# Two Wire Cable: Two Inputs to one output

[partially reposting from Music Stack Exchange (I was told to go here)]

NOVICE QUESTION

My question is simple: If I open up a guitar cable (which uses two inner wires: signal and ground) and connect the signal outputs and grounds together, could I connect that to another cable, therefore get a 2 inputs connected to one output?

My idea is this:

simulate this circuit – Schematic created using CircuitLab

Any ideas? I am trying to be able to plug in 2 inputs and send those to a single output. If this doesn't work, what should I try? Any help is appreciated

• Your syntax is confusing...you are going to open a cable (singular) and then in the same sentence there are multiple outputs and multiple grounds. And then you have "2 inputs" and a single output. Your diagram doesn't show anything marked "inputs", much less two of them. – Elliot Alderson Feb 24 at 20:10
• We do have a schematic editor here. Please try utilizing that so that we have a better visual understanding of what's going on. – KingDuken Feb 24 at 20:15
• @KingDuken I will try that! – Komali Feb 24 at 21:05
• @ElliotAlderson I want to open up the wire and splice a 3rd end onto the first wire (if that helps any more) – Komali Feb 24 at 21:06
• Assuming 'Wire 1 signal ' and 'Wire 2 signal ' are your inputs what do you think happens when one is high and the other low? You can have multiple signals on one wire if for example you have a resistive pull-up and either signal is either pulling down or high impedance however, for example. But you need to think care fully to ensure both signals don't clash with each other. Take a look at $I^2C$ for example. – Warren Hill Mar 6 at 14:01

simulate this circuit – Schematic created using CircuitLab

Figure 1. Parallel connection of two inputs to one output.

If I open up a guitar cable (which uses two inner wires: signal and ground) and connect the signal outputs and grounds together, could I connect that to another cable, therefore get a 2 inputs connected to one output?

Yes.

You forgot to ask would it work.

It might. It depends on what the inputs are.

• Two guitars might work but the volume controls of one will affect the other.
• Two line outputs - pre-amplifiers, guitar pedals, MP3 / phones, etc., driven by transistor or op-amp outputs - may not work well as they may have low output impedance.
• You may get mains hum if you create ground loops through the equipment you connect to.

The right solution is to use an audio mixer which prevents interaction between the two input signals and allows individual volume control.

• Thank you (this makes sense)! Do you have any ideas for modifications to this circuit that would let this work how i want it too? I was looking for a simple (or maybe not simple) soldering project I could do in my free time – Komali Feb 24 at 22:50
• Your question doesn't specify what you want to do with this. Hit the edit link below it ... – Transistor Feb 24 at 23:55
• Could’ve sworn I had written that but I guess I didn’t :I. Edited the post (thanks for the reminder) – Komali Feb 25 at 0:03