Question:
Ok, so I built my own pedal that will mute my guitar. I got it to work, but when I turn the switch off so it mutes the guitar I still get a slight "bleed" if you will. You can still hear it ever so faintly. Is there a way to get it to fully mute? I attached a schematic so maybe that will help.
Answer:
What kind of footswitch and parts did you use? I dare say the problem is in the footswitch. If you have an indicator LED, you'd just need a 3PDT. For no indicator LED, a DPDT would work perfectly and both will eliminate any bleed.
Answer:
All of the footswitch stuff was found either in my garage, off my old amp or at radioshack. I got the plastic project box at the shack, the toggle switch in my garage and the 1/4" jacks from my old amp. Does it just need to be a stronger switch?
Answer:
I don't know if "stronger" is the right word so much, as just a switch that is better-made. If it was found in your garage, there's no telling what it came from or was intended for. Perhaps it was just a toggle switch for turning on a light or something like that. What I do know is that 3PDT (3-pole double throw) and DPDT (double-pole double throw) switches eliminate this problem and aren't terribly expensive. You said you have a toggle switch? In other words, hand-operated? 3PDT's and DPDT's come in both footswitches, toggle switches, rocket switches, etc. Radio Shack should have them. They're the way to go.
Answer:
I'll try finding one. The last time I checked RadioShack I couldn't find what I was looking for, but I have to go in there tomorrow, so I'll take another look. Thanks a bunch for the help.
Answer:
If you can't find them there, you can check www.smallbearelec.com. Steve Daniels keeps a really great running operation there and has good prices on the majority of his stock.
Answer:
Originally Posted by kquamme94 I'll try finding one. The last time I checked RadioShack I couldn't find what I was looking for, but I have to go in there tomorrow, so I'll take another look. Thanks a bunch for the help.
Yes, I believe that a DPDT switch would work. Right now, the signal is going through the ground side of the circuit. For most purposes, you don't need to worry about this, but for a mute, it could cause this effect. Most amps have the input tied to ground before the preamp with a large resistor. If you were to only mute the 'hot' side of the input, I suppose it would be possible that the signal is going through the ground, through the large resistor, and then into the preamp.
With a DPDT, you can disconnect both at once, and should eliminate the problem. However, if you are using a metal project box, you will need to have a way of isolating the ground side of the jacks. Otherwise, the extra signal won't go through the switch; it can go out of the jack, through the box itself, and then back into other jack's ground. (That is just something to watch for.) If you have a plastic box, you should have no problem with that.
I hope that made sense to you.
Answer:
Cut one of the wires off of the switch, and move it away from the switch. If you don't get signal through, it's just a crumby switch, not a problem with your design, which is what i'm suspecting.
You shouldn't need to disconect both wires. Anyone who believes otherwise, thing about what happens with an instrument cable when just one wire breaks off the solder terminal of the plug. You don't get any signal. This is the same concept. Electricity requires a complete circuit to flow. If there's only one wire effectively coming off of your pickup, how are the electrons that leave the wire in the pickup getting back into it or vica versa. So tht00's explanation doesn't really make any sense.
So if cutting the wire gives you what you want, you just need a better quality on/off switch. Even radioshack sells these fairly cheap. You don't need any thing with any more poles or positions unless you want to add an LED indicator. If you do want to add an LED, here's a few different ways you could do it. Let me know if you want pictures of any of these, or need an explanation on how to choose the right resistor value.
(1) Get a double pole on/off switch. Set up one half of the switch just like the picture. For your LED circuit, you need a battery, LED, and possibly a resistor depeding on the LED and the voltage of the battery. All three components go in series, and the on off switch goes somewhere in the loop. Only thing critical in how you set it up is to make sure the flat side of the LED goes towards the negative battery terminal.
(2) SPDT. Connect the tip terminals of the jacks with one wire, connect the grounds with another (or use a metal box). Connect the center terminal of the switch to ground. Connect one side to either of the "tip" lugs. the other side should go to the negative side of an LED. On the other side of the LED, put a resistor, on the other side of the resistor, the positive terminal of a battery, and the negative terminal of the battery goes to ground. This one might cause some problems with a guitar with active pickups, but probably won't.
(3) multicolor LED, DPDT switch. Use one half of the switch to make an on/off for the "hot" side of the signal. Just use the center terminal and either of the sides, and leave the other side disconnected. Mutlicolor LED's have 3 wires. I'm completely sure of this, but I think they typically have two wires on the positive side, and one on the negative. Connect these two wires on the LED to the two sides of the switch, and connect the middle to power (or ground if I'm wrong about how the 2-color LED's work). Throw in the series resistor and make connect the other side of the LED to the appropriate side of the battery.
To make any of there methods more sophisticated, to were the LED is always off if the input cable is unplugged, get a stereo jack for the input side. Connect everything else the same, except wire the negative terminal of the battery to the ring of the jack.
Answer:
Originally Posted by jbm222 Cut one of the wires off of the switch, and move it away from the switch. If you don't get signal through, it's just a crumby switch, not a problem with your design, which is what i'm suspecting.
You shouldn't need to disconect both wires. Anyone who believes otherwise, thing about what happens with an instrument cable when just one wire breaks off the solder terminal of the plug. You don't get any signal. This is the same concept. Electricity requires a complete circuit to flow. If there's only one wire effectively coming off of your pickup, how are the electrons that leave the wire in the pickup getting back into it or vica versa. So tht00's explanation doesn't really make any sense.
Well, actually (at least in a tube amp; I havn't studied transitors or the theory behind them) the only requirement for the signal is the voltage to the grid. No current actually flows through the circuit. The voltage changes, and the electrons flowing from the cathode to the plate mimic the (AC) voltage applied at the grid. Voltage can (and will) change regardless of if the circuit is open... and the change in voltage is what is fed into the amp. The way amps are set up, I don't think there is any current through the pickups except what goes through the resistor of the input to ground (R11; see diagram).
Guitars that arn't grounded will work (but are unusably noisy). I would guess that a similar situation would be possible through the ground with the input not connected (a possible signal through the 'ground' side of the input). Maybe this will be easier to understand (red arrows = signal path):

Can anyone confirm this?
Answer:
The other night I got a chance to revamp the pedal. I picked up a push on/off switch from RadioShack and replaced the old switch with the new one. That helped but it was still a little noisy, so I grounded both of the jacks to the screws that keep the cover on the plastic project box and I think that did the trick. Thanks for all the help.
Answer:
It sounds like he has it working, but...
Looking at his drawing, the switch is disconnecting the ground side. In my experience, that does not completely mute a signal; there is still enough voltage potential at the other end to hear it thru an audio circuit. Usually when you want to mute a signal in a low current circuit like that, you short the signal wire to ground, not disconnect anything. I would recommend connecting the "hot" and ground to the switch - in the closed position the signal is shunted to ground, in the open position it has no effect. If you get a clicking or popping noise when switching, try a 1 or 2 meg resistor across the terminals.
Answer:
I think I get what your saying... is this drawing correct?
Answer:
Originally Posted by kquamme94 I think I get what your saying... is this drawing correct?
Yes, that should work.
Answer:
Yes.
Answer:
Yey! I resoldered/rewired it and now it does exactly what I want it to. Thanks again to everyone who contributed!