Orion Xtreme 800.4 one channel heavily disorted

[Chopperbuilder]

I'm working on an Orion Xtreme 800.4 that has heavy distortion on only the right front channel. I've ran some voltage checks on some of the various components but all have checked good. Obviously I am over looking something. Anyone have any thoughts on what I should check?



I've have another thread going regarding the burnt voice coils in my 336is mid woofers. I had this amp sitting on the shelf and was going to use it to replace the one I am currently running. I did a bench test on it and found the distortion issue.

 

[Perry Babin]

Does any combination of switch/pot position on the amp make a different in the distortion?

 

[Chopperbuilder]

When I flip the switch from stereo to sum L+ R or mono, it is very slightly less distorted. Other than that no combination of switch/pot position makes any difference.

 

[Chopperbuilder]

Perry, sort of off subject, if you would please take a look at my Orion NT6 blown voice coil post and tell me what your thoughts are...particularly to my question about the RCA cables. I asked that question because I did find an issue with one of the cables, actually it was the cable that feeds the channel which had the burnt out voice coil.

 

[Perry Babin]

For this amp, you'll have to find the corresponding points in the amp and compare them to see where the distortion begins.

I posted in that thread that the voice coil could have been damaged if the channel was oscillating. That can be caused by an open shield.

 

[Chopperbuilder]

I attached a photo of the audio section of this amp. Can you show me where I should start?


On that voice coil thread, I seen where you had posted that. I triple checked the RCA ground shields. What I did find was with one of the RCA cables, the ground wire was touching the power wire inside the connector. It has the type of connector that screws together.

 

[Perry Babin]

Set the amp to feed each channel by itself and to full range.

Feeding only one RCA input at a time, find and mark each op-amp output that has signal with only that RCA fed. Do this until you have all 4 channels mapped out.

 

[Chopperbuilder]

Do you happen to know which pin/pins on the op-amps I should check for signal?

 

[Perry Babin]

All of the output pins.

 

[Chopperbuilder]

I did that. So I now know which output pins on which op-amps have signal for for the RCA feed with the distorted signal. What's next?

 

[Perry Babin]

Are all op-amp output terminals on that channel perfectly clean?

 

[Chopperbuilder]

What settings do you recommend to set the scope on for this test?

 

[Perry Babin]

Timebase of 2ms but the vertical amp setting depends on the signal level on the op-amps. You want about 3 divisions ± of the reference line.

 

[Chopperbuilder]

The attached photos didn't capture exactly what I'm seeing on the scope screen but would call the sine wave in the 2nd photo distorted at all?

 

[Perry Babin]

If you can clearly hear the distortion, I wouldn't expect the signal to look anything like a good sine wave.

 

[Chopperbuilder]

The top and bottom of the sine wave in the second photo isn't solid as it appears in the photo... the center part is more translucent, almost separating into two lines.


The sound distortion is severe.

 

[Perry Babin]

How does the distortion on the output compare to what you're seeing in the preamp section?

 

[Chopperbuilder]

I may have just found the problem. Working on uploading the photos.

 

[Chopperbuilder]

Here are the sine waves of the 4562 op-amp on that distorted channel.

 

[Perry Babin]

There is no indication of which pin is which image.