Blowing fuses on startup?

It's hopefully just the fuses - but there is a small chance that you've done some other damage, possibly to a filter cap, with the increased voltage from the SS rectifier.

I have a nasty suspicion that it might be something like that, since the wrong mains fuse type will usually blow on power-up, not when taking the amp off standby. A blown fuse on switching the standby to on usually indicates a fault in the HT circuit - or tubes, but you've eliminated those...

Hope I'm wrong - maybe worth another call to Jeff, he'll be able to tell you whether this is even a possibility from the component ratings in the amp.

 

If you re-installed your rectifier tube (assuming the tube isn't bad) and it still blows, chances your amp will need repair. I have a Germino and the fuses kept blowing on me too when taking the amp off standby as John mentioned. I went to Radio Shack and kept replacing the fuses. Come to find out it, my rectifier tube was going bad. Replaced it and no problems since. As long as the fuses are the same amperage as required, I wouldn't lay too much blame on them, but start troubleshooting elsewhere.

 

That does sound like the wrong type of fuses.

The standby terminology can be confusing... "standby on" means the amp fully operational, not the "amp on standby", to me. Now I've re-read your first post, it's obvious...

The best type of fuses for amps are the T type with the coiled 'spring' inside - they have the highest short-term-surge rating compared to their actual blow value.

I really wish more amp makers would fit proper separate fusing for power and HT circuits though - some, like Marshall, have always done so - it makes problem tracing like this far easier than just relying on a single mains fuse, and protects the amp better too. That way you can use a slightly less over-sensitive mains fuse value, since it's there to cover only for major shorts in the PT or filament circuit.