Power Supply Dropping No Current Draw

[GoghVan]

OK, I haven't seen this one before.

Here's what happens. With all of the tubes out I get high enough voltage from the power supply. Plug in a few tubes, even with the outputs not installed and I get only about 20 volts. The amp works at the low voltage(with 2 12xxx7's and 2 6L5's, as I have it hooked up to a load and scope. It does NOT draw current and the power x'former does not get hot.

I'm using a JJ 40/20/20/20 and I tapped off the main B+ for an adjustable bias. It's a non-traditional Deluxe Reverb circuit without the 2nd input and no tremolo.

As far as I can tell my wiring is OK. Do you think the cap could be opening up when a load is connected or could I have a bad power x'former???

Any thoughts???

PS. I am using a variac. It would probably be easier to find if the amp was drawing current.

Thanks

[GoghVan]

OK.....this was an old project that I made some changes including putting smaller output and power x'formers. It just dawned on me....that was the problem. The power x'former doesn't have a center tap so I'll need to dump the diodes and install a full wave rectifier. LOL...duh...

I guess that's what happens when you go back to messing with a project after a few years.