Recent Posts1
MU524 Vari-Mu Tube Compressor / Re: Light Hiss/Noise
« Last post by egelmett on June 18, 2025, 02:42:17 PM »FYI - Still having issues.
I have two MU524. The "Left" one is the one with intermittent snaps and pops and noise - it comes and goes. It happens whether in "IN" or "Linked" modes.
The "Right" unit is my control source. It's silent...no noise. It did have a problem with the P1 pot going bad - replaced.
What I did on both was to tape the entire underside (toward the components) of the cover plate leaving only the screw holes and their conductive pads exposed. That worked for the "Right" unit.
But, for the "Left", it's been a long-running process of swapping components between the two devices to try to find the component responsible for the intermittent noise.
Along the process, I did swap the voltage converters, but was not the cause.
Other attempts:
Lightly sanded the board contacts (to the 500 box), lightly added solder to the header pins connecting to the front plate (thinking poor connectivity), tried three different 500 chassis, tried moving positions in Midas L6 (and removing other devices around it), Swap tubes, swap C4 with C7, replace all electrolytic capacitors, replace C17, remove and resolder T1 & T2, swapped U3 & U1 between units, swap tube mount and socket between units, replace C10, C11 & C12, reflow ALL solder joints.
I will still swap U2 & U4, one at a time, to continue the process.
I'm probably forgetting other maneuvers as it's been a year-long process...could it be a bad trace on the PCB? That's where my head is going. It only starts when the device is well warmed...but a reflow of ALL solder hasn't helped...neither has a very tight mount of the support posts to the chassis (thinking ground issues).
I'm about ready to hit JP up for his repair service...I'm so damn frustrated at this point!
I have two MU524. The "Left" one is the one with intermittent snaps and pops and noise - it comes and goes. It happens whether in "IN" or "Linked" modes.
The "Right" unit is my control source. It's silent...no noise. It did have a problem with the P1 pot going bad - replaced.
What I did on both was to tape the entire underside (toward the components) of the cover plate leaving only the screw holes and their conductive pads exposed. That worked for the "Right" unit.
But, for the "Left", it's been a long-running process of swapping components between the two devices to try to find the component responsible for the intermittent noise.
Along the process, I did swap the voltage converters, but was not the cause.
Other attempts:
Lightly sanded the board contacts (to the 500 box), lightly added solder to the header pins connecting to the front plate (thinking poor connectivity), tried three different 500 chassis, tried moving positions in Midas L6 (and removing other devices around it), Swap tubes, swap C4 with C7, replace all electrolytic capacitors, replace C17, remove and resolder T1 & T2, swapped U3 & U1 between units, swap tube mount and socket between units, replace C10, C11 & C12, reflow ALL solder joints.
I will still swap U2 & U4, one at a time, to continue the process.
I'm probably forgetting other maneuvers as it's been a year-long process...could it be a bad trace on the PCB? That's where my head is going. It only starts when the device is well warmed...but a reflow of ALL solder hasn't helped...neither has a very tight mount of the support posts to the chassis (thinking ground issues).
I'm about ready to hit JP up for his repair service...I'm so damn frustrated at this point!
