Loop box question

[DaveTV]

I was thinking about making a loop box for my effects, and I'd like to make it as versatile as possible.

I was thinking it might be useful if the "send" in each loop could also double as an additional output, like using an A/B switcher. If I used it this way, then I would leave the "return" jack empty. In order to do this properly, I expect I'd need to ground the "return" in each loop, correct? Would this be possible if I were to use a closed tip jack (like Switchcraft 112A) for the "return" so that the tip is grounded when nothing is plugged in?

[Andreas]

I'm not sure if I understood correctly what you want, so let me first describe how I understood your question (and if that's already wrong, forget the rest  :wink:):

You want to make a box which let's you switch on and off the effects in the loop passively by using a footswitch. However, if there is nothing plugged into the return, you want the internal link (usually: effect off) be on all the time and use the send as an output as well as the usual output of the loop box.

Now, let's assume that the above is really what you want:

First of all, you can't (or rather shouldn't) do this passively. You need to at least buffer your send in this case, better the send and the standard output. Otherwise it would be no better than a Y-cable and this would be really horrible whenever at least one of the outputs goes into a not-very-high-impedance input.

Second, you'll need one of those jacks which have an additional contact which is normally connected to the tip contact, but when the plug is inserted, the tip contact is pushed a bit outwards and so the connection to the additional (let's call it bypass) contact is opened. Now you can connect the input signal directly to this bypass contact (and the output to the tip contact as usual), so that when no plug is inserted, the input is directly connected to the output, whereas this connection is opened when a plug is inserted.

Now that I've written all this and re-read your message, I realize that I indeed got you wrong. Second try:

You want only one of the outputs be active at a time (like an A/B box as you said and I somewhat missed). If this is the case, things get much easier. You can do that passive and just like you described. Use that closed tip jack (exactly what I described above I guess) and ground the bypass connector. I suppose you alreade switch the send as well as the return with a DPDT switch, so you don't have to change anything else as far as I can see. The only problem may be that the input as well as both outputs share one ground and it may cause a ground loop, but this problem already existed before the modification.

[DaveTV]

Indeed, the second scenario is what I'm aiming for. Thanks for the input!