"Joerg" wrote in message
et...
Lord Garth wrote:

"Joerg" wrote in message
...

Jim Thompson wrote:


Oh my! Nostalgia!

Stumbled onto this site...

http://tdsl.duncanamps.com/schematics2.php?make=Dynaco

I built the FM3 and the PAS2 when I was a kid ;-)


I built more mean stuff when I was a kid. An amplifier with several big
horizontal flyback tubes in there etc. 900V on the plates, directly
cascaded out of 230V grounded mains, sans transformer because that would
have cost too much...

Actually I still got that amp but a typical 120V circuit is too wimpy
for it.


How could you build such an amp and not connect it to your available
230 volt 30 amp mains? It has to use less power than an electric oven!


That's because this amp has what we used to call a "white knuckle
supply". Three cascade stages to get to about 930 volts without a
transformer. Here in the US this doesn't work because the 240V we have
for ovens, A/C or dryers is just the two phases. Each side is 120V to
ground so you'd need a large iso transformer.


So you have 230 volts phase to phase? 3 phase 120 volt yields 208 phase to
phase.
Was your home supplied with 3 phase power?