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Double Bass amp noise

joel kelsey

joel kelsey

Aug 1, 2006
403
4
46
Chicago, IL
www.soundcloud.com
#1
Hello

I recently purchased a Mark Bass cmd p112 combo and now I have some questions. This weekend I got to play through a PA for the first time with this rig and there seemed to be a buzz/hum noise coming from my amp through the PA. The sound guy did not seem to know what was going on so I did not think much of it. I have since noticed that when the amp is on I hear what sounds like white noise coming from the speaker and a louder hiss coming from the tweeter. I tried hooking up a different speaker and I got the same results. The noise coming from the speakers is the same with or without anything plugged into it. The noise does not change when I adjust the volume on the amp either. Should I be hearing any noise through the speaker? Could that noise affect my signal through a PA? How do I go about figuring out what is causing the noise? Any advice would be most helpful.
Thanks
 
#2
Maybe a grounding issue ?? Don't know if this has anything to do with anything but ...... last week on a gig with my AI Coda with a direct out to the PA system, I was getting a high-pitched hum thru the PA speakers until I de-activated the "ground lift" button. I assume that I re-grounded the amp and then everything was quiet.
 
#3
Ideally, you shouldn't hear any noise emitting from your speaker or tweeter with no input, and volume and gains set at 0. That being said, some "cheaper" amps will produce noise simply because of cheaper components. And some tweeters (many I've encountered) DO have an inherent "hiss", but I don't generally use tweeters on bass amps so I just turn them off or down (if there is a tweeter switch or level control).

Now one thing to consider is ground loop hum. Is the power properly grounded. When hooked to the PA, did the sound guy try any ground lift techniques when troubleshooting? I'm assuming you were running from the DI out of your markbass head?

Is the noise you are hearing at home the same noise that was coming from the PA? It could have been a ground issue at the venue (especially in older buildings with less than ideal electrical wiring).

Now I have no experience with markbass products so I can't say if they are inherently "noisy" (and I'm using that term loosely).

EDIT: Something that I just realized. These amps are imported from Italy correct? I'm not well educated on electronics, but perhaps you should check the voltage switch (if there is one) and make sure its on 115 and not 230 (but I'm not even sure if would even power on when set on 230).
 

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