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Topic: Is it possible to send 2 separate signals into guitar amp w/ 1 input? (Read 5401 times) previous topic - next topic
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Is it possible to send 2 separate signals into guitar amp w/ 1 input?

Hi all,

Is it possible to send two separate audio signals (one from a guitar, the other fx from a MOTU output) into a basic guitar amplifier, using a Y-split cable or similar?

In an ideal world:

Guitar  > DI > SPLIT [One signal to the audio desk for FOH speaker send, the other into the amplifier] & an output from the MOTU into that same amplifier.

It only needs to play back a few effects cues, not music, so I'm not too worried about the audio quality.

Any advice would be great.

Many thanks


Is it possible to send 2 separate signals into guitar amp w/ 1 input?

Reply #1
It is never a good idea to connect two outputs together, but there are inexpensive devices called mixers that will do the job. Even less expensive would be to place a resistor in series with each of the sources to safely combine them. Choice of resistor values would control the relative signal strength of the two signals.

Is it possible to send 2 separate signals into guitar amp w/ 1 input?

Reply #2
Also keep in mind the extreme differences in signal levels you're looking at:  output from a guitar is in the microvolt range (especially single-coil pickups), the output from your MOTU interface's line out will be in the millivolt-to-volt range, i.e. orders of magnitude higher.

You will need to greatly reduce the output from the MOTU using a resistive pad, as pdq suggested, before mixing the two signals together.
"Not sure what the question is, but the answer is probably no."

Is it possible to send 2 separate signals into guitar amp w/ 1 input?

Reply #3
Quote
Also keep in mind the extreme differences in signal levels you're looking at: output from a guitar is in the microvolt range (especially single-coil pickups),
And, there are impedance differences...    Guitar inputs are unique.  They are neither line or microphone compatible.    (I thought the voltage is higher than microvolts...  I thought it was nearly line-level with a high impedance load of 1M ohm or more.).

I don't know if there's an existing mixer with both line & instrument inputs, and an instrument output.  It would be an easy thing to build... for someone who knows how to build op-amp circuits.

Someone might make a pedal with an guitar-in plus a line-in, but I don't know.    Almost everything with a guitar-input and a guitar-output is some kind of pedal...

Or, if you have a guitar amp with two inputs (which means it has a little built-in mixer), you can probably plug-in the MOTU, turn down the MOTU output a bit, and turn-down the gain for the channel the MOTU is plugged-into and get a reasonable mix.    Someone might make an amp-head with a line input?

Is it possible to send 2 separate signals into guitar amp w/ 1 input?

Reply #4
What sort of DI box are you using?

A DI box usually has a balanced output to feed into a low impedance mic input.  Connecting the output to an unbalanced guitar input could cause hum in your FOH speakers.  DI boxes also typically reduce the amplitude of signals by a factor of 10.

PS. DVDdoug is correct.  The open circuit output from a guitar can be several volts.

 

Is it possible to send 2 separate signals into guitar amp w/ 1 input?

Reply #5
Hi all,

Is it possible to send two separate audio signals (one from a guitar, the other fx from a MOTU output) into a basic guitar amplifier, using a Y-split cable or similar?

In an ideal world:

Guitar  > DI > SPLIT [One signal to the audio desk for FOH speaker send, the other into the amplifier] & an output from the MOTU into that same amplifier.

It only needs to play back a few effects cues, not music, so I'm not too worried about the audio quality.


Could you be more specific (make, model) about the "basic guitar amplifier"?

Usually, one uses a mixer to feed one amplifier from multiple sources.

Here's an example:

Mixer for feedbug more than one source through an amplifier