Distortion

[sbcjr]

Hello everyone!

I am running the sound system for a small church, and we have a couple of problems.
We are very traditional in our music.  For some reason, everything that comes over the sound system - whether it is the pastor's lapel mic, or a CD, whatever - comes over distorted.  So basically we are without a sound system until this one is figured out.  Occasionally it will crackle and pop, then all of a sudden the distortion is gone.  The mixer is somewhat old, a Peavey Unity Series 2002-16 RQ.  Everything coming through the headphone jack is perfectly clear!
The second problem is that when I use my laptop to record the services, if I run on battery power, it's fine, but when I plug my laptop in, I get this terrible hum.  A quick fix would be to buy a new battery, but I can't afford a new battery right now, and mine lasts for twenty minutes.  

Any help would be greatly apprecciated!

Thank you so much!

God bless,
Steven

[T_Keys]

The second problem is that when I use my laptop to record the services, if I run on battery power, it's fine, but when I plug my laptop in, I get this terrible hum.  A quick fix would be to buy a new battery, but I can't afford a new battery right now, and mine lasts for twenty minutes.

It seems like the "terrible hum" is caused by ground loop, which happens when an electrical system is connected through more than one way to the electrical ground. Ground loop causes a buzz or hum that can be picked up in sound systems. You can eliminate it by the way you design your sound system (google 'ground loop') or by purchasing a professional hum eliminator (they start around $45).

http://www.zzounds.com/prodsearch?cat=2757&form=prodsearch&cat2=&ob=p19&submit=Filter+Results

Hope this info helps some.

[sbcjr]

Hey, thanks for that!  After doing some reading, that sounds like my problem exactly.  Based on that, I think I may know where to start now.

Does anyone have any ideas on the distortion problem?  Do we need a new mixer? Could it be the amp?

Again, thank you so much for that help!

God bless,
Steven

[T_Keys]

I was thinking about the distortion... the only way your board could cause the problem is if it is turned up too high- which I doubt it is. Otherwise the problem could be with bad cables, perhaps the speakers need new cones, or if your speakers aren't powered the power amplifier could be the one at fault...

[CATRON]

IS THE DIST. JUST WHEN A CERTAIN CHANNEL IS PEAKING, OR DOES IT COME WITH LOW VOLUMES TOO?

THIS MAY HELP ME ANSWER YOUR QUESTION.


HOLLA

[sbcjr]

Thank you all for the responses and help!

The distortion occurs at any volume/gain combination, it's just a little more noticable as the volume increases.

God bless,
Steven

[elio]

If the headphone sound is ok, I would exclude problems at the front end of the mixer. Have you tried swapping the power amp out and using a different one?

The problem could be caused by many things: condensation, temperature, dodgy cables... are you using speaker leads to connect to the speakers?

[sbcjr]

Yes, we are using speaker leads... and I don't really have access to another amp...

Thank you!!

God bless,
Steven

[MrTea]

Sounds like you have an impedence matching problem.  Make sure the line/mic switch is set for line for instruments, and mic for Microphones.
You could try purschasing a 'direct box' from a music store and connect to the mic inputs. They cost about $30 to 100.OO.  Radio shack sells 'balance line matching transformers' for about $15.00.  They plug into the microphone inputs.  They work like 'direct boxes', allowing you to plug high impedence mics, and instruments into the microphone connections behind the mixer.

As for that hum problem.  Get one of those 6 outlet surge protectors used for computers and plug all your equipment in to one wall outlet.  This should break the ground loop (hum). If that don't work, you can buy a ground loop isolator from radio shack for $15. bucks and conect it between your laptop and mixer.

Hope that helps

MrTea

[Rown]

I also work the system at our church.I love what i am doing,it is my calling.We for sure have problems to at times.My biggest problem,is doing the week,choir members are back their messing with it,touching things they should not.Then on Sunday mourning,it all messed up,we get feed back and everything.So now we lock it up,only certain people have a key to it.As for as whats wrong with yours,you need to get someone in,to take a look at.If you get into a guessing game,buying this and that,it can get very expensive,have him tell you what need,let him set it,tell everybody else to keep their hands off.Remember,these system will only do but so much.You do not have a serious problem,it will not cost that much to fix