Passive A/B/Y

[Deep Blue]

I have seen a few layout files for a/b/y boxes, but they always include circuit boards, which is something I don't entirely understand.

I have a looper that doesn't have a pcb, and works perfectly well.  An a/b/y box seems like it should be no more complicated than a looper - just with two switches and different wiring.  Does anyone have a layout for a passive a/b/y box?  Or should I be adventurous and try to figure out my own?

[80k]

yea it's no problem to do it with just two dpdt switches, or 2 3pdt switches with LED's.

i can't post a picture, so let me try this



INPUT-----x   G      n   m
              m  n      A   B
              G   x---- x--x
                   

Since i can't drop vertical or diagonal lines, just connect all the letters that are the same.

G = Ground connection
A = goes to A output
B = goes to B output
Remember to do diagonal connections between the x's and the G's in the first switch.  
Remember to run "m" from one switch to "m" of the other, and "n" from one switch to "n" to the other.  Same goes with the "x's"

[80k]

doh!  it lost all the spaces when it posted.


okay, these are the two dpdt switches.  add the third pole for the LED if you desire.  

x = input,
G = ground
A = A output
B = B output

connect all the same letters.  (4 x's are connected together, 2 G's, 2 m's, and 2 n's)

x G
m n
G x

n m
A B
x x

[Deep Blue]

If i do use 3pdt and an led, do i need a power supply?

[Deep Blue]

Is this right?  I'm pretty sure its not, but it's a start.  Can you tell me how much of it is wrong?

[moosapotamus]

If you want to have LEDs, you need a battery/power supply.
If you can live without the LEDs, you do not need power.

This page has (among other things) a pretty simple ABY Box (no PCB)...
http://www.kilback.net/homebrewtweaks/pedals/pedals.htm

~ Charlie

[The Tone God]

If i do use 3pdt and an led, do i need a power supply?

You need a power supply if you want an LED. How else is the LED going to get power to light ? I don't see why you need a 3PDT switch though. You can use a normal DPDT switch.

The Super Y article has the schematic and pictures of a passive ABY box that I converted to active.

http://www.geocites.com/thetonegod/

Andrew

[80k]

Is this right?  I'm pretty sure its not, but it's a start.  Can you tell me how much of it is wrong?

yea that looks good.  the only thing you are missing is the Ground connection.  you have the diagonal portion correctly done, but you need to have the ground connection from one of the jacks to connect to either the lower left or top right of the first dpdt switch.

and of course you have to connect all the grounds of all the jacks together.

as for the LED, yea a 9V battery or power supply would be good.  make sure you use a limiting resistor in series with the LED.  a 1K should do just fine.

as for whether you can accomplish the ABY box with LED's but without 3PDT's, i suppose you would then need to use a relay or something?  3PDT's are available through diystompboxes for only 6 bucks a piece, so i would think it's worth the price to make it easier for yourself and use 3PDT's.  unless there is an easier way to do it with DPDT's?

[Deep Blue]

I tried making a layout using 3pdts, leds, and a power supply, but i can't figure it out.  argh.

[The Tone God]

I tried making a layout using 3pdts, leds, and a power supply, but i can't figure it out.  argh.

You don't really need 3PDTs. DPDT are sufficiant for what you are doing. Check the article I mention above. The article has the schematic and pictures of an ABY box complete with LEDs.

Andrew

[Deep Blue]

I'm looking for something passive, though.  I don't want to have to deal with a circuit board.

[The Tone God]

I'm looking for something passive, though.  I don't want to have to deal with a circuit board.

While the article deals with converting a passive ABY box to active the article has the information on how it operated in it's orignal passive form. There is a schematic and pictures of the wiring before I did the converstion. You can use them to build your own box.

Figure 2 and 3 are pictures of the wiring (click on the photo to enlarge) and Figure 5 is the schematic. Thats what the box looked like before I converted it.

Andrew