Yes, again: mains-powered KILLER amp without a power transformer.

[engels]

And again I was thinking about all that electricity in the AC socket... so please tell me what may be wrong with the following idea:

Let's say, I've got a separate preamp with its own PT and line out.
The power amp has an input 1:1 isolation transformer.

Then I'm rectifying the mains (we've got 230 here) getting about 320V of B+. To save the filament transformer I'd use something like 50C6 tubes (50V@0.15A filament, 200V plates, 2.6K load, 6W output - is SE mode). Or maybe a more "conventional" 50L6 which is 3.8W into 4K in SE.

Let's say, I've got four 50C6 ($3.70 at Antique Electronics) or 50L6 ($7.40 at Antique Electronics) tubes in PP plus a phase inverter which is a bit hard to find but I guess it should be something like two 14A4 loktal triodes (12-14V@0.15A) or maybe two 14C7 ($1.95) pentodes wided as triodes (Couldn't find any 25V@15mA triode).
With all the filaments in series I get about 225-228V@0.15A

The OT is a bit of a question.... I'd love to make an OTL output (to compliment the PTL supply). The load for these 50V tubes is a bit odd.

So how may someone get killed with this type of amp? Or what bugs should someone expect?

 

[SY]

DEADLY DANGEROUS. Don't even THINK about doing this.

 

[ray_moth]

I agree with SY, it's dangerous and not worth the risk. If you don't want to use a tranny for the heaters, stick to SS.