Hey guys,
I'm installing an Elma 4 pole, 3 position rotary (non-shorting) switch on a Neotek Series 1 and I'm having some grounding issues that I can't make sense of.
The switch is wired at the control room output of the master section and is unbalanced signal. Switch position 1 goes to a pair of balancing cards on the output of the console, connected to a pair of powered monitors. Switch position 2 goes to a pair of TS jacks on the console, connected to an unbalanced power amp.
I'm getting a buzz from whatever pair of speakers is not getting signal. i.e. When on switch position 1, the speakers connected to switch position 2 will buzz. Both output jacks are connected to chassis ground. On the switch side all grounds (input & both outputs) are tied together. If I jumper (with alligator clips) the input poles of the switch to whichever switch position is not in use, the buzz will go away, but of course, then I have signal at both pairs of speakers. :-\
The amp is on the same circuit as the console, but I've tried ground-lifting it anyway, without any luck. I've also tried disconnecting all grounds at the switch, as well as lifting both outputs and sending the input to chassis.
One strange anomaly: The passive monitors have a low freq. ground hum/buzz whereas the active monitors (which receive their input from balancing cards in the console) have more of a white noise sound and it's only in the left speaker. I've had this same white noise sound happen with these when ground was not connected properly at the output cards, and solved it by tying them to chassis, but that's not working here.
I'm not sure if there is some other type of component I need to add to make this work, or if there is some special grounding trick that I'm missing.
One thing I just thought of while typing this up is that the switch is balanced and my signal is unbalanced, so I'm only using half of the switch. Could Poles A&B be isolated from C&D? Currently I'm using A for Left and B for Right; should it be A-Left & C-Right? I'm going to try this out next unless someone tells me otherwise!
Thanks for your help!
I'm installing an Elma 4 pole, 3 position rotary (non-shorting) switch on a Neotek Series 1 and I'm having some grounding issues that I can't make sense of.
The switch is wired at the control room output of the master section and is unbalanced signal. Switch position 1 goes to a pair of balancing cards on the output of the console, connected to a pair of powered monitors. Switch position 2 goes to a pair of TS jacks on the console, connected to an unbalanced power amp.
I'm getting a buzz from whatever pair of speakers is not getting signal. i.e. When on switch position 1, the speakers connected to switch position 2 will buzz. Both output jacks are connected to chassis ground. On the switch side all grounds (input & both outputs) are tied together. If I jumper (with alligator clips) the input poles of the switch to whichever switch position is not in use, the buzz will go away, but of course, then I have signal at both pairs of speakers. :-\
The amp is on the same circuit as the console, but I've tried ground-lifting it anyway, without any luck. I've also tried disconnecting all grounds at the switch, as well as lifting both outputs and sending the input to chassis.
One strange anomaly: The passive monitors have a low freq. ground hum/buzz whereas the active monitors (which receive their input from balancing cards in the console) have more of a white noise sound and it's only in the left speaker. I've had this same white noise sound happen with these when ground was not connected properly at the output cards, and solved it by tying them to chassis, but that's not working here.
I'm not sure if there is some other type of component I need to add to make this work, or if there is some special grounding trick that I'm missing.
One thing I just thought of while typing this up is that the switch is balanced and my signal is unbalanced, so I'm only using half of the switch. Could Poles A&B be isolated from C&D? Currently I'm using A for Left and B for Right; should it be A-Left & C-Right? I'm going to try this out next unless someone tells me otherwise!
Thanks for your help!