Noisy Cricket Mkii – Stereo input

[benny_profane]

I was thinking about building up a noisy cricket mkii amp with a switched headphone out option. Since I have some parts of my chain that are stereo out and headphones are obviously stereo, I wanted to have the option of a stereo in. Would I double up the entire circuit—doubling the poles and replacing pots with dual gang—to do this?

I think my main question is whether I need a summing circuit to handle mono. Or, should I use switched jacks and just have one circuit channel run if there's only a mono input? That makes sense for a mono in / mono out, but I'm not entirely sure how to run a mono in / double mono (for the stereo headphone) out with just switched jacks and no physical toggle. Hopefully all of that is clear.

I'm attaching the mono schematic.

[jimilee]

Stereo 1/4" out jack will work in either situation.


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[HamSandwich]

I think your best bet is to design it in stereo, then give it mono capabilities. If you want to keep true stereo, you'll need the circuit you posted twice with a left and right input. You can wire one input with a switching jack so that when there is no plug inserted, the signal coming from the mono input is split to the unused stereo circuit. That should be all the switching you'd need to do, no need for toggles or summing circuits.

[benny_profane]

This is my understanding of the input side of things: two mono inputs with redundant circuits for left and right channels.

Say left channel is the mono input. Do I wire the right input with a switching jack so that the right channel contains the same signal as the left if only a mono signal is provided?

I'm still a little foggy on the output. If the main out (for a speaker) is mono, do I use a stereo jack so that the right channel then goes to ground via the sleeve of a TS cable?

I'd like to have it so that the headphone output would ground the speaker out. Here, do I use a switching stereo jack with an isolated ground between the circuit output and the speaker out? That way, if there is no headphone TRS in the headphone out, the signal passes through the headphone out jack and goes to the speaker out. If headphones are inserted, the signal is routed to the headphones (the ring is isolated from the speaker jack sleeve ground) and there is only output through the headphones?