Noisy Audison VRX6 420.1

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I have a unit that producing some high pitch noise(around 4kHz) through each channel,even without the preamp/crossover module installed.All supply voltage measure find for the output stages,driver stage and opamp stages.

Faulty Line Driver Module or PWM Module?Or something else instead?
 
Start with remove modules vrx6cs and vrx6cd
no noise? maybe you have problem with some of the on board switches.
still have noise? remove all the LD1 Power stage driver modules.
if you don't have now any noise place again the LD1 modules 1 at the time.
when you remove or place back any module remote power off.
 

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Start with remove modules vrx6cs and vrx6cd
no noise? maybe you have problem with some of the on board switches.
still have noise? remove all the LD1 Power stage driver modules.
if you don't have now any noise place again the LD1 modules 1 at the time.
when you remove or place back any module remote power off.

Hi,yes I tested with only LD(1.2) modules installed.At first I was hopping the issue was caused by CS/CD module,which will make my job easier but it doesn't:p

Meanwhile,I notice one LD module do produce lesser noise versus other remaining 5 LD module.
 
Hi guys, just joined this forum to ask for help.

I think I have the same fault but on a VRx 4.300 amp.

The high pitch noise starts after the amps been playing for a couple of minutes.

I have opened it up and tried measure with an oscilloscope to capture the noise on the output with out success. Maybe the oscilloscope needs to be isolated for it to work.

I tried using a heat gun on various places to accelerate the process and at one point I did get the high pitch signal. It faded away after a little time (my test bench is in a cold garage)

I measured the transistors at the cooling plate without finding any shorts.
Removed all LD1.2 and checked the transistors on those and all seemed fine.

Here is some pictures
Audison VRX 4.300 output whine - Album on Imgur

And the Audison VRX LD1.2
Audison VRX Linear Driver LD1.2 - Album on Imgur

I have not been able to replicate the high pitch noise with the heat gun, is it possible heating up the amp could have fixed some bad solder?
Anyway I currently have put the amp back together and will put it back in the car to test again.

Leolabs, which is the BJT zener diode you mentioned earlier?
"Update:it was caused by a noisy BJT based zener diode,use for bias of the current mirro"

Best regards
 
Hi guys, just joined this forum to ask for help.

I think I have the same fault but on a VRx 4.300 amp.

The high pitch noise starts after the amps been playing for a couple of minutes.

I have opened it up and tried measure with an oscilloscope to capture the noise on the output with out success. Maybe the oscilloscope needs to be isolated for it to work.

I tried using a heat gun on various places to accelerate the process and at one point I did get the high pitch signal. It faded away after a little time (my test bench is in a cold garage)

I measured the transistors at the cooling plate without finding any shorts.
Removed all LD1.2 and checked the transistors on those and all seemed fine.

Here is some pictures
Audison VRX 4.300 output whine - Album on Imgur

And the Audison VRX LD1.2
Audison VRX Linear Driver LD1.2 - Album on Imgur

I have not been able to replicate the high pitch noise with the heat gun, is it possible heating up the amp could have fixed some bad solder?
Anyway I currently have put the amp back together and will put it back in the car to test again.

Leolabs, which is the BJT zener diode you mentioned earlier?
"Update:it was caused by a noisy BJT based zener diode,use for bias of the current mirro"

Best regards

They are on the LD1.2 module BUT please double confirm with a good working module before you proceed further.
 
I reopen this post because I have the same problem on my vrx 2.250. I think I have identified the two bjts that were mentioned that create the noise (I enclose photos looking for them) are they right? not having the opportunity to replace them at the moment, I can overcome by bypassing the two tantalum consendensors on the sides of these bjt with a capacitor as the forum user said before? what capacitor i should use in case. also can anyone tell me the values ​​of the tantalum capacitors in the front face of the board (circled in the second image) that i can't measure them? thank you all in advance
 

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Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.