Re: Re: Following 2 Power Tube Amp Design

[beelzebum]

above an below the “plate resistor”. its the 100k resistor above the plate. reading above it will show the B+ and reading below it will show whats actually on the plate. its usually easier to take a reading from there than to read your plate voltage from the socket.
with the 68k resistor reading different when its in circuit, that is because the 1.5k is grounded on one side, also the 68k goes to your output transformer that is also grounded on the other side through the speaker jack. so in circuit using an ohm meter it will show a different resistance because you are also reading other resistances in parallel.
as for the heater voltage if it is center tapped or referenced to ground with a hum balance pot, then you will see about 3.15v from either side to ground. if you read from one side of the pilot light to the other you should see 6.3v.
and for your input problem, like i said before if you are using that picture of the input jack that was posted as a guide. it is wrong. you will have problems.