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Need schematic for ABY+Looper

Vic Winters

Vic Winters

Apr 20, 2006
4,057
398
Western NY
#1
I want to make an ABY box with a switchable loop in one of the channels. I have a Morley ABY and a home made true bypass looper, but I'd like the convenience of both in a single enclosure.

I want the ability to do the following:

A w/ loop
A w/o loop
A w/ loop + B
A w/o loop + B
B

I have the majority of parts I need, and I'm handy with a soldering gun, so all I need is a schematic. I found a schematic for the Morley, but the Morley has a PCB and I have no idea how to trace that, nor do I really wish to try and recreate it.
 
#3
morley_aby_schematic.gif


Questions I have.

1. What are the V+, V-? Battery leads?
2. What are the boxed A's?
3. Anyway around having to use those jacks? If not, I assume Small Bear would be a source for them?
4. What is the purpose of the 100K ohm resistors?
 
#4
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V+ is positive voltage, V- is negative voltage, but you shouldn't need a dual rail supply to do this (ie; V= and V- in one device.) In fact, if you are prepared to go without LED's you won't need ANY supply voltage whatsoever.

You can use whatever jacks you want to use provided they suit the purpose. Something this simple doesn't require a circuit board - you will be able to wire all this up point-to-point style once the switches and jacks are mounted into the enclosure.

So, if you have made a bypass looper before, this is just an extension of that. My advice would be to copy what you did with your bypass looper, then just Frankenstein in the ABY switches. Ignore the LED's for now just to keep it simple, then once you've got the important bits working, think about adding a battery and some LED's.
 
#7
In nifty's diagram, the only jack requiring a TRS is the B output jack as it is closing the -9V lead. On that one the -9V goes to the ring and when you plug a 1/4" mono in it shorts the ring to the sleeve and -KAPOW!!- completed circuit. (Hopefully not kapow as that would be a poor design, but you get the idea) The box should still work without the battery, but there will be no indication of what is on or off and that will all be guesswork.

All the rest should have the input/output soldered to the tip and the sleeves should all be connected as the ground via the casing (or some other means if your casing isn't conductive). You can use TRS, but you don't need to and it doesn't matter as long as you wire to the correct positions, the rest will take care of itself.

Hope that was clearer than mud.
 
#8
Tip is ALWAYS signal. Sleeve is ALWAYS ground. Ring is only ever needed to 'switch' the power, and it is usually always wired to the negative lead of the battery. When you plug in a mono jack plug, the plug shorts the battery negative to ground and wang, current flows.

But like I said, I suggest you just ignore the battery and LEDs for now - but do still install a TRS jack socket so you can add the electronics later. It's more important to get it working right without having to worry about melting something!
 
#9
I'm working on it right now. It's gonna be a little different than usual.

(2) DPDT switches (toggle) for the ABY. Because I don't switch loops mid-song and I can still tell setting without LEDS. A 3PDT switch (stomp) with LED to switch on effects mid-song, and the ability to see the loop status.


What is the purpose of the 100K ohm resistors? Obviously the 12K are for the LEDs. I have a pack of them, but if I don't need them, I have the receipt to return them.
 
#13
Well I finally finished and tested it. The results I wanted, sadly I did not get.

What I wanted:

A w/ loop
A w/o loop
A w/ loop + B
A w/o loop + B
B

Here is what I got:

Switch 1 (A), Switch 2 (A+B), Loop Off - Both Clean
Switch 1 (A), Switch 2 (A+B), Loop On - Both Effected
Switch 1 (B), Switch 2 (A+B), Loop Off - Both Clean
Switch 1 (B), Switch 2 (A+B), Loop On - No Sound
Switch 1 (A), Switch 2 (A/B), Loop Off - A Clean
Switch 1 (A), Switch 2 (A/B), Loop On - A Effected
Switch 1 (B), Switch 2 (A/B), Loop Off - B Clean
Switch 1 (B), Switch 2 (A/B), Loop On - No Effects

It looks like I'll have to go with Plan B, which I should have went with in the first place. Just make a Loop pedal as is, with a second output wired straight from the Input, but with a kill switch right in front of the second clean output.
 
#14
I was under the impression that you were planning on using 3 switches, which in my mind is the minimum that you would be able to use to create what you are asking for. Two for the ABY (as nifty's diagram shows) and then a third for the true bypass loop. I can't see how two would get it done. Maybe if I gave it all kinds of time, but even then I think the operation of such a device would be much trickier than 3 switches.
 
#15
I actually had Brian at Loop-Master build me a pedal like this- it's an ABY with a tuner mute, and a loop for the A output and another loop for the B output. It's a very useful loop box- maybe you could ask him for advice. I imagine you'd definitely need three switches for it.
 
#16
All right, I broke down and drew one.

This is W/O leds so you will have to add another pole to each switch to add an led and do the TRS thing to one of the jacks to switch the battery if you want to do that. Any questions let me know.

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#18
As it stands right now, I can't switch between A and B. I get both signals no matter what position Switch 2 is in. On the plus side, I get 1 clean and 1 effected signal when I engage the Loop now. Cheapbasslovin, I'm not sure how to transpose your diagram to what I currently have. If it's not too much trouble, could you show me what I'm doing wrong with my diagram below?



SOAB2.gif
 

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