two guitars in amp with one input

R

ron82

New member
im ready to get laughed at, but i'm really curious if this would work, and/or if it would damage the amp or whatever..

lets say i want two guitars running directly into one amp. but it has only one input, so i use an adapter (2 jacks to stereo)

good? not good? stupid?
 
A better way...

would be to use a DOD passive mixer; it has diodes and all that jazz to keep the signal path going in the right direction. 4 in, 1 out, 1/4" mono jacks. Dead quiet. About $40.
 
You only split signals (ie outputs) with a Y-adaptor, you NEVER merge signals with one......... for that you need a mixing circuit.

You risk blowing up the input stages of your amp doing it the way you suggest..........
 
whow.. not one laugh! ;)

thanks for the info, i appreciate it!

Blue Bear Sound
You only split signals (ie outputs) with a Y-adaptor, you NEVER merge signals with one......... for that you need a mixing circuit.
Click to expand...
ok! good to know! :)
 
Depends on the amp I believe. But you wouldn't use a Y cord into stereo......it would be mono. I don't think guitar signals would damge the amp ( My opinion ) because a lot of amps with two inputs just basically have them in parrallel.
 
I don't understand the blowing up the amp theory. Two signals in parallel would not produce more voltage or current on the merged line than using one signal to start with.
 
The quick answer is here:

Outputs are low impedance and must only be connected to high impedance inputs -- never, never tie two outputs directly together -- never. If you do, then each output tries to drive the very low impedance of the other, forcing both outputs into current-limit and possible damage. As a minimum, severe signal loss results.


The big technical answer (from which the quick answer was taken) is here --> http://www.rane.com/note109.html
 
Thanks for the response. I certainly agree that merging the two outputs will limit the signal.

But the way I read the article, the potential damage is to the low impedance outputs, not the high impedance input. That would make sense in a situation where you are talking about two powered outputs (such as pre-amp outputs), as hooking two powered outputs to each other could damage the outputs on each. (Maybe you could damage two guitars' electronics too by merging them, I don't know.) But I don't see this causing damage to the amp. To the contrary, I think this would limit the amount of current going to the amp's input (which is why you get the limited signal).

I don't profess to be an expert on any of this, so I'm not saying anyone is wrong. I'm just saying that I still don't understand why it would damage the amp. Of course, whether I understand something has no bearing on anything.

With that said, I once tried to merge two guitars with a wye as originally posted, and it just screwed up the sound on both guitars.
 
I'm gonna go with Kelby on this one (cringing like the whipped dog I am). I think it would only apply to powered stuff HOWEVER.......I have seen this done and one problem is that if you turn one guitars' volume off it will also turn off the other one too. I guess that's because a volume control turns it down by shunting the signal to ground so it shuts down anything in that input.
 
I used too run two guitars (mono) into a single stereo adaptor. But it really really sucked, as differentiating the two guitars apart was nearly impossible. Mud, lots of it.
 
I would doubt that it would damage the amp. If you're putting in two guitar signals, and "mixing" them with a Y connector, then the worse that you could do is have a high-peak signal mixing with a low-peak signal. That's technically a short circuit but your amp's input connector is an input node, with ESD buffers (otherwise electro-static shock would blow your speaker right out of the case every time you plugged in). It can handle it.

I would be more worried about if it will have any effect on the pickups on your guitar :) If it's a passive pickup, it should be ok...
 
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