diytube.com

I picked up this board on eBay from someone's abandoned project. It's mostly set up as a Darling build with a mish-mash of parts, some of them completely wrong. They put in two 1k resistors for the cathodes of the power tubes resulting in just 500 ohms. They likely burned up a nice pair of 1626 tubes this way! Maybe they thought they could make a hybrid board and switch between 6L6's?


So I've ordered replacement parts for this including some output transformers from Musical Power Supplies. I'll have to wait for these, almost as long as waiting for Edcor's. Seems like there are backlogs everywhere for transformers. I already have the tubes, I've been sitting on these for a while now. And I recently picked up an Antek toroidal power transformer with a center tap, AS-05TC200. Since this has two 6.3v windings I'm considering just wiring them in series for the 12.6v heaters. Any thoughts on this? The voltage doubler is already populated on the board.

Now for a mystery.


Between R18, R20 there is a jumper wired in, and I have no idea what this is for. That location is not labeled on the board. Should I leave it or snip it out? Does anyone know?

It finally dawned on me that the board I have was set up to use 12V6 output tubes, that's why the cathode bias resistors are 500 ohms with screen resistors installed. A quick search found this thread about it, http://www.diytube.com/phpBB2/viewtopic.php?f=19&t=4979. Is the original builder watching this forum?

I also suspect that the mysterious jumper lead and connector to an empty virtual tap resistor will provide 12v power. I'll leave these in place and check them when I power it up.


Does anyone want to take credit for this board?

Here are pics of the completed amp. I used an Antek toroidal power transformer mounted in a chrome air filter cover.

Very nice! Glad it's in good hands :)