12AX7 + LM3886 schematic

[dirkwright]

Hahaha... thats it 😀 No info on the LM3886s feedback loop though. But I found this:

An externally hosted image should be here but it was not working when we last tested it.

Theres 0.2ohm 2w resistors on my output as well

Regards /Bo

That can't be it because there's only 2 of the LM3886's on your board. Is your board stereo? If so, then this is not the schematic for what you've got.

 

[dirkwright]

That PCB-board looks spot on. Any further info on it? The transistors says: S9014, C331


Regards /Bo

The SS9014 is a low noise, low level preamp NPN transistor. It would be funny if it was used as some kind of emitter follower between the tube and the chip.

The load resistor for the tube is way too low. If it were me, I'd power it up, measure the voltage drop across it, figure the current, and then replace the resistor with a constant current diode. But, I think this circuit has other problems.