Can you explain what is going on? Seems weird. I tried disconnecting the feedback circuit but that really didn't change anything. Why would my output PP voltage be 3.2V while my first stage output voltage at the 2C22s is 5.1V pp?
Plate Voltages are 104.9 and 102.8 for the #76s
Plate Voltages are 112.7 and 110 for the 2C22s
Cathode Voltages are 4.1 and 4.1 for the #76s
Cathode Voltages are 3.8 and 3.9 for the 2C22s
Cant really measure the grid voltages.
Waveform is still flattened at the outputs (Positive deflection...
OK, I resoldered the feedback resistors in. With the higher B+ the waveforms look better bit still flattened off quite a bit over 2.8V PP.
Interestingly, the waveform looks much better after the first stage than after the second. Could the feedback circuit be causing this?
Blue trace is after...
I had those same tubes as well as a pair of the EML meshies. The Sophias looked spectacular but only lasted for a short time as did their replacements. The 2.5V filaments are vey dim even within the mesh plates.
I think all that noise came from incorrectly loading if the preamp. Does that make sense?
I haven't tried the different VR tubes yet. Was attempting to understand what was in front of me with the lower B+.
I'll try that tomorrow.