Bass and Synth Mixer with FX Loop questions

[CamH132]

I'm looking at building a simple little mixer so that I can plug both my bass and synth into my pedalboard (two inputs, one output). I also want to add in an FX Loop so that I can switch an external pedal in and out of the signal chain before the final output of the mixer.

Based on the schematics I've attached, is this as simple as using 2 channels from the return half of the JFET Splitter/Mixer (scrapping the whole input / send section) and then adding the 3PDT footswitch to the end of it after C8?

[antonis]

Omit Send 3 circuitry and connect 3PDT switch Output to Return 3 mixing circuitry..

[CamH132]

Omit Send 3 circuitry and connect 3PDT switch Output to Return 3 mixing circuitry..

I'm confused. I'm not planning on using any of the input / sends half of the circuit.

I want the bass and synth inputs to be mixed into one signal in the pedal which then goes through the FX send which can be switched in and out of the circuit.

Like this:

[antonis]

I'm confused.

I'm confused, too..!!

I also want to add in an FX Loop so that I can switch an external pedal in and out of the signal chain before the final output of the mixer.

[CamH132]

I'm confused.

I'm confused, too..!!

I also want to add in an FX Loop so that I can switch an external pedal in and out of the signal chain before the final output of the mixer.

ahh i apologise, my wording was a bit weird. i meant the final output of the pedal (between C8 and the output on the original schematic)

with that being said, do you see any issues with the latest schematic i posted, or is it not as simple as it looks?

[antonis]

It should also need mixing resistors between C8 & Input and pedal & FX send..

[CamH132]

It should also need mixing resistors between C8 & Input and pedal & FX send..

Do you mind expanding on this a little bit more just so I can better understand what's going on? What is the purpose of the mixing resistors, what values would you use and where exactly would you put them? (e.g. does the first one just go in series between C8 and the input lug of the footswitch and the second one go between the FX Send of the footswitch and the FX Send output jack?)

and while we're here - is this the best / most efficient way to go about a circuit like this as a whole?
I want to keep this as simple as possible, but also want to avoid any signal loss / degradation.

[CamH132]

I was also wondering if there would be any benefits of adding any buffers in or after the FX send? (the fx send is likely to have a long cable run so i'm concerned about the strength of the signal and the likelihood of any noise issues)

Forgive my ignorance, but I've also been looking around at other simple mixer schematics and am curious if something like what is shown in circuit 3 below is a better way to go about the mixer?

[garcho]

^ yes, that's a good route.

summing amplifier

That's the way to go. Basically, the way analog mixing of audio signals is done most often.

[CamH132]

ok so for the first half of the circuit I now have this (with the addition of a mixing resistor in series between the FX Send lug of the 3PDT switch and the FX Send output jack as suggest by antonis??):




I would also like to add a final master volume control after the FX send. Is this as simple as adding in a pot between the output lug of the 3PDT switch and the output jack or is more circuitry required?

Additionally, there are likely to be long cable runs within the FX Send - should i be adding any input / output buffers here to make sure the signal stays as clean as possible?