-bass question of the day: modern silicon bridge rectifiers - Dyna Saur 03:49:26 08/10/06 (0)

I can't believe all of this run around! - morinix 09:48:32 08/09/06 (0)

A tangential observation. - Poindexter 22:41:31 08/08/06 (9)

which individual diodes you recommed ? - lovetube 07:35:07 08/09/06 (0)

point taken, but... it's just a bias supply! (nt) - mhardy6647 07:26:04 08/09/06 (7)

And, so, - Poindexter 11:14:27 08/09/06 (4)

It is only the bias supply...Pluz Mark. - Russ57 14:45:53 08/09/06 (3)

umm, those great engineers used selenium rectifiers (nt) - mhardy6647 16:50:03 08/09/06 (2)

...they wouldn't use them today.(nt) - pedroskova 08:12:48 08/10/06 (1)

I hope not :-) - mhardy6647 09:07:50 08/10/06 (0)

Why a 25a bridge for a bias supply? - Gusser 10:43:43 08/09/06 (1)

it's just a picture! :-) - mhardy6647 16:48:00 08/09/06 (0)

Re: dum-bass question of the day: modern silicon bridge rectifiers - Gusser 11:06:06 08/08/06 (1)

yah, better safe than sorry! Thanks (nt) - mhardy6647 12:33:16 08/08/06 (0)

Follow Ups

And, so, - Poindexter 11:14:27 08/09/06 (4)

It is only the bias supply...Pluz Mark. - Russ57 14:45:53 08/09/06 (3)

umm, those great engineers used selenium rectifiers (nt) - mhardy6647 16:50:03 08/09/06 (2)

...they wouldn't use them today.(nt) - pedroskova 08:12:48 08/10/06 (1)

I hope not :-) - mhardy6647 09:07:50 08/10/06 (0)

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