Ultimate Rectifier Board - is this really an Ultra rectifier board ???

[kagliostro]

Hi friends

I find the advertising of an "Ultimate Rectifier Board" as a commercial product

as you can see it is a full wave rectifier with 3 diodes in series in each branch

in parallel with each diode there are one cap (.01uf - 1Kv) and one resistor (470k)

I'm a bit confused about the presence of the resistors

I can understand the presence of the cap

but the presence of the resistor in my mind give the way to the AC to go on the B+ rail

isn't it ??

and also is a "must to do trick" ??

I have never seen that before

Kagliostro

[FYL]

// caps act as roughy snubbers and can cut HF noise, // resistors balance currents betwen the diodes.

Such a topology is widely used in indus power supplies. Is it worth the bother with modern UF diodes and guitar amps? I don't think so but YMMV as usual.

[PRR]

Back in 1966 we did throw resistors across series-diodes to equalize the reverse voltage. Otherwise the leaky ones would take less voltage, the least-leaky one would get most of the voltage, and fail.

Modern diodes have higher breakdown voltage, very much lower leakage, and break-down gently. It's not necessary to add "equalizing" resistors on series diodes for any reasonable B+.

Those inexpensive ceramic caps look like an added failure point.

[The_Gaz]

Adding snubbers without doing the math can make noise worse in my experience. Here's the classic article on snubbers (that I don't understand):

http://www.hagtech.com/pdf/snubber.pdf

{EDIT: URL clean-up --PRR}

[Tiny_Daddy]

If you want 2 diodes in series just get a small 1000V bridge rectifier and snip off the AC leads.

[HotBluePlates]

This does look like a "me too!" product.

If the builder knew what they were doing, they would know that you don't need 3 series diodes anymore, even though the old amps had 3 series diodes per leg. Unless they're using something smaller than a 1N4007, of course... But I doubt they can buy a smaller diode any more cheaply than that one.

[kagliostro]

MANY THANKS TO ALL

what you say have sense

-----

if I snip the AC leads in a bridge

I obtain a single diode with double reverse voltage ability

and also a doubled current ability - right ?

Kagliostro

[FYL]

Here's the classic article on snubbers (that I don't understand):

http://www.hagtech.com/pdf/snubber.pdf

[Tiny_Daddy]

If you snip the AC leads you do not get double current because one series-ed pair will always hog most of the current.