RAA4200 amp whining at no load/input

[psyrex 10+ year member]

I have a MB Quart RAA4200 purchased new. I've only owned it for two months and haven't really used it since I'm still working on the install. I've been trying to debug this problem for the past week and finally gave up and am asking for help.

The amp WHINES... I never noticed this before probably because it's always in my trunk. I noticed this as I was trying to debug a hissing problem. The conditions:

- engine is *not* on

- this is the only amp plugged in

- there is no input (I pulled out the RCAs)

- it's just power, and then 6x9 speakers plugged in on the rear deck directly over the amp (so a very short run of cable)

It sounds like the 2500Hz test tone. It's not particularly loud, but it's pretty distinctive.

Any thoughts? Do I just have a bad amp or is this normal?

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[JimJ 5,000+ posts]

I know this doesn't fix the problem, but when do you have the interconnects unplugged during normal use?

 

[Loud3 10+ year member]

Does the amp have a cooling fan, perhaps?

 

[psyrex 10+ year member]

JimJ: I guess what I should've said is that the whine persists, whether the input is plugged in or not. I had pulled them out to test if it was caused by the input line catching outside signals

Loud3: No, there's no fan.

 

[zachzchw 5,000+ posts]

What happens when you turn the engine on?

What kind of deck do you have?

 

[psyrex 10+ year member]

What happens when you turn the engine on?What kind of deck do you have?

I just tried it, and the whine is still there (just harder to hear over the engine, but same pitch, same volume).

So far, I've individually pulled out and put back in speakers and input, I've cranked the gain up and down, and I've tried it with both the engine on and off -- and the whine is not affected by any of it: same volume, same pitch, same annoying problem that I can't fix //content.invisioncic.com/y282845/emoticons/furious.gif.fc81ca146dbff91fede3ed290dbc4f4c.gif . The only thing I haven't tried yet is checking if the ground connection is good since that requires taking alot of time to remove most of the trunk lining to get to my ground connection.

For the deck, I have my factory radio/CD changer (for the stock functionality), and a CarPC with sound going through an Extigy. But neither of them affect the whine, whether plugged in to the amp or not.

 

[zfactor 10+ year member]

its a quart.. i hate to say that but they had major issues with the amp line.. i know so many people that have expensive paperweights now since rockford has washed their hands of repairing them... and maxsonics doesnt touch them either according to john (one of the owners). make a new jumper for ground just dissconnect it at the amp and use a temporary wire... give the amp a different ground and see if it goes away. this and popping noises were all to common with these... i have 2 of the qaa amps sitting dead that all rockford will do is exchange them with refurb'ed lightning audio amps.. yes you read that right

also if possible can you try a different source unit?? maybe have a freind use his car and hook your amp to his rca's and see if the noise is still there.. try disconnecting the remote wire and give the amp a constant 12v from the power wire... at this point its a needle in a hay stack game...try everything

 

[psyrex 10+ year member]

its a quart.. i hate to say that but they had major issues with the amp line.. i know so many people that have expensive paperweights now since rockford has washed their hands of repairing them... and maxsonics doesnt touch them either according to john (one of the owners). make a new jumper for ground just dissconnect it at the amp and use a temporary wire... give the amp a different ground and see if it goes away. this and popping noises were all to common with these... i have 2 of the qaa amps sitting dead that all rockford will do is exchange them with refurb'ed lightning audio amps.. yes you read that right
also if possible can you try a different source unit?? maybe have a freind use his car and hook your amp to his rca's and see if the noise is still there.. try disconnecting the remote wire and give the amp a constant 12v from the power wire... at this point its a needle in a hay stack game...try everything

Thanks for your reply. I got the MB Quart since I thought they were supposed to be good, but now I'm finding threads about how they're not. Sucks. I know I have to comprehensively test every little arrangement individually, but I've had no luck so far and was hoping for more advice.

Thanks, I'll just keep testing. I hope there's nothing wrong with the amp.

 

[zfactor 10+ year member]

why not take the amp out of the car and hook it up on a bench or have someone do it then see if it still whines... i wish i dodnt have to say what i did but i am pissed off at rockford now... qaa series 1800$ retail exchange for a lightning strike amp i mean come on wtf seriously.. no comparison there...

 

[zachzchw 5,000+ posts]

Thanks for your reply. I got the MB Quart since I thought they were supposed to be good, but now I'm finding threads about how they're not. Sucks. I know I have to comprehensively test every little arrangement individually, but I've had no luck so far and was hoping for more advice.
Thanks, I'll just keep testing. I hope there's nothing wrong with the amp.

Easiest way to determine if its simply the amp or not- try it in another vehicle.

See if you still have the same problem.