Supro 1624 amp kit

[Ampzone]

According to the cathode voltages shown (and cathode resistance values), V1a is passing 1.6mA, V1b is .5mA, so shouldn't voltage drop across R7 be larger?

Edit: I missed that V1a cathode is connected to V3a cathode, so the 1.6mA is for both triodes.

So in effect, by removing V3 (tremolo) you would see at 80-100v drop on pin 1 plate (V1)? With V3 12ax7 plugged back in you jump back to appx 200v in V1 on the plate? As it is now it's about 100v on pin 1 V1.

[g1]

Yes. The stock way is biasing for 2 triodes, if you remove the trem tube you will need to increase the cathode R to put the bias back cooler like stock (which will increase the plate voltage).
Looking at V2, I think a value of 3K3 to 4K7 will put you back in the stock bias range for the V1a triode.

[Ampzone]

Yes. The stock way is biasing for 2 triodes, if you remove the trem tube you will need to increase the cathode R to put the bias back cooler like stock (which will increase the plate voltage).
Looking at V2, I think a value of 3K3 to 4K7 will put you back in the stock bias range for the V1a triode.

Ok very cool, so I will raise V2 cathode (pin 3 - 2.2k) to something between 3.3-4.7k. I have a 3.9k I can try.

[Ampzone]

I assume this negative voltage augmentation would apply to removal of any tremolo tube in say a Fender? As often players remove them for more gain.

[g1]

If I understand your question correctly, no.
In this case the trem tube is only affecting the plate voltage of V1 because it is sharing V1's cathode resistor.
In the typical fender amp, both sides of trem tube have their own cathode resistors.
However, the typical Fender has V1 & V2 second halves sharing a cathode. So pulling Ch.1 tube would have effect on Ch.2 and vice versa.

[Ampzone]

If I understand your question correctly, no.
In this case the trem tube is only affecting the plate voltage of V1 because it is sharing V1's cathode resistor.
In the typical fender amp, both sides of trem tube have their own cathode resistors.
However, the typical Fender has V1 & V2 second halves sharing a cathode. So pulling Ch.1 tube would have effect on Ch.2 and vice versa.

Ok I see. I replaced the V1 pin 3 1.5k cathode resistor to at 4.7k.

New Readings-
V1 Pins
1 - 156v
6 - 112v