power supply and speco specs for s.e.x. 2.0?

[Jim R.]

I have a s.e.x. 2.0 which is in a state of disassembly right now and pretty much ready to do something interesting with it and I was wondering what the specs of the power supply are and if the specos can be configured for other impedances.  The idea would be to leave the power supply pretty much alone but see what other tubes I may be able to use (even if it will require a separate VA tube in front.  Thinking along the lines of an el84, 6bm8, 6v6 and 6f6.

Thanks,

Jim

[Paul Joppa]

The Speco is 8K on the 0.625-watt tap. You can actually calculate this, since you know the voltage (it's a "70-volt distribution" transformer - power equals volts squared over impedance, so impedance is volts squared over power.

On the 1.25 watt tap, the impedance is 4K; this is what we used for the Paramour.

The power supply is capable of 1.8 amps total at 6.3 volts, and 70mA total at 366 volts. You have already measured that voltage, at the input of the plate choke, during the checkout phase.

[Jim R.]

Paul,

You're right, I did measure that voltage, but it was a long time ago and that still doesn't tell me what the total current capability is -- now I know ;-)

As for the Speco, thanks for he guidance -- I've never worked with 70 volt distribution transformers, but now I can calculate the impedances for the other taps, which I do have a list of somewhere.

Looking like there should be enough capacity here for a stereo SE 6bm8 amp -- a really sweet sounding tube, IMO..  Maybe also a SE 12b4a headphone amp.

Once my other stuff is done, I really want to get back to truly mucking about and experimenting.

-- Jim

[Paul Joppa]

SEX was the first Bottlehead product, before the Bottlehead name even. Stood for Single Ended eXperimenter's amp. It's nice to see the habit persists!