How to upcycle a 210-0-210v power transformer

[fyzygy]

I've inherited yet another 60s tape recorder power transformer. It's got 2 x 6.3v @1.5A heater windings, and 1 x 210-0-210v HT secondary @0.1A. Assuming the use of a SS rectifier, is there any kind of push-pull guitar amp I could build around this HT secondary, and expect halfway decent results? Most of the amp circuits I've seen call for a 260-0-260v HT secondary, minimum. But maybe I could swing a 6AQ5 or 6BM8 PP design? Any suggestions would be appreciated.

[nickholme1]

Hi, I have a JCM800 style amp that I have just finished which uses ECL86 valves with an HT of 290v. These valves have an ECC83 style triode and an EL84 style pentode. There are a few posts on here dealing with these valves. Apparently you can use any EL84 circuit/schematic pretty much as is. Some posts suggest a Power Valve cathode resistor of 330 Ohm. I'm using 135 Ohm at this HT and the amp is awesome. The anode current is 36mA so you have a little spare capacity at 100mA. Heaters are 700mA so 1.4A for 2 using the 2 x triodes as a LTPI plus 1 or 2 preamp valves.
Should make a pretty decent 14-16 watt amp.

[fyzygy]

SWIM suggested I look at Orange Tiny Terror -- 7/15 watts switch taps off the HT secondary at either (roughly) 250 or 180 volts AC. I don't know if that switches any component/values at the same time -- or just drops B+ to obtain the lower power output. Anyone can confirm? In which case, it seems, the main effect of a lower B+ is simply ... reduced power output?

[Daviedawg]

The Tiny Terror has a single pole switch between taps, with the ac going straight to the rectifier. Nothing other than two ac voltages.

I never use the 7 watt option which suggests that it is not as useable as the full power. But it is quite a while since I tried it.

Dd