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SSE possible transformer problem.

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and suddenly more b+

Just a curiosity question. I got new cathode bias resistors and soldered them in. I put the 5AR4 back in to check it out to see what values I'm getting now. My B+ went up to 400v from the original from the original 378v when I first tried it with the 5AR4. What might cause this, that just the fact the the amp had time to break in? A poor transformer connection when I first hooked it up, though I don't know were it would have been.

I have a 10 watt 820 ohm resistor in right now because I wanted to parallel it with a 1500 ohm to get 525 ohm's for 6l6 type tubes and 820 ohm's for 6v6 type tubes. My plan was to use the 5U4GB and some zener diodes on the center tap to get a B+ around 315v for the 6v6's.

I'm not complaining about the extra B+, I can work around it for the 6v6's, but I'm just curios why 20 extra volts suddenly appeared. Any ideas?

James,
 
Is this under load? Could just be your mains voltage.

Yes its under load.

I got my little zener B+ dropper built today. I didn't want to use a resistor but, because of the extra 20 volts, I added in a 100ohm 10 watt resistor. I got the B+ down to 308 with the 5U4GB tube, and was able to give a couple of my Motorola 6W6GT tubes a try. The sound with this combo is very warm and quite nice. Listening to some live Grateful Dead, Jerry Garcia's guitar was to die for. This gives a nice range of tubes to play with. I also got another 6N6C coming to replace the bad one. Weather permitting on my days off, its now time to build it a proper home.
 

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Its done, here's the pics.

I got it done yesterday, except for some nomenclature on the back, so I can remember what the switches do.:D Gave it two inputs, selectable on the front for CD and one for vinyl. The switches on the back control CFB, Triode/UL, cathode bias resistor selectable for 525 or 820 ohms, and a switch to kick in the zeners/resistors on the center tap to drop B+ down around 50 volts for 6V6GT's. Thank again to Tubelab and everybody else for their help.
 

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