I'm using the 7199 tubes in the amp section to deal with the inherant Miller effect in the 12ax7 . The other threads are dealing with hum problems which I have since mostly solved. I still have some hum now so I may end up abandon the 7199 set up.
But the unbalance problem now is not in the amp section because I made a jumper rig with alligator clips so to clip into any point in the whole amplifier from the headphone jack of my phone. So at the input of the volume pot I can play my phone and I get balanced sound from my speakers.But if I jumber into pin 7 of V3 & V 4 I get unbalanced sound. So the problem is in the second half of V4. But it has a new socket, new resistors, put other tubes there as well changing out the coupling capacitors twice.I've ohmed out the pins of the tube from from one side to the other, I balled the socked to see if there's any solder shorting it out. Unsoldered the input wire to rule out the tone PC. Jumpered the ground of the cathode resistor, checked the value of the cathode and anode resistors. I thought maybe its the heater circuit since V4 is the second tube in the heater string but my voltages at both V3 & V4 anodes are the same.
I'll put up a diagram of the circuit I'm using to support the 7199 tube
There are some differences between whats on diagram and whats on the amp. The bias resistors are not 220k but are330k, coupling capacitors are not .1uf but are .047uf , I'm using IBAM also. The feed back is open loop too.