XLR & Jack ABY Type Splitter

[muirs]

Hi All,

I have had a bit of a search through and dont seem to be able to find any threads on this so am asking here, apologies if this is a daft query.

I have only just started making pedals, and have only made a basic boost pedal so far, and that was from a kit - I enjoyed the process and am building up my bench.

I am struggling to find a pedal out there that suits my exact needs so think I may be able to build it:

I run an SM58 into a BOSS VE-20 vocal effects (only one input), but have now begun playing cello as well as harmonica so need to switch between a sitting position where I want to have another SM58, and also I am hoping to use a Shure 520 DX "Green Bullet" Harmonica Microphone that has a jack connector,

The closest thing I can find is a Hotshot ABi that can toggle between 2 x XLR inputs, but i need thew additional input for the harmonica mic

I dont want any of the mics to be open when I am using another mic, and it would be perfect if I could switch with my feet as I move between the instruments and main vocals quickly

If anyone knows of something out there that exists already or could help me work out a build I would greatly appreciate it,
Thanks in advance for any helpful comments,
Cheers,
Chris

[PRR]

Multiple microphones suggests a mike mixer. $99 for a Behringer at Banjo World.

Foot-operated mike mixers are very rare.

[AtomicRob]

A small digital mixer with scene or snapshot memory would do the trick. Depending on the mixer some take a foot switch directly which you can use to switch between snapshots (Behringer Flow 8 for example.) Many/most digital mixers also respond to midi so you could use a midi foot controller. But if you just need to change presets that approach seems overly complex.

[muirs]

Hi Guys, thanks for the replies! So can I feed a VE-20 vocal effect unit with one input from a mixer, I assumed that wouldnt work?

That Behringer Flow-8 looks fantastic by the way, thanks for the tip!

[Processaurus]

Hmm, one issue with a simple xlr switcher (diy doable) is that the green bullet has higher output.

Not maybe the solution you were hoping for but for simplicity what about using the hotshot (or other XLR A/B switch) with the two 58's, and program a preset on the vocal processor that sounds like the green bullet? The green bullet is cool, but I shudder when I see one come out when I'm doing sound, feedback city.

[Processaurus]

Otherwise one could possibly make a very elaborate custom ABC switcher. The logic could be CMOS flip flops using the foot switch to pull the set pin high and diodes to the reset pins on the other switches flip flops. Then maybe a preamp for the green bullet and a transformer-less DI circuit to get the green bullet balanced and quiet like the 58's.

[muirs]

Thanks for sharing your knowledge Processaurus! The green bullet is fantastic for the harmonica so my ideal scenario would be your second suggestion - although it is quite far over my head currently so I will need to do some research, any pointers you can give to help with what I need to learn would be greatly appreciated. Only if you have time though, I shall continue googling and working it out myself using your kind input as a jumping off point

[Processaurus]

Thanks for sharing your knowledge Processaurus! The green bullet is fantastic for the harmonica so my ideal scenario would be your second suggestion - although it is quite far over my head currently so I will need to do some research, any pointers you can give to help with what I need to learn would be greatly appreciated. Only if you have time though, I shall continue googling and working it out myself using your kind input as a jumping off point

I wouldn't suggest it as a first project but if the subject of solid state switching and logic gates is on your radar and you have a basic electronics class under your belt, some good reading here at Geofex:

Solid state switching:
http://www.geofex.com/article_folders/cd4053/cd4053.htm

Note, there are alternatives to the 3x SPDT analog switch in the article, you could use the CD4066, which is 4x SPST switches, or the CD4052, which a 2P4T analog switch (like a rotary switch).  RG is right about biasing the signals to go through the analog switches, but it is also possible to use a bipolar supply with the 405x multiplexers (with the negative supply hooked to the Vee pin) and not have to do any biasing and coupling caps.

Check out the logic circuit with the Octal Latch chip in RG's multi-vol- it could be the basis of an ABCDEFGH switch. 
http://www.geofex.com/Article_Folders/multivol/multivol.htm
There is also a 9v friendly alternative to his octal latch chip in the CMOS 4000 series, the CD4042 quad latch:
https://www.ti.com/lit/ds/symlink/cd4042b.pdf?ts=1645819414746&ref_url=https%253A%252F%252Fwww.google.com%252F

For the XLR connections you would just duplicate the switching for the hot and cold wires:
https://www.boxcast.com/blog/balanced-vs.-unbalanced-audio-whats-the-difference

And a transformerless DI circuit for the green bullet:
http://www.paul-gemine.co.uk/diboxes.html

[Processaurus]

Or $99 mixer from banjo world!  Or a couple Mic mute pedals and the discipline to turn one off when you switch to another?

If it didn't have to be foot operated, a table top box with 2P3T rotary switch could do the XLR's in a ABC fashion.  If it popped, there are special "make before break" rotary switches.  That would be a simple project.