Help needed with 12 au7 stereo amp tube

[continental55]

  Hi the socket on my amp its the 12au7 that has the metal shield around it 

I tried tio carefully solder in a new socket but now the tube doesnt light up. I tested the tube and its good


any tips appreciated would this cause no sound at all?  the box is a regis   even a clear diagram of the connections would be great

[jukenorman]

If it's not lit, that would point to a problem with the heaters / wiring. The heaters are supplied directly from the power supply (two yellow wires from pins 1 and 6 of the amp. socket). Pin 1 yellow is looped to tube (valve) base connections 4 & 5 on the 12AX7 and 12AU7s and base connection 5 on the 6CY7s and 6973s. Pin 6 yellow is looped to tube base connection 9 on the 12AX7 and 12AU7s and base connection 4 on the 6CY7s and 6973s. Assuming that you have the US amplifier model 35260-A as originally fitted.

Norman.

[continental55]

thank you

there is one heavier wire that is bridged to pin 3 and 4 and looks like the centre wire from the input plug from tonearm went to pin p9 
but that may be wrong.  one more question are there any pins left not connected ?
sorry for all the questions and thanks a lot

[jukenorman]

No, you're getting your numbers mixed up - 4 and 5 are bridged. All pins are used, three for each triode and three for the heaters. I hope you can read the (half) schematic below. One of the stereo inputs goes to pin 7, the heaters common is pin 9 - see the heater circuit at the bottom of the schematic.