I play in a band and for our p.a. Setup we have a powered mixer running into passive speakers. The powered mixer only has 4 channels and we want more. I've been given non-powered mixer with 12 channels. So my plan is to take the left and right main XLR outputs from the non-powered mixer and plug them into the XLR inputs on channels 1 and 2 on the powered mixer, panning hard left and hard right respectively.

My only concern is that according to the manual, the powered mixer has +15 V phantom power on the XLR inputs at all times. So is it safe to do as I described, or will I damage either mixer?

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    This 100% depends on the design of the sub mixer and you should check the manual (most manuals can be downloaded from the manufacturer web site). Ideally you would not have phantom power turned on for channels that you've plugged a sub mixer into, but many sub mixers are designed to block the phantom power safely. Another option is to get XLR to 1/4" adapters and not even use the XLR inputs on the powered mixer, if it has other input options. Dec 3, 2018 at 18:31

2 Answers 2


Be careful. Apart from the phantom power issue, the XLR outputs on the new mixer are very likely +4dB line level. The XLR inputs on the powered mixer are expecting a microphone signal, several orders of magnitude lower.

Nothing is likely to explode. But the levels will be grossly mis-matched.

Use the Line inputs on the powered mixer. Doubtless 1/4" jacks. If the new mixer has jack outputs as an alternative to the XLRs, use them. Otherwise, you will need to make up an adapter cable (or two).


I would agree with Todd on this and not use the XLR inputs on your powered mixer, if it only has XLR inputs then the adapters would be a way to bypass the Phantom power. I'm doing a similar modification right now to expand my 6 channel Yamaha Powered mixer, using an unpowered stereo 6 channel mixer into a single channel on the Yamaha that has dual 1/4" line inputs (as well as an XLR jack). I send both main outs from the expansion mixer into the dual line In's and leave all of the stereo pan settings centered. I leave the powered mixer tone settings centered and make my adjustments on the expansion mixer. It has been working fine and expanded the power mixer to 11 XLR inputs. The only hassle is that all inputs from the expansion mixer share the single monitor level and effect (reverb) controls on the power mixer channel. But to be safe it never hurts to check the manual or contact the manufacturer. Good luck.

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