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Wiring Woes-----PSE 9000ex

jbagley

jbagley

Well Known Member
I'm replacing an intercom with an audio panel. The wiring is done and passed the smoke test (no significant miss-wiring). But, i've got something strange going on that causes the ps engineering 9000ex audio panel to run everything in mono except the music. As in, I get left channel only for pilot, co-pilot and radios. But, I hear the music in stereo.

I like to think I have the headsets wired correctly as I just ran new wires and followed the ps engineering manual very precisely. I've looked at the wiring until cross-eyed and can't find any faults. Obviously it has to be somewhere, but I can't find it...

Any thoughts? Words of advice? Call stein? :eek:
 
Just a WAG here, but considering that aviation comm radios are mono, I suspect you may have used one leg of a stereo input for your radio. That, or there is a setting in the audio panel you need to change.
 
Mike,

Makes sense. Except, the pilot and co-pilot mic's also come over in the left channel only.

The audio panel has a "hi" and a "low" input for each of my two com's. My Icom a200 radios do not provide a "low" audio source and the PS Engineering manual says:

Some avionics do not provide a separate audio low, and may introduce additional electrical noise into the system. For best results, connect the audio low from the audio panel to the radio ground, using one conductor of the twisted-shielded cable.
Click to expand...

I don't understand their terminology for "hi" and "low", but the instructions are clear enough. Can someone explain what PS Engineering means by audio "hi" and audio "low"?
 
Boy it's been a while but I believe it's hi = +. low =-. I remember wondering the same thing. I have the 9000 ex also and am pretty happy with it. Wiring was a big challenge for me, and I ended up having to find a gremlin or two.
 
They use audio "Hi" and "Lo" to differentiate "Lo" from "ground".
The term "ground" is for the shield and power ground.
For stereo there is "audio LT", "audio RT", and audio "Lo".
The audio lo and ground (shield) are connected together at the audio panel only.

Clear as mud right.

Do you have stereo headsets ONLY plugged in?
 
Last edited:
Walt said:
They use audio "Hi" and "Lo" to differentiate "Lo" from "ground".
The term "ground" is for the shield and power ground.
For stereo there is "audio LT", "audio RT", and audio "Lo".
The audio lo and ground (shield) are connected together at the audio panel only.

Clear as mud right.
Click to expand...

Thanks. That's pretty much the conclusion I came to. Though, your suggesting connecting the shield and audio low together at the audio panel is different than my reading of the manual:

For best results, a twisted-shielded cable is recommended from the avionics audio source to the audio panel, with the shield grounded at the audio panel end.
Click to expand...

I have the shields connected to ground at the audio panel per the above instruction. What your saying actually makes more sense to me. It seems the manual is mixing terms. Maybe if I just translate "Audio Low" to "Audio Ground" everything will be all ok?

Walt said:
Do you have stereo headsets ONLY plugged in?
Click to expand...

Yup.

Sounds like i'll be re-wiring those 44-pin D-sub connectors. Can't wait. It was a lot of fun the first time. Fortunately, *everything* is labelled. :D
 
I see looking at the pin out for the 900EX that they provided a pin for each audio lo (unlike most of their current units which tie them together external of the unit). I would "suspect" that all the audio lo's are actually tied together internally.

And yes audio low is the same as audio ground, but not the same as "shield ground" or power ground.

Feel free to call me if you need some help.
 
Thanks Walt!

I'm going to look at it with fresh eyes tomorrow, maybe i'll see something that I missed today. I can't imagine that connecting the shields to ground instead of to audio low would have any affect at all. The shields don't actually carry an audio signal and aren't even terminated at the headset jacks. Something else is going on.

Also, since the only part that doesn't seem to work right is "stereo" I might be inclined to use it "as is" in mono mode. I suppose the only danger is that if it is shorted somewhere I might pick up some extra noise?

You know what they say? Education is what you get when you don't get what you want.
 
James,
I agree, the shields will (should) not have any effect. If you have stereo working correctly for music then that would confirm that the headset wiring is correct.
I would just for fun, try the tests using just one headset at a time, and then try it with the other headset, just to take a faulty headset out of the equation.
 
Based on your description of the symptoms, I'd guess your unit will have to go back to PS. Call them for a price if it's out of warrantee.
 
Look at paragraph 3.7.2.1 in the install manual and consider how your wiring of a jack, accidental d-sub pin placement, or stray wire filament somewhere could cause this condition.

If that strikes out, I agree it is time to check the instrument itself.
 
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