Sound Skulptor forums

Build help and troubleshooting => MU524 Vari-Mu Tube Compressor => Topic started by: egelmett on December 15, 2023, 03:12:24 PM

Title: Tone Imbalance Between Two MU524
Post by: egelmett on December 15, 2023, 03:12:24 PM

Running my two 524s in stereo, I notice about a 13dB difference in level around 10k. The levels stay parallel until around 700Hz, then gradually differ in the higher spectrum.

I'm thinking I need to redo the setup on both.

Is there anything in the circuit that would most affect the high frequency content?

Title: Re: Tone Imbalance Between Two MU524
Post by: egelmett on December 16, 2023, 08:25:09 AM

I've performed the setup again on both units - same issue. One has a higher frequency output than the other.

I've also tried new cables, different slots pairs...it seems related to one MU524.

Ideas would be appreciated.

Thank you.

Title: Re: Tone Imbalance Between Two MU524
Post by: egelmett on December 16, 2023, 08:51:07 PM

Figured it out.

I had the wrong value resistor at R18. The right value is 470k ohm.

Interestingly, my second kit came with two 470 ohm resistors per the BOM. There should only be one.

When it came time to install R18, I mistakenly used the extra 470 ohm in its place.

I did a 'stare and compare' between my first build and second, and with the BOM, was able to confirm 470k was the proper resistor for R18. Clearly, I had the wrong resistor installed.

Sound test completed: only a .5dB level difference, with a pretty much exact tonal response through both.

Title: Re: Tone Imbalance Between Two MU524
Post by: JPK on December 18, 2023, 06:31:13 PM

(https://fonts.gstatic.com/s/e/notoemoji/15.0/1f44d/32.png)