A new noise then rectifier valve gone

bacchanalian

I have a Victoria Regal that I run with a 5Y3 rectifier and 1 6V6. I have it set around 3/4 maximum volume and treble and bass at nearly maximum yang.
Recently it developed a new noise. The best way I can think of describing it is that it is similar to the noise switching the power on would make but quieter. Last night there was a louder crackling pop and the rectifier valve had gone. 
I thought Aha! that new noise must have been the rectifier on the way out. But no, changed the rectifier valve, 5UGB this time and the noise is still there.

Thank you in advance for any advice

ICBM

Probably an arcing power valve or a failing filter cap. Either of those could cause premature rectifier failure.

It could also be a poor contact in the standby switch. I suspect this may be yet another amp with the switch in the wrong place in the circuit - upstream of the first filter cap - I can't find a schematic but there is a pic on the Victoria website in which that appears to be the case. If so, using the standby switch will stress the rectifier and won't have helped.

bacchanalian

Many thanks @ICBM.
I have a few other valves I can swap in 

bacchanalian

I have swapped all of the valves including the pre-amp valves and am still getting the random quiet crack/pop noise.
It does sound like something shorting.

Does that mean a capacitor service is in order?

ICBM

bacchanalian said:

I have swapped all of the valves including the pre-amp valves and am still getting the random quiet crack/pop noise.
It does sound like something shorting.

Does that mean a capacitor service is in order?

Possibly, or it could be a resistor on the way out and just a coincidence (or standby-switch related) that the rectifier died at the same time.

bacchanalian

Thanks @ICBM, you are a gentleman

I will see how things go over the holidays