Peavey PZS 140RA Mixer Amplifier - Sound interference

[Neil]

Hi All! I am stuck for a solution. I am not an expert sound technician and cannot seem to find the problem. I have constant interference with the sound output of my two Peavey PZS 140RA Mixer Amplifiers.

It sounds like there is an electrical disturbance with the sound. A continuous buzzing sound. The music sound quality is fine. Both have iPods connected to them. However, one AMP has a TV connected as well. The TV sound never has interference. If this buzzing sound starts and I unplug and replug the iPod in, the noise goes away for a while, but then comes back again.

All the speakers are connected to the AMP with proper speaker cable and are connected to the XFMR output using the 8Ω & COM ports

Here is the list of equipment:
System 01
1 x Peavey PZS 140RA Mixer Amplifier

6 x Bose 151™ SE Environmental Speaker System
These speakers are group into 2 x 3 speakers. Each group is connect to the AMP - Zone 1 & Zone 2
Average speaker cable length, for each speaker, is about 80-120 meters

6 x Bose Free Space™ 51 Environmental Speaker System
These speakers are group into 2 x 3 speakers. Each group is connect to the AMP - Zone 3 & Zone 4
Average speaker cable length, for each speaker, is about 60-100 meters

1 x iPod
Connect to the AMP with a standard iPod to AMP Audio Cable


System 02
1 x Peavey PZS 140RA Mixer Amplifier

8 x Bose 151™ SE Environmental Speaker System
These speakers are group into 4 x 2 speakers. Each group is connect to the AMP - Zone 1, Zone 2, Zone 3 & Zone 4
Average speaker cable length, for each speaker, is about 60-100 meters

1 x iPod
Connect to the AMP with a standard iPod to AMP Audio Cable

TV
Connected to the AMP with a standard TV to AMP Audio Cable

Point of note. The iPods are NOT connected to the power souce when connected to the AMPs

What have I done wrong? Am I using the wrong XFMR ports?

Please help....... thank you

[Marty McCann]

Are you going into two separate channels with the I-pod for Left and Right, or are you summing the outputs of the I-Pod? They may not be summable.

[Peter Richter]

Are you having the problem with both systems?

In the system with the problem, is it ONLY when the iPod is plugged in?
If so - have you tried different leads for the iPod?
If it's intermittent and only on the iPod and goes away when you unplug and plug theiPod back, then it could be as simple as a bad lead from the ipod.


Is the iPod on charge when the buzzing happens?
Does the buzzing go away when the iPod is not connected to the charger?
If so then you might need an isolator between the ipod and mixer. (or not charge it when in use)