Valve Itch phono

[Salas]

If having 190-200V at cathode (50K node to ground measure point) then 122V keeps under 100V heater to cathode max allowed, so its good.

 

[merlin el mago]

Elevated cathode to gnd 212VDC
R11 right channel 36mA
R11 left channel 35.7mA
R3 right channel 1.06mA
R3 left channel 1.06mA

 

[Salas]

By "elevated cathode" you mean top triode's cathode, right? Still at 90V heater to cathode if so. What value resistors you use in the heater elevation divider? Maybe you could divide B+ to 150V heater elevation so to have better distance.

 

[merlin el mago]

Yes. I use two 470K resistor. How can do to have B+ 150V heater elevation?

 

[Salas]

Must be load related, the values should still be the same between them for 1/2. Do you have 2 470K to parallel each one existing or 2 220K in their place? Should boost the now 122V reading I would expect.

 

[Salas]

Elevated cathode to gnd 212VDC
R11 right channel 36mA
R11 left channel 35.7mA
R3 right channel 1.06mA
R3 left channel 1.06mA

Link me the schematic the designations refer to.

 

[merlin el mago]

Both 470K

 

[merlin el mago]

Measurement heater elevation

 

[merlin el mago]

Sorry my mistake 3.6mA instead 36mA😱

V3 1.06V
V4 3.6mA

 

[Salas]

Your input tubes bias 1mA others bias bit higher, so 210V at V3 cathode instead of 190V is normal. Your 6SN7 biases like other 6SN7s I have measured at 3.6mA.

 

[Salas]

What is the elevation of V3 heater to ground in the end 122V or 212V? You keep on changing it.

 

[merlin el mago]

Sorry Salas, I check again, I have to solder the resistors.

 

[merlin el mago]

What is the elevation of V3 heater to ground in the end 122V or 212V? You keep on changing it.

Pin 3 150.4V
Pin 8 158.2V

 

[merlin el mago]

Heater elevation V4

Pin 3 211.1V
Pin 6 210.8V

 

[merlin el mago]

Are OK?

 

[Salas]

Pin 3 150.4V
Pin 8 158.2V

Tell me heater pins 4,5 to ground for 6N2PEV.

 

[Salas]

Heater elevation V4

Pin 3 211.1V
Pin 6 210.8V

Those are the cathodes. Tell me 7,8 heater pins to ground.

 

[merlin el mago]

Voltages acros valves

V1 6N2PEV
triode pin 1-3 70.8V
triode pin 6-8 62.8V

V3 6N2PEV
triode pin 1-3 100.9V
triode pin 6-8 93.4V

V2 6SN7
triode pin 2-3 89.3V
triode pin 5-6 88.5V

V4 6SN7
triode pin 2-3 88.8V
triode pin 5-6 88.9V

 

[merlin el mago]

Tell me heater pins 4,5 to ground for 6N2PEV.

Those are the cathodes. Tell me 7,8 heater pins to ground.

Do you want that I measure each heater wire to ground for V3 & V4? or simply heater voltages of both valves?

 

[Salas]

Just measure voltage across lower resistor in the voltage divider, it will be the same for all heaters.