Send/Receive wiring

[rankot]

This is the question, but also could be useful to someone - I was thinking about how to connect two jacks to have send and receive on my amp. So this is the solution - I thought of using jacks with inside switches:

So, if no jacks are plugged, the signal goes from preamp to the PRE_OUT top tip and its switch, through the ring tip switch to the ring tip, then to switch of the AMP_IN top tip and then to amp.

If I plug PRE_OUT (send) jack, it will disconnect switches, but it will also ground input to the amp through ring tip, which will touch jack ground (I wanted amp to be silent in that case, since I have no master volume after pre).

If I plug AMP_IN (receive), it will break direct connection to the preamp and simply connect to the receive jack. So it will act as a receive. Of course, this input shall be mono, but I don't have a symbol for that.

If no jack is inserted into PRE_OUT, just into AMP_IN, then amp will use only the signal from there.

Did I miss something or not? I don't have this kind of jacks at hand right now, so I can't test it, but just to check if I got it right.

[composition4]

I'm not sure I follow... Are you just trying to wire a normal effects loop that bypasses when nothing is plugged in, or something else?

If so then you don't need stereo switched jacks, you only need a mono normal jack for send and a switched tip mono jack for return. Wire them into the circuit as if you weren't bypassing it, then also wire the send jack's tip to the return jack's switch.

I'm on my phone so can't draw it up, but something like the below (g = sleeve, t = tip, s = switch)



If I've misunderstood what you're doing or trying to do then disregard!

Jonathan

Edit: appears I've misunderstood what you're trying to do... You want the above arrangement except one of your requirements is that the return tip is grounded if something is plugged into the send but not the return?

[anotherjim]

It seems to me that auto grounding the power amp input can't be done with those "normalling" jack switches - they can only disconnect. The ones you can switch everything and anything in any direction are those used by such as Marshall/Fender and others in more recent PCB based amps.
Here's one...
JS-5075 Jalco 6.4mm 90deg PCB Jack Socket Mono C/O
https://www.actionhardware.co.uk/parts-online/index.php?route=product/product&path=34_90&product_id=604
Note that the switch operation is insulated (see the pdf), so it doesn't matter what the audio contacts are used for.

But I think many designers just have a low enough input impedance of the power amp that it doesn't pick up noise too much and they get away without a grounding contact.

Another option is to arrange a microswitch that operates when the plug tip pushes it.

[rankot]

I'm not sure I follow... Are you just trying to wire a normal effects loop that bypasses when nothing is plugged in, or something else?

If so then you don't need stereo switched jacks, you only need a mono normal jack for send and a switched tip mono jack for return. Wire them into the circuit as if you weren't bypassing it, then also wire the send jack's tip to the return jack's switch.

I'm on my phone so can't draw it up, but something like the below (g = sleeve, t = tip, s = switch)



If I've misunderstood what you're doing or trying to do then disregard!

Jonathan

Edit: appears I've misunderstood what you're trying to do... You want the above arrangement except one of your requirements is that the return tip is grounded if something is plugged into the send but not the return?

I want:

• When no jacks plugged, simply connect preamp to amp.
• When only PRE_OUT (send) jack is plugged, ground amp input, so it's silent.
• When only AMP_IN (receive) in jack is plugged, don't connect internal preamp to the amp, just the input jack.
• When both jacks are plugged, preamp is routed to send, and receive to amp.

[rankot]

I have just got two jacks with switches from my friend and wired like shown on the first image. It works just as expected, so if anyone needs similar thing, I can declare this CERTIFIED!

[anotherjim]

Ok, I see it now. Clever.