XLR Out to PA Mutes Cabinet

[MartyDiBergi]

Hello everyone. I have been playing bass for a while, but am relatively new to utilizing an XLR out to the PA for live sound reinforcement when needed, and I know little to nothing about running a PA/mixer/board, and my bandmates, while very musically talented, know little more.

I am running an Ampeg PF-500 with a GK 4x10. When I utilize the XLR out to the PA, the reinforcement over the PA is fine, but it mutes any output from the cab. However, if I mute the channel on the PA, the output from the cab is restored. My goal is to use the XLR out for some additional reinforcment when playing live but to still have output from the 4x10 as well.

I have tried everything I can think of, so I figured I would ask all of you if there is something I am missing or if it is an equiment problem. Thanks for any suggestions or input, and thank you for the wealth of information everyone provides on these forums, I have learend a lot!

[JackTheRipper]

I'm not really familiar with that head, but I briefly reviewed the owner's manual and that configuration should work as you expect. Here's one thing you can try. Take an instrument cable and plug one end in the pre amp out connector and the other in the power amp in connector and see if that helps. I'm just wondering if there is some sort of physical issue inside the head. Even if this works, there is something wrong with your head. Other than that, I don't have any ideas.

--jack

[Floyd Eye]

Get a good DI box.

[TimmyP]

Originally Posted by MartyDiBergi

... if I mute the channel on the PA, the output from the cab is restored.

The mute control on the console cannot possibly affect the amp or the cabinet. It can only be an acoustical problem.

[ggunn]

Originally Posted by MartyDiBergi

...if I mute the channel on the PA, the output from the cab is restored.

I do not know of any way that could happen. My WA guess is that the signal when it comes out of the PA speakers is flipped polarity from the sound from the amp so that from a distance it sounds as if the sound from the cab has stopped.

I have used the XLR out of many amps as a bassist and a sound guy and have never encountered one that cuts off the output from the amp, and I cannot think of a way that the amp's output could respond in any way to the mute button on the PA console. I've not seen everything, of course, but this makes no sense to me.

[longfinger]

Originally Posted by MartyDiBergi

However, if I mute the channel on the PA, the output from the cab is restored.

I don't understand how this can be...

The only thing that comes to mind is that if the PA is very loud, it might be masking the sound from your bass amp so that you THINK it is off, but it is not. However, when you mute the PA, your ears-mind adjust to the lower volume and you can now hear your bass amp-speaker again.

It sounds ridiculous, but it does happen! Especially with loud PA systems.

[MartyDiBergi]

Thanks everyone for giving this some thought. At first, I also thought that the PA was simply overpowering the sound from the cabinet, but after putting my ear literally next to the front of the cab, indeed the mute button on the PA (Peavey XR1212) did affect whether sound was coming out of the cabinet or not.

Funny thing is, I tried putting a 1/4'' adapter on the male end of the XLR out line from the amp into the 1/4'' input jack on the PA, and it it now works perfectly fine. Must be the PA somehow didn't like the XLR to XLR connection. Beats me. Thanks for taking a look!

[marijn van gils]

Is the PA sending phantom power to your head?

[MartyDiBergi]

That was my initial thought, but as of rehearsal last night, phantom power was turned off. I don't remember if it was on when I last tried the XLR-XLR connection.

[Lenwood Dinard]

I think you are on to something with the phantom power. I know phantom kills my bbe AcoustiMax every time. Comes back on when phantom is turned off. Makes sense in the op's senario since phantom is only present on xlr, not 1/4.

[Hactar]

I also initially thought phantom was the issue, but then why would muting the mixer cause the phantom power to change?
I've never heard/seen a mixer that turns off phantom when muting mic channels. That would seem both unnecessarily complex and fraught with clicks and pops...