Question:
But would it be possible to have a 3 button footswitch that routes to 3 different preamps, which basically are mutes. (footswitch would toggle whether preamp gets signal from guitar. Also, what about wiring 3 preamps to a power amp. Would I just solder the tips and rings of 3 cords into one? Is there a danger in doing this?
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Originally Posted by BillSPrestonEsq But would it be possible to have a 3 button footswitch that routes to 3 different preamps, which basically are mutes. (footswitch would toggle whether preamp gets signal from guitar. Also, what about wiring 3 preamps to a power amp. Would I just solder the tips and rings of 3 cords into one? Is there a danger in doing this? Is this what you're talking about?
http://galaxy.uci.agh.edu.pl/~bochni...xes_abytm.html
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Originally Posted by BamaBleach Is this what you're talking about?
http://galaxy.uci.agh.edu.pl/~bochni...xes_abytm.html similar, but a little simpler. Id just basically like to figure out a way to wire sort of an a/b/c/ input to a/b/c output with a series of mutes in between to mute a particular channel. Im sure I could make it. Does it exist, or a schematic? I think it could be done fully passively, (which is what I would like if possible). It seems so simple in concept, but I am not sure what footswitches I would need.
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Well, given nothing but A/B boxes, you could do something like this couldn't you?
If that's possible, it should be possible to do what you say.
Unless I'm misunderstanding something.
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that would work, but its a little convoluted. Silly paint drawings of what I would like.
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With the mute switch idea, you thinking you might possibly want to have more than one preamp running in parallel? If so, soldering the preamp outputs directly together is definately a bad idea. I know the signals would not mix the way you would want them to, and it might just be dangerous. At any rate, it's definately not the safest approach.
You could pretty easily build a summing amplifier to mix all three outputs the safe way. Here's a great example. In you case, you could get rid of one of the inputs and the master volume. If you know your power supply is regulated, you could probably safely eliminate one or both of the 47uF capacitors, and the diode (which is there to protect the $0.25 opamp from reversed polarity).
Another reasonable approach might be to build three series effects loops in one box. This would only require 3 DPDT switches and 8 jacks. I'll throw it together in paint here in a second...
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Ok... here it is in silly-paint... I have no idea how much you know about schematics and/or switches... but the dots are switch terminals. If you look at the bottom of a dpdt stomp switch that's about what you'll see. stomping on the switch takes the center terminal in each column and switches it between the top and bottom contact. You need a jack everywhere a signal enters or leaves the box. The tips carry the signal, the sleeves are ground. So all the sleeves should just be soldered together and preferably grounded to the box if it's metal. I should note that there is an alternate method to wire a DPDT true bypass switch that makes it harder to see what's going on but might possibly less prone to popping. If you're interested, ask me about it and i can draw another paint picture.
If you only intend to run one preamp at a time, this might be the easiest, cleanest approach. Combining outputs of all the preamps means combining all the excess noise the generate too. And a good mixer circuit needs to be active (which requires power from somewhere). So this setup would eliminate excess noise and not require power unless you wanted to add LED indicators (which would probably a good idea). The only problem is that you might accidentally turn two preamps on at the same time. This would probably sound horrendously noisy and distorted, but not as bad as if you had two preamps w/ outputs hard wired together and you sent a signal through both of them, and it's less likely to do damage.
If you do decide to go with the mute switch approach, I'd recomend using SPDT switches. These have three terminals and act just like one side of the DPDT. Connect input to each preamp to the center terminal, guitar to one side, and ground to the otherside. This way it mutes it by disconnecting the guitar signal AND grounding the preamp input which will reduce cut out most the noise you might get with a floating input.
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Originally Posted by jbm222 With the mute switch idea, you thinking you might possibly want to have more than one preamp running in parallel? If so, soldering the preamp outputs directly together is definately a bad idea. I know the signals would not mix the way you would want them to, and it might just be dangerous. At any rate, it's definately not the safest approach.
My concern... The mute switch I just don't know what switch to use.
You could pretty easily build a summing amplifier to mix all three outputs the safe way. Here's a great example. In you case, you could get rid of one of the inputs and the master volume. If you know your power supply is regulated, you could probably safely eliminate one or both of the 47uF capacitors, and the diode (which is there to protect the $0.25 opamp from reversed polarity).
Another reasonable approach might be to build three series effects loops in one box. This would only require 3 DPDT switches and 8 jacks. I'll throw it together in paint here in a second... Thanks, thats more what I am looking for.
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one more quick comment... www.diystompboxes.com has a pretty active forum for DIY guitar electronics stuff. There are some very smart, very experienced people on there who know a lot more than I do.