Powercab Plus Combo Jack Input - 2 guitar? in Powercab Posted May 3, 2019 Playing 2 guitars through the same loudspeaker means you have no frequency separation, hence it will sound utterly garbage, because that single speaker can't work for both guitars, unless they are playing exactly the same thing, at the same time, with same amplitude. Typical thing you may get it's one of the two guitarists being buried or totally cancelled as the other one kick in with some distortion or screaming solo. Also not a great move in terms of input saturation, clipping and speaker lifespan. If you both are playing some clean stuff, it can work some way, but you will be still getting that "ping pong" fight between the two signals.