I'm planning a build for a guitar amplifier with 2 stages, the first being a tube pre-amp and the second stage being a solid state amplifier. Both amplifiers will be powered from the same source, a 31v DC power brick.
The pre-amp will be powered with a DC-DC boost converter from the 31v DC power brick to obtain the high voltage required; the boost converter ground output is tied to the input ground. The audio signal ground will be tied to the same ground.
The solid state amplifier requires a dual supply which I will create with a voltage divider, giving -15.5v, virtual ground and +15.5v.
As the audio signal ground will be relative to the ground of the 31v power brick (equivalent to the -15.5v of the voltage divider) then this signal would cause an issue connecting from the output of the pre-amp to the input of the solid state amp, effectively shorting -15.5v and the virtual ground.
It would seem that I need to isolate the audio signal so it can be provided as a floating AC voltage.
Can the signal and ground be isolated by adding a capacitor in series with each component like so:
Or would the only solution be a 1:1 audio transformer?