Author Topic: Mute Stompbox with Stereo Signal. 4PDT?  (Read 470 times)

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jmo1112

Mute Stompbox with Stereo Signal. 4PDT?
« on: August 21, 2017, 05:22:26 PM »
Hi.  I have a Tele that has both the typical magnetic pickup and a piezo bridge, all of which is carried by a balanced cable to an ABY box, which splits those signals.  I'd like to be able to mute everything BEFORE the ABY (and that muted signal then go to a tuner), and pass that stereo signal through the mute box when it isn't muted so that it can be split by the ABY box.  My tuner won't passthrough a stereo signal, hence the need for a custom mute box.  Would I need a 4PDT footswitch to accomplish this?  Or would a 3PDT work?  And does anyone have a 4PDT wiring drawing?

Thanks.

Cozybuilder

Re: Mute Stompbox with Stereo Signal. 4PDT?
« Reply #1 on: August 21, 2017, 05:58:05 PM »
Any reason why a simple 3PDT won't work?

Some people drink from the fountain of knowledge, others just gargle.

jmo1112

Re: Mute Stompbox with Stereo Signal. 4PDT?
« Reply #2 on: August 21, 2017, 11:03:34 PM »
Thanks for the response Cozybuilder.  Okay, so I'm glad I'm in the beginner section.  I have questions based on what I think I'm reading. 

1. Why are there two options for LED's?  I'm assuming the +9 is the positive side of 9V.  I'm just not sure why there are two.

2.  Where does 9V power come IN to the switch? 

3.  Is the middle row, far right connector the ground for everything in here?

4.  What does GRL mean?

Sorry if these are ridiculous questions.  I'm proficient with a soldering iron and following directions, but not so much with reading a schematic (clearly, regardless of how simple).

Cozybuilder

Re: Mute Stompbox with Stereo Signal. 4PDT?
« Reply #3 on: August 22, 2017, 12:54:06 AM »
1- You don't need any LEDs, you could just use a DPDT instead. However, if you want an indication, its nice to have a visual for both conditions, but perfectly acceptable to just use one of them.

2- If you use a superbright LED, the CLR (current limiting resistor) can be 47K (or larger) and still give a very bright indicator. Using Ohm's Law and a 9V battery, you would be drawing about 191 micro amps, which will last a very long time.

How long? According to the Duracell Copper Top data sheet, a 9V alkaline battery has about 580mAH capacity. Even if you only use half of that capacity before the voltage falls below usable levels, that is 290mAH. Divided by the current draw (.191mA) gives about 1500 hours continuous operation, or about 63 days. Unplug the guitar cable when you're through playing, and it can last years.

3- Ground: sleeve of the guitar input jack, and 0V from your 9V power source.

4- CRL = my dyslexia on full public display  :icon_redface:  This should be RCL (Resistor Current Limiting) or CLR (Current Limiting Resistor). You can use whatever value that gives enough light on stage. I like blue and green 3mm waterclear LEDs with 47K.
Some people drink from the fountain of knowledge, others just gargle.

jmo1112

Re: Mute Stompbox with Stereo Signal. 4PDT?
« Reply #4 on: August 22, 2017, 03:50:37 PM »
Ha.  Well that makes a bit more sense.  Parts have been ordered.  I guess we'll see how this goes.  Can't promise I won't be back here in a few days trying to clean something up. 

jmo1112

Re: Mute Stompbox with Stereo Signal. 4PDT?
« Reply #5 on: August 26, 2017, 03:02:51 AM »
Well... I got everything except the LED working.  I just have one LED, to indicate for on.  I'm not exactly sure what I did wrong here. 

Just to be clear...
The bottom right connector goes to the negative leg on the LED.  The positive leg goes through a resistor, and from there to the positive leg of the DC jack.  And the ground from the DC jack goes to the middle right connector.  Is all of this correct?

Cozybuilder

Re: Mute Stompbox with Stereo Signal. 4PDT?
« Reply #6 on: August 26, 2017, 10:28:54 PM »
That sounds right. Be sure the LED works, and that the switch isn't 90 degrees off.
« Last Edit: August 26, 2017, 10:38:21 PM by Cozybuilder »
Some people drink from the fountain of knowledge, others just gargle.

jmo1112

Re: Mute Stompbox with Stereo Signal. 4PDT?
« Reply #7 on: August 30, 2017, 06:14:36 PM »
Well it looks like my LED was bad.  Got some new ones, tried them out, and all works well.  Thanks for your help!

jmo1112

Re: Mute Stompbox with Stereo Signal. 4PDT?
« Reply #8 on: September 01, 2017, 10:50:59 PM »
Okay.  Not totally out of the woods yet.  2 issues:
1. My LED turns on for the opposite channel.  I want the LED on when I have the guitar muted/sent to the tuner.  Currently it's on when it's passing signal.

2. I have a little bleed happening between the outs.  Any way to fix that?

***edit***
I think I just figured out the LED issue.  Not so much on the bleed.
« Last Edit: September 01, 2017, 10:58:39 PM by jmo1112 »