160 VU(different one) half rack calibration procedure needed

Anyone have directions on how to calibrate a 160 VU half rack?
Got 2 units at a friends place one sounds great the other sounds like it over compresses regardless of threshold level and when the VU meter really hits hard, I.E. shows huge gain reduction, the unit will drop out/not pass audio for quick moment. thinking it's time to check and recalibrate.

Upon Closer inspection, It's as if one unit is operating at a different input level. I can run the same signal out of slow tools, have the controls on both units exactly the same, and the unit I thought needed calibration has a hotter level on the input. It functions exactly the same as the other except due to the higher input, it causes compression to really bottom out and thus release time is much longer. I can't think of why as all componants related to the input seem to be working porperly. I might just pad the input a few DB because when I lowered the fader in Slow tools which affects the output of Slow tools, The compressor works and sounds like the other one. With threshold, compression and output level adjusts this might be the best option. I have checked the unit with 1K @+4 and +4 = )VU so that is in order... hmmmmm

RMS detector.

Thanks keef. :guinness: :guinness:

Look at the circuit and think about it. the RMS detector "tells" the unit how loud the incoming signal is. It tells the 'VU' (HAH!!! -Not a VU at all!) meter how loud the signal is when you look at the input level on the meter. It "tells" the unit how much it should be compressing based on how loud the signal is.

the rest is a VCA and some fluff.

Keith

Ah hah :idea: Simple and effective.... :thumb: