Late 60's 50W Marshall Bridge Rectifier Specs

[pgussler]

Does anyone have the specs for the bridge rectifier found on a late 60's Marshall 50W Lead.  Part number is IIR GB256/PA 70 21.  Thanks in advance.

[pgussler]

Never mind - found it.   1000v 25A

[PRR]

25A seems mighty generous, especially for late 1960s.

I absolutely approve of greatly over-speccing rectifiers. I used to get paid salary to replace marginal rects but that job is gone. Meanwhile the costs (labor and headache) of replacing will cover a heap of over-speccing so you never have to replace it.

Just be sure it can be made to fit.

[pgussler]

Agree on the amperage generosity and also on the overbuilt approach.  The failed unit is a big sucker to begin with and the dimensional specs from the data sheet for the replacement part indicates it will plop down right in its place.  Thanks for the reply.

[pdf64]

1kV is marginal.
Perhaps that’s why the original failed?
Bear in mind only 2 of the 4 diodes in the FWB package are in circuit.
My take is that even just 2 series pairs of 1N4007 would be better.

[pgussler]

Thanks for the follow up.  All points well taken.

[pdf64]

Here’s report of 1kV diodes failing https://ampgarage.com/forum/viewtopic.php?f=9&t=35385