RF T600-4 Problem

[vypr]

Hi again,
I have an issue with a T600-4 in my car. The problem is that I get alternator whine in the front right speaker, the tweeter only when the heater or defroster is on. There is no whine in any of the other speakers. The front speakers are RF T1652-S Components, left and right. Ive swapped RCA inputs and the sound stays on the same channel. Ive swapped amps with a crossfire 4 channel and the noise is gone. Ive tried regrounding the amp and no change, It just started doing it about a month ago. Amp is not running bridged its rinning the components up front and 6X9's in rear. The amp is not under warranty. I have checked continuity on the RCA shields on the amp inputs and the all are connected. I dont know where to go from here. I dont wanna replace that amp, it really sounds great just when im not playing anything with the heater, fan or defroster on, I get whine through the front right speaker. Thanks for your help

[Perry Babin]

Try connecting a different speaker to that channel. Do not use the wiring in the vehicle and disconnect the wires that are connected to those terminals now. Use a short length of speaker wire to go from the terminals to the test speaker. Does the noise remain?

[vypr]

Hi Perry,
Thanks for your reply, I am at work now I will try that when I get home and post back the results.

[vypr]

Perry, Ive taken one of my old stock speakers and placed a long enough wire on it so I can listen to it while im inside of the car and so I can press the accelerator. I hooked the speaker up to the front right channel of the amplifier I ran the wire outside of the car and through the window. I started the car and turned on the air and the rear defrost, I was able to hear the alternator whine in that speaker really well, nothing in any of the other speakers. So yes the noise remains.

[Perry Babin]

This may be difficult to troubleshoot. Do you have a way to trace the signal audibly? I think it would be difficult to find any other way.

[vypr]

Perry, What do you mean? Do you mean leave the amp installed in my car, start it up, open it up and trace the noise with a scope? Im not sure what you mean

[Perry Babin]

You'll almost certainly have to have the amp installed in the vehicle to troubleshoot it.

To troubleshoot it, you'll likely need something like the Radio Shack mini amplifier and test leads for it. This is generally better for troubleshooting strange, low level noises than a scope.

Before you do any troubleshooting in the amp, you should disconnect all but the test speaker from the amp and try both RCAs plugged into the noisy channel. It's very strange to have noise like this on only one channel.

If you can find absolutely no way to get rid of the noise, get the schematic from Rockford and send me a copy.

[ppia600]

If the noise isn't caused by the speaker lead being next to the blower power wiring it will be caused by the rca shield for that channel being weak. I would assume it would be the passive crossover picking up noise through its inductors but you said you already ran the speaker wire outside the car so...

[vypr]

yes, I ran the speaker wire out of the car and to a different speaker, one that i can hold in my hand and i was able to hear it with the heater on, also the rear defroster causes it. Anyway before i went to work this morning I started my car up and opened the trunk and I pulled the RCA's off of the front channels and the whine got really loud, I put the right front RCA back on and there was no change in the noise, but when I put the left one back on it got quieter and the whine was back in the front right channel. Same thing with the rear channels but it didnt matter which one I had plugged in as long as the left or right was plugged in the noise was quiet. Didnt try it yet with none of the RCA's plugged in just did the front and then the rear as explained above. That amp is relatively newer I doubt fosgate will give me the schematics since it is an 09 model but who knows.

[vypr]

Also, shouldent the channels be quiet without the RCA's attached to them?