Solid state output valve

[ppppenguin]

I still wouldn't bother with a dummy load for the filament. Of course you can measure the LT and HT voltages, both with and without a dummy load. I doubt you'll see much difference. If the mains transformer is run close to its limits then not having a heater load will be a help. In any case the set will run cooler.

The real hazard with high mains is saturating the core of the mains transformer. This is independent of load. The primary current will rise rapidly as you increase mains voltage and the core starts to saturate. you can measure this with a DVM on current range and a variac to adjust the voltage. Take care as you'll have a temporary rig with live mains.

If the mains is high, saturating the core or giving unacceptably high LT and HT, then the answer is a buck transformer. It's just a small mains transformer with a secondary voltage of the amount you want to subtract. The secondary is wired in series with the incoming mains so as to reduce the voltage. You have a 50:50 chance of getting a boost rather than buck first time you try this

I'm using a buck transformer in a small TV monitor to reduce the dissipation in a series regulator transistor: http://golbornevintageradio.co.uk/forum/...p?tid=7789