Bridge Rectifier - what alternative?

[Reeler]

A quicky question for you guys.

I want to buy some Bridge Rectifiers S25VB40 for 1984 amplifiers. (25amp 400v). Can't get exact part number. There are many alternatives at the moment on the market but, according to spec data, they all differ in some way or other.

Any particular specifications I should look out for, to be the same?

There seem to be a lot of robust looking BRs on the market at the moment advertising 25amp 1000v. (metal casing instead of plastic), would these do the job?

If it helps, [take it easy on me I'm a novice], the transformer is 800va....the wiring configuration allows for changing from class A to Class AB by swapping the wiring to the Rectifier around. There are no markings on the transformer. The highest reading I've managed to get from any of the wiring configurations, (using a multimeter) is 105v.

Thankful as always

Reeler

[ostripper]

GBPC5010W-G Comchip Technology Bridge Rectifiers

These are the 50A 1000V units I use on my 250W amps. With heatsinking , they can handle anything... plus they are only $3.75 USD apiece. I know your trafo ,too. It is 52-0-52 Vac .. mine is 53.5-0-53.5Vac/ 1000VA and I get 75-76 V DC.

Changing from class A to AB has nothing to do with the power supply. It is wholly amp topology dependant. you could overbias the BJT output stage to get class A up to 10w or so but that heatpipe cooler might not handle the dissipation !!!

OS

[nigelwright7557]

For my high power amps I use a 200volt 35amp bridge rectifier from Maplin, RS or Farnell.

[Reeler]

Thanks Nigel & OS

Originally Posted by ostripper

Changing from class A to AB has nothing to do with the power supply. It is wholly amp topology dependant. you could overbias the BJT output stage to get class A up to 10w or so but that heatpipe cooler might not handle the dissipation !!!

OS

OS, you are adding to my education all the time, without knowing.

One of my amps flew into a flurry of sparks, bangs & smoke precisely because I changed from Class A to AB (by resoldering the cables) without re-adjusting the bias control down to zero and working upwards. I blew most of the 12 Transistors [2sa1215 & 2sc2921] expensive! ouch! and their corresponding resistors into the bargain. Lord I love the smell of burning plastic in the morning.

Now I know why I should have been concerned in the 2 mins of pipe gurgling.

Am interested in your transformer info.
But I have loads of wires coming from mine! I have one trafo removed completely....maybe another time I'll ask you how I should test it in order to get some replacements.

Reeler