Two heads and an A/B box into one cab?

[3'scompany]

This may seem like a dumb question but someone is coming to look at my heads I have for sale and he wants to A/B them simultaneously. Therefore he wants to run them through the same cab, guitar, cable, etc.... So I have an A/B box and would it be a bad idea to run both the heads into one cab so he could switch back and forth between the two? I know that I shouldn't run both at the same time into the cab, but would it hurt it or be generally a poor idea to run them both into the box and then into the cab as to truly A/B them?

 

[Rich_S]

Re: Two heads and an A/B box into one cab?

Are they tube heads? If so, DO NOT use an A/B box on the speaker outputs. The amp not selected will see an open circuit and blow itself up trying to drive current through it.

He's going to have to settle for trying one amp, powering it down, then switching cables to the other, and powering it up.

ANd although the reasons for it aren't as good, do this even if they are solid-state heads.

 

[devastone]

Re: Two heads and an A/B box into one cab?

Yep, A/B'iong the outputs is definitely a bad idea. If your cab is stereo, you can plug one head into each side though and A/B the inputs.

 

[3'scompany]

Re: Two heads and an A/B box into one cab?

Thanks, I kinda figured it was a bad idea but just wanted to make sure. I'll just tell him he's gotta power down and then switch them.

 

[muttonchopsrule]

Re: Two heads and an A/B box into one cab?

+1 to the fellas above.

they make A/B switches for heads to do exactly what you are describing, but unless you have one specifically designed for that, don't do it. you'll cause damage to the amp that isn't selected. then there goes your sale!

 

[Gearjoneser]

Re: Two heads and an A/B box into one cab?

No can do. If amps are running, they need to be seeing the cabinet resistance.
However, you can do it, it you keep flicking the standby switches in between A/B'ing.

 

[baritone]

Re: Two heads and an A/B box into one cab?

The A/B box you have is most likely instrument or line level. Radial makes a some speaker-level switchers - one for solid state amps and one for tube amps.