Polarity of RFZ console inputs/outputs
« on: April 03, 2021, 06:34:39 PM »
I have a 1980s RFZ MP-4084 console from the DDR. I'm in the process of replacing some of the din, trennklinke and tuchel connectors, and I'm having a difficult time determining the correct polarity. Someone already installed XLRs for the mic inputs, but I'm not sure they did it correctly, because it was done differently in different sections.

The console is in three sections, the main unit (8 channels plus master etc) and two additional 8-channel units. Pin 2 from the mic input xlr goes to different pins on the mic preamp modules (KV80) in the different sections. The line outputs are mixed up as well.

Perhaps someone here could help determine the answer to the input polarity by looking at this part of the schematic? If you look on the left, AB5 and AB3 are the two input pins on the preamp module. Currently, some of the mic inputs are wired pin2 to AB5, and some are pin2 to AB3. Or maybe it doesn't matter as long as the input and output on each channel are matching?

Re: Polarity of RFZ console inputs/outputs
« Reply #1 on: April 03, 2021, 06:37:28 PM »
Here's the full schematic for the KV80 preamp module.


Re: Polarity of RFZ console inputs/outputs
« Reply #2 on: April 04, 2021, 04:34:55 PM »
Checking polarity is pretty straightforward. Use a two channel scope. Put channel one on your input signal. Put channel two on your output signal. Send 1K to the desk. First check your test setup, you should have two sine waves with matching polarity. Then the same when you test a path. Reverse wiring as appropriate.
Dont have a two channel scope? Then maybe you are not equipped for the task.

Re: Polarity of RFZ console inputs/outputs New
« Reply #3 on: April 04, 2021, 05:17:15 PM »

AB5 -> a -> + of signal or in phase
AB3 -> b -> -  of signal or out of phase.

Best regards!

« Last Edit: April 05, 2021, 03:32:47 AM by jokeramik »

Re: Polarity of RFZ console inputs/outputs
« Reply #4 on: April 04, 2021, 06:52:03 PM »


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