Sound Skulptor forums
Build help and troubleshooting => MU524 Vari-Mu Tube Compressor => Topic started by: soundguy937 on July 27, 2025, 12:46:40 AM
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I cannot get my DMM to show -2 when adjusting the TR4 VREF. It goes to zero before the Trim pot starts clicking to let me know I've reached max adjustment. Am I missing something?
Do I need to adjust the output potentiometer back to zero (instructions does not mention to do this)?
Also do I need to pick a sidechain setup step to go with(i.e. -3db @ -2v, or -6db @ -3.6v)?
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Check the value of TR4 (5k, marking 502) and R32 (2k7, red, violet, black, brown, brown).
What is the max negative value you can get on TP6 (trimmer fully CCW) ?
Do I need to adjust the output potentiometer back to zero (instructions does not mention to do this)?
No, the outpout pot is set to get 6.0VAC on the XLR with the jumper removed.
Also do I need to pick a sidechain setup step to go with(i.e. -3db @ -2v, or -6db @ -3.6v)?
You need both to be set.
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Yes the value of TR4 is marked 502, and the R32 Value is correct.
Also I really missed the negative sign on my DMM, it was placed directly below the DC symbol and I didn't notice till I came back to it :o
the max value was something like -7.32
I just finished setting it up, Thanks for your response. I suppose I just needed to step away for a bit. I just ran music through it and it seems to respond like a compressor. I have not listened to it yet as I have not put it in the correct spot near enough to an input. I will come back if it does not sound correct (hopefully in the next few days as I am 40 yrs old and started back to college this summer and it's finals week).
Again thank you, much appreciation
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(https://fonts.gstatic.com/s/e/notoemoji/16.0/1f44d/32.png)