How hard can this be..?

[NyteOwl]

I tried searching for this info, but apparently the forum's Search Function isn't working...

 

I need a simple A/B switcher/looper that will take a stereo input and either pass it through unaltered (A) or, when I activate the loop, send the original stereo signal out to a stereo delay, send the delay's stereo outputs back to the switcher/looper and then output the blended signal (B).

 

This device will sit on a shelf in my rack and I plan to control it remotely via a Ground Control Pro & GCX, so instead of a having a footswitch to activate/deactivate the loop, all I'd need is a single TS jack to hook it up to a GCX loop configured as a latching switch. Since it will be mounted in my rack, no LED indicators are necessary.

 

I'd also want to keep the size of this box to a minimum so I am wondering if I can use four TRS jacks for the Input, Output, Send & Return jacks instead of eight TS jacks?

 

I can solder fairly well, but other than that I'm electronically challenged, and would appreciate if someone would be so kind as to post simple schematic? Conversely, if anyone knows of a reasonably priced product out there that will do this, I'd surely appreciate that info , too.

[WRGKMC]

From whjat you described a simple DPDT switch of any kind will work including a toggel. You can use a Low impediance mic cabel for the send and return to the echo unit. Have a stereo jack at the box and (And a stereo plug) at the echo end just wire in two 1/4" jacks for in and out of the echo.

Wiring the switch is a breeze. The X's are the switch connection lugs, the arrows show you signal flow when the switch is in either position. In the down position the signal gets bypassed with the echo disconnected, in the up position the signal gets directed through the stereo jack (Or TRS on a patch bay if needed with the right plug configs).

 

 

stereo jack Tip return> X X > Ring of Jack send signal

 

v ^

 

To Out 1/4 " jack

 

^ v

 

X--------X

[NyteOwl]

^^^^^^^

I appreciate the suggestion, but perhaps you misunderstood or overlooked this part:

 

"This device will sit on a shelf in my rack and I plan to control it remotely via a Ground Control Pro & GCX, so instead of a having a footswitch to activate/deactivate the loop, all I'd need is a single TS jack to hook it up to a GCX loop configured as a latching switch..."

 

Since it will be mounted in my rack, a toggle switch is not going to work, and with all due respect, it's not the best option for a guitarist looking to switch an effects loop in and out on the fly.

 

What I need is something analogous to the GigRig Remote LOOPY-2, only with stereo circuitry as opposed to mono.

[WRGKMC]

Sorry, read your post 3 x and still not sure what you're wanting to do. Maybe it has something to do with the Ground Control Pro & GCX you speak of. First you said a simple ABY then you're talking about controlling it with some other unit. Guess I couldnt tell if you wanted the switch in the rack or on the floor. Is this a rack Echo or floor echo, and where will it be in your chain?

Also didnt notice the stereo config but thats still simple with a 3dpdt footswitch and stereo cables.

[NyteOwl]

Sorry, read your post 3 x and still not sure what you're wanting to do. Maybe it has something to do with the Ground Control Pro & GCX you speak of. First you said a simple ABY then you're talking about controlling it with some other unit. Guess I couldnt tell if you wanted the switch in the rack or on the floor. Is this a rack Echo or floor echo, and where will it be in your chain? Also didnt notice the stereo config but thats still simple with a 3dpdt footswitch and stereo cables.

Okay then, I know it's crude, but maybe this illustration will help...

 

 

Left and right stereo channels going in. In the A position, they pass right through; in the B position they go out to the external delay and return back to the box. It's a rather straight-forward loop, only it's stereo, not mono.

 

It's mounted in the rack, as is the delay, so cable runs are short. Location in the chain is irrelevant.

 

The TS jack is a standard 1/4" mono jack into which a standard 1/4" plug will be inserted. The plug is attached to an external momentary foot switch which will control a latching relay which, in turn, will determine which route (A or B) the signal will follow.

 

Suffice it to say the Ground Control and GCX will provide the foot switching functionality without need to explain further.

 

Big questions are, what kind of latching relay do I need to accomplish this, and how do I connect the 9-Volt DC power supply?

[WRGKMC]

Now I got you. First question for me would be, Does the Echo unit have a bypass footswitch jack. Most rack units have one and uitlize a relay inside the unit. Using it may allow you to intergrate it into the Ground controll you were speaking of. Most rackmount footswitch options are a simple spst switch or momentary switch option.

 

If it doesnt have one, a relay option would be a good next step as you outlined. I wouldnt do the routing inside the patchbay for a few reasons. 1, Theres no reason to, 2. you would need to rewire the plug configuration inside the patchbay and mount the relay in there where there is zero room in moct patchbays I've opened. 3. the relay can introduce noise beacuse its a coil in close proxcimity to unshielded hot wires throughout the interior of the patchbay chasis.

 

I would mount the parts in a small metal box or even a half rack chassis if you can find one. I would go to mouser and look for a 4dpdt relay. I would also 8 x 1/4" for complete signal isolation.

 

I jotted down a the connections in a PDF file attatched.

 

As far as the power supply/wallwart, The ratings of the relay will need to be known first. Youll need a higher current rating on the supply and load resistors to prevent a dead short. A coil is just a long piece of wire without a lot of resistance so to prevent a dead short to the supply you need something to take the load besides the coil. I would also add diodes and or caps to prevent popping when the relay engauges. I use an old Weatstone Bridgebox to figure out what resistance will work best with minimal load to the supply. You may find a simular diagram on the net or someone can suggest a definate safe circuit. There may also be a dual SSR that will work as well most will do the job with 5vdc and you dont have the load or time delay etc to get the job done.

[NyteOwl]

Whew!!!

 

Relays, diodes, caps, etc. Apparently, this is a much more complicated DIY project than I anticipated, something I just proved to myself by looking at all the components inside a Whirlwind A/B Selector.

 

I think I'll pass on building this myself and look for a store bought solution.

[WRGKMC]

Yea, unless you got time to tinker and buy the parts, you're better off just buying somethings sometimes. It one thing if you're a pack rat and have junk parts to scrounge through to build stuff, but in reality you dont save anything building from scratch when you consider the time and material to build. Unless its something that is totally unique where you cant buy or its something you just like doodeling with as a hobby I say why bother. I have cabinets full of parts i've collected over the years. If I have a choice of buying vs building, I usually buy. I dont mind repairs so much, but having to earn a living doing repairs kind of takes the noverty out of it like I had as a kid experimenting.