• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Help with tube wiring


2010-11-03 6:14 am

I'm building the Angela single ended 6v6 amp which is based on the 5F2 circuit and i've seen 2 different ways to wire the 6v6 & 12ax7 tubes.

One way is: 1x green 6.3v lead connect to ground and the other to pilot light then to lug 7 of 6v6 and lugs 4 & 5 of 12ax7. Pins 1 & 2 of 6v6 are grounded and pin 9 of 12AX7 is also grounded.

The other way is both green 6.3v leads connect to pilot light then 1 lead connects to pin 1 & 2 of 6v6 then pin 4 & 5 of 12AX7. The 2nd 6.3v lead connects to pin 7 of 6v6 then pin 9 of 12AX7. There is no mention of grounding the tubes.

Which way is correct?

The other part of my post relates to connecting the output transformer. I'm using the weber OT which has 5000ohms primary leads of blue and brown with the brown having a phase dot. It has a secondary lead of yellow (8ohms) and black (common) lead. The black has a phase dot in the hookup diagram.

Do I connect the OT as follows:

Brown lead to pin 3 of 6v6,
blue lead to pin 4 (there is a wire connecting from pin 4 to the +ve lead of the 2nd 16mfd cap,
yellow to tip of speaker jack &
black to sleeve/ground of speaker jack?

By the way, I'm using 3x 16mfd caps and a choke. I'm connecting 1 lead of the choke to the +ve lead of the1st filter cap where the lead from pin 8 of the 5Y3 rectifier also connects. The other choke lead is connected to the +ve lead of the 2nd cap and is also where the 22K resistor connects.



2008-08-23 7:28 pm
I think that second way is correct, because pin 1/cathode/ must be connect with cathode resistor and cap, according schematic 5F2. Instead grounding the heating, You will lift heating by 19 v, that is better idea against noise. Pin 8 You can connect to pin 1.
Last edited: