strange channel

Qu Qu Troubleshooting
1

Hi all
my qu16 has been working all fine although it has pulled a wobly before christmas but was fine afterwards put it down to dodgy electrics. but i have booted it up today all works fine except for channel 16 it has some white noise and when plugging in a mic the mic works but i have to turn the gain down so typically on another channel that works fine to get the equivelant gain would be 27 where on channel 16 it has to be on 3 or 2 to get the equivelant. has anyone got any ideas what has happend to this channel?? or point me in the right direction

Thank You
Carwyn

2

Do you have phantom power on for this channel while using a dynamic mic?

3

Did you happen to engage the compressor on that channel with lots of makeup gain ?

Giga

4

I assume your connecting directly to the mixer and not a remote stage box.

In addition to the compressor check to see if anything else is turned on on channel 16, if so bypass them.

Do you have a lot of boost on the EQ, bypass it as well.

Do you have the FX sends up on channel 16, if so turn them all down.

What mic are you using, I take it that it works OK on other channels.

5

Hi All
thanks for all responses i thought id made it clear in my post but obviously not so here it goes

Input is set to +3 on the gain on channel 16 and it equals to +22 on any of the other channels

all the compressors and gates etc are off with no effects sends etc
i had even re installed the previous firmware on the desk and back to the latest firmware.
and still i had the noise

tody i have managed to borrow a stagebox AB168 from work and connected this to the desk and here is the results from today

so desk is still giving white noise at +3 gain from the input on the desk
when patched to the stage box the issue disapears and when plugging in a mic the gain on the channel needs +22 as per the rest of the channels

i have been using an sm58 for testing pourposes

so by my calculation there is an issue with the input gain on the input of the desk local to the desk and not anywhere else

does everyone agree with me on this

6

I’m going to say that with the results of the stage box test the pre-amp is bad on ch.16 in the board.

Just thought of another question, when using the boards internal mic inputs does the channel metering and PFL metering show that same level difference between channels or were you going just by the main output meters for your reference?

7

input ref and output ref you can see on the input ref of some noise when theres nothing plugged in