Hi Folks – I’m rebuilding an old pre-amp and want to add a switch to bypass the gain stage leaving just a buffer with unitary gain when switch is on.
I run multiple dif sources and power amps off it and many of the combinations don’t need the preamp gain – basically it just seems unnecessary in these cases to attenuate the majority of the signal (by turning the vol right down) just so the preamp can them amplify it back up again.
The circuit is attached below. Basically, it is a cathode follower input buffer, cathode-coupled to a non-inverting gain stage with a cathode follower serving as an output buffer.
My initial instinct is to inject the signal (via a switch) to the plate of the second triode to bypass the gain stage and just leave the output buffer.
Will this work? I’m guessing I will need at least a coupling cap to block DC from flowing back to the source?
It has also been suggested to me that i could bypass the feedback resistor to provide 100% feedback and therefore unitary gain – is this a better option?
My circuit knowledge is a bit basic – so be gentle!
I run multiple dif sources and power amps off it and many of the combinations don’t need the preamp gain – basically it just seems unnecessary in these cases to attenuate the majority of the signal (by turning the vol right down) just so the preamp can them amplify it back up again.
The circuit is attached below. Basically, it is a cathode follower input buffer, cathode-coupled to a non-inverting gain stage with a cathode follower serving as an output buffer.
My initial instinct is to inject the signal (via a switch) to the plate of the second triode to bypass the gain stage and just leave the output buffer.
Will this work? I’m guessing I will need at least a coupling cap to block DC from flowing back to the source?
It has also been suggested to me that i could bypass the feedback resistor to provide 100% feedback and therefore unitary gain – is this a better option?
My circuit knowledge is a bit basic – so be gentle!