Hi Friends,

I provide a LIVE PA service for a charity once every month.

I purchased the below kit about a year ago as got sick and tired of using sub standard gear.

Below is what I use, had my real problem today and would need some advice as to if the unit is faulty of user error.

Allen and Heath ZED 12FX
Peavey CS 1400
Electrovoice SX 300 x 2

I am using 2 Shure SM58's and 2 Condenser Mic, Samson and Electrovoice

The problem was only experienced today, whilst the performance was going, on one of the channels it starting to make a paper cracking noise. I killed all the channels down and 1 by one worked out it was coming from 2 channels.

On that channel every time I hit PFL and put the earphones on, volume up, all I could hear was crackling. This was coming out to the speakers.

There was me thinking i bricked the speakers also. I tried to move the mic xlr to a spare channel, same problem.

After a few minutes with the xlr left out, I put it into the same channel and no problems. This is weird or what or normal for a unit going bad.

The amp is on 1 notch below -6 volume, on the mixer I turn the gain up until the meter comes to 0 on peak.

Any advice appreciated as don't want the same think to happen again next month. If you need more info please ask as I am a newbie.

Thanks

Were those inputs by any chance the condenser mics?
And was it a damp day?

Condensers are a bit notorious for getting a bit noise prone if they pick up some condensation or other damp.

Regards, Dan.

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Audiophiles use phono leads because they are unbalanced people!

Hi thanks for the reply, the problem one was the shures, condensors were fine.

It's good that you're getting noise in the headphones, at least you can experiment without setting the whole lot up.

I'd be systematic at this point:

Check all the other channels.

Experiment to see if the built in reverb is involved.

Switch off phantom power and check again.

Are you using any outboard effects, graphic EQ, etc.?

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Ohm's Law states, "Your PA isn't as powerful as you think it is".

Hi, I tend to agree with Mr. Shufflebeat on this one..the effects , when they go (as has happened to me) make the sound you describe. Dave

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My head hurts!

... and in addition to what's already been said... check out your mic cables too.

Hi guys, thanks for the positive feedback, pardon the pun.

I use a lot of effects on the board, mainly use the arena effect. The effects were on when the noise started to occur.

If the effects channel is broke how will I know? If one channel is broken how will I know.

It appears this happened when the unit was being used heavily but this should not happen with a 1 year old Allen and heath. Aren't they supposed to be rated a good mixer, hence I bought this over sound craft.

If it is not happening now on the channels, could this be intermittent, if so what causes it.

Sorry for 100 questions but I don't get how you can damage the mixer from normal use, with not dust conditions etc, me being main user.

Thanks

Don't be too quick to jump to conclusions... are you sure the problem emanates from the EFX engine?

As has already been said you need to do some systematic testing with different mics, cables, phantom on/off, EFX on/off, different input channels etc etc to pin down precisely where this is happening.

Once you've definitely identified the problem area do come back. Even if you can't make the problem reappear do let us know. That in itself may be a clue.

Cheers mike, will do and get back to you.