Potato Cakes said:With the 500R trimmer installed, I am a bit lost with trying to match the two channels and have that shown on the metering. I can get the same reduction in levels with adjusting both of the trimmers, but then the metering is off, and I am using a nice set of Sifam VU meters. When I adjust the meters to match, then the zero is off. The mechanical zeros are set correctly. I'm chasing my tail trying to find a way to set these properly. Does anyone have any suggestions on a procedure to set this? Is there any use to adding a trimmer to the stereo link connection?
I’m not sure where the 500R trimmer is. To get a handle on the level and threshold you need two external meters. One meter at the output and one to measure internally.
I started by measuring the level at the input. If both channel match, measure after the input pot. If those match move through the circuit. I made sure that levels were matched when measuring at the input to the Compression pot.
Then check the compression steps. If the gain reduction when measured at the output matches well enough for you then adjust the output for unity gain.
I prefer to know where the threshold is. I think having both the Input control and the compressor control is confusing and redundant. I’d view the Input control more as a compression range extender than an Input control.
When doing this I’d remove all the diodes to make sure they aren’t skewing the results
Once that is done then work on calibrating the meter to match the external measurements.
I didn’t have much luck with stereo link. Judging from other posts I don’t think many have. I’m not using it. I certainly wouldn’t use it while testing individual channels. You don’t want any interaction between channels for testing.
PS if you have pots it might remove some variables by starting with pots.