Marshall Lead 100 Mosfet, Blown Rectifiers/Outputs

[axa]

right.... the meter reads RMS...
so assuming this apparently unidentifiable rectifier is silicon, the result would still be about 54V, (neglecting the ripple voltage and what not)
Phew... so the transformer seems ok, i really didn't want to have to buy a new one...

So back to the original issue, I was going to go with this rectifier, rated max 50Vpp 35Vrms 6A:
BR605 Rectron | Mouser

But knowing what i know now, i think its older brother, rated max 100Vpp 70Vrms 6A would be a safer bet:
BR61 Rectron | Mouser

how about that?

What strikes me is the original filter caps on the amp are rated 50V, and while it would explain a few things... it just seems strange to me that Marshall would cut it so close to the max Vpp.
Again, from what what i understand its a good rule of thumb to rate your caps for voltages between 1/3 to 3/4 of its value...
I for one am going to replace them with least 63V.
Even 25 years ago, i cant believe the extra cost would be that prohibitive would it?
What could i be missing?

[J M Fahey]

What could i be missing?

To begin with, in 25 years USA slowly crept wall voltage up.
The amp was probably designed for 115VAC ; today's wall power may be between 120 and 127VAC.
Also idle voltage is usually higher, as soon as the amp starts putting out some power, tha rails go down by a few volts.
And about a commercial manufacturer using "just necessary" parts rating but not extra?: it's seen everyday.
Plus 25 years ago 50V big capacitors were abbundant, while 63V ones were much less available quite more expensive.
I remember that, I've been making commercial amps for the last 43 years or so.
Today it's not much of an issue.