Tube Driver Debigg (Please Help!)

[kurtlives]

I know you guys probbly always get this but I am sure I have things wired up correctly.

I have built a GGG Tube Driver. Only mod is I added a bias knob. For the life of me I cant get it to work. I had audio but the pots didnt work like they were soposed too or didnt work at all. Now when I test it I get no audio. Bypass works and I am getting 15V to the PCB.



Voltages...With tube in and pedal ON.
1. 5.40V
2. -2.79V
3.-2.69V
4. 0.01V
5. 0V
6. 3.61V
7. -2.77V
8. -2.69V
9. 0V                          Btw the tube does glow and get warm.

IC.
1. 0.03V
2. 0.03V
3. 0.03V
4. -2.67V      Seems too low
5. 0V
6. -2.24V
7. 11.85V
8. 12.52V

Thanks

[dschwartz]

that would be a magic tube cause there's 0 V at the heater pins...

[kurtlives]

Well it does glow....weird....Anyone?

[jjs]

There is 0 V DC across the heaters. They are connected to 12.6 V AC it seems. So this is allright.

The -2.67 V for V- is too low. I would search in the power supply for some error. Maybe measure V- again with the tube and the IC removed (or measure the power supply seperately if possible). Maybe this helps.

[MikeH]

Looks like pins 6 and 1 of the tube should be the same voltage, and they're not.

[kurtlives]

Ok I have isolated the problem...

With the tube in and notthe IC the V+ is 14.5V and the V- is -14.5V.

Now with just the IC in and not the tube the V+ is 14.5 and the V- is -2.67V.

So the problem lies in the op-amp section. Anyone have any ideas?