Ordered wrong transformer. Is it worth keeping?

[hesamadman]

I ordered a hammond 290ax ( http://www.hammondmfg.com/pdf/EDB290AX.pdf ) but I meant to order a hammond 269jx (500vct 69mA). I have no idea how this happened. Its for another one of my 5 watt amp thats modeled after the gretsch 6151. Im usng the 1760c OT ( http://www.hammondmfg.com/pdf/EDB1760C.pdf )


This 290ax has a larger secondary. By 150V. My question is, using this transformer, would I have to alter the circuitry pretty significantly? Right now the filter caps in the power supply are rated for 450v but thats with the other transformer (269jx) installed on the breaboard. What other differences would I expect using this. I know a bigger plate voltage on the tubes for one thing.


i think i have too many projects going on at once 

[tubeswell]

So the HT winding is 325-0-325 @ 80mA, and it has a 5V 2A winding and a 6V 2A winding - should be good for a tweed champ or princeton with a 5Y3GT and a 6V6, or a tweed deluxe, or harvard 5F10 or anything similar with a 5Y3GT and 2 x 6V6.

[hesamadman]

So the HT winding is 325-0-325 @ 80mA, and it has a 5V 2A winding and a 6V 2A winding - should be good for a tweed champ or princeton with a 5Y3GT and a 6V6, or a tweed deluxe, or harvard 5F10 or anything similar with a 5Y3GT and 2 x 6V6.

The build that I have on the breadboard now is pretty much that. I uses a solid state rectifier though. Its a single 12ax7 and a 6v6GT. Tone and volume. I think im going to just keep the transformer instead of getting the smaller one. I have the smaller one installed on the breadboard to test the amp. Ill just see what happens. :)


Would you have any input on my filter caps. What volting rating I can get away with. Like I said....right now its installed with all 450v caps.

[shooter]

hopefully this is right  325*1.414 =~460v.  when I get close I series up 350v caps and use 150k balancing resistors.  I didn't look at your schematic but would think you could get by with series cap on the 1st stage, the rest RC taps could probably be the 450s.  hope that helps

[sluckey]

Would you have any input on my filter caps. What volting rating I can get away with. Like I said....right now its installed with all 450v caps.

I would use 500V caps with a 325-0-325 transformer.

[tubeswell]

So the HT winding is 325-0-325 @ 80mA, and it has a 5V 2A winding and a 6V 2A winding - should be good for a tweed champ or princeton with a 5Y3GT and a 6V6, or a tweed deluxe, or harvard 5F10 or anything similar with a 5Y3GT and 2 x 6V6.

The build that I have on the breadboard now is pretty much that. I uses a solid state rectifier though. Its a single 12ax7 and a 6v6GT. Tone and volume. I think im going to just keep the transformer instead of getting the smaller one. I have the smaller one installed on the breadboard to test the amp. Ill just see what happens. :)


Would you have any input on my filter caps. What volting rating I can get away with. Like I said....right now its installed with all 450v caps.

What Steve said 325-0-325 with SS produced a B+ of around 460V - so go with 500V caps, or


If you utilise the 5V winding and chuck a 5Y3GT in, you'll get more like 340-360, which is perfect for a tweed princeton. You can still use the SS diodes (1 wired in series between the HT winding and each rectifier tube plate pin (Pins 4 and 6), with each SS diode's banded-end pointing towards the plate pin) to protect the circuit from a rectifier tube short, and it will drop the same amount of forward voltage as a tube rectifier would. So you would only need your 450V caps in that case.