ZX475Ti Noise

billyrohm · Post by **billyrohm** » Sat Dec 22, 2007 11:05 am

I have a ZX475Ti and the right front channel(not sure about the rear channels, they arent hooked up) sends a loud sort of pop noise through the speaker. It doesnt even have to be pushed, today it did it with with the volume on my head unit set really low(the sensitvity is really low too, I set it with the dmm method and it was too loud so I lowered it). I thought that it might have some thing to do with the wiring so I switched the speaker connected to that side and the sound stuck with the same channel.

I guess I can switch the RCAs next and see if the sound stays in the same spot. Does anybody have any ideas??

The channel is pushing door speakers only, same speakers as the other channel.

Thanks in advance.

HoseHead · Post by **HoseHead** » Sat Dec 22, 2007 1:02 pm

That's right.
Determine whether the failure is cable or output.
Test as you indicated.
Do you have any other devices or processors between the amp and the HU?

Bruce

andy600rr · Post by **andy600rr** » Sat Dec 22, 2007 1:08 pm

Could be that you have some iron filings in the voicecoil gap of your speaker. Try swapping the speakers side to side and see if the problem follows.

billyrohm · Post by **billyrohm** » Sat Dec 22, 2007 1:41 pm

andy600rr wrote:Could be that you have some iron filings in the voicecoil gap of your speaker. Try swapping the speakers side to side and see if the problem follows.

I did swap the speaker channels and the sound followed the swap it is isolated to one channel.

billyrohm · Post by **billyrohm** » Sat Dec 22, 2007 1:42 pm

HoseHead wrote:That's right.
Determine whether the failure is cable or output.
Test as you indicated.
Do you have any other devices or processors between the amp and the HU?

Bruce

I'll swap the other stuff tomorrow, the amp has to run for a while before it happens.

I have a MTX re-q between the factory head unit and the ZX475Ti.

MW3 · Post by **MW3** » Sat Dec 22, 2007 10:20 pm

Its most likely a bad crossover switch or freq potentiometer on the amp.

Turn the switch and/or potentiometer several times to "clean" it out, it may fix the problem for awhile. But eventually you will likely need to send in the amp for service.

billyrohm · Post by **billyrohm** » Sun Dec 23, 2007 2:37 am

MW3 wrote:Its most likely a bad crossover switch or freq potentiometer on the amp.

Turn the switch and/or potentiometer several times to "clean" it out, it may fix the problem for awhile. But eventually you will likely need to send in the amp for service.

With a bad switch would the problem be isolated to one side?

billyrohm · Post by **billyrohm** » Sun Dec 23, 2007 2:55 pm

MW3 wrote:Its most likely a bad crossover switch or freq potentiometer on the amp.

Turn the switch and/or potentiometer several times to "clean" it out, it may fix the problem for awhile. But eventually you will likely need to send in the amp for service.

Well, I did your trick, along with switching the RCAs, but the noise was gone, not even a hint of it. I'll give it a little while before I get too happy. Hopefully my amp is falls into the not likely, it did sit for around 2 years with no use.

Thanks for the help. I wish that I would have found this place sooner.

MW3 · Post by **MW3** » Sun Dec 23, 2007 4:34 pm

It may be fixed for a few days or a few months, but it will likely come back. It was common issue with those amps.

1moreamp · Post by **1moreamp** » Sun Dec 23, 2007 5:02 pm

MW3 is correct, replacement is the final solution to the issue..

Merry Christmas Morgan....C

billyrohm · Post by **billyrohm** » Sun Dec 23, 2007 5:35 pm

How involved is the replacement?

1moreamp · Post by **1moreamp** » Sun Dec 23, 2007 5:54 pm

The gain pots are double ganged for bass boost and gain. The crossover gain pots are ganged ten deep if my memory is working tonight.

They are simple gain pots with a shaft through them. I simply remove the shaft and then desolder them till they are all out.
I then set the new ones all at one side or the other ( setpoint wise) , just as long as they are all the same. Then I replace them in a row, and re-install the shaft. Then I resolder them all in place. VIOLA ! your done....C

Be sure to make the solder flow to both sides of the board properly, and thats about it. Setpoint alignment and good solder flow rework are the critical issues...

billyrohm · Post by **billyrohm** » Tue Jan 15, 2008 2:58 am

If the noise comes back can I just put the crossovers in bypass and use an external crossover or will there still be noise?

rolandk · Post by **rolandk** » Tue Jan 15, 2008 8:35 am

billyrohm wrote:If the noise comes back can I just put the crossovers in bypass and use an external crossover or will there still be noise?

When the amplifier crossover is bypassed the noise should go away. So, if the noise comes back you could use an external crossover like you said.