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Build help and troubleshooting => MU524 Vari-Mu Tube Compressor => Topic started by: egelmett on October 15, 2024, 04:18:59 AM

Title: MU524 - P1 Pot Part Number (10k LogB)
Post by: egelmett on October 15, 2024, 04:18:59 AM

JP,

Could you please share the exact part number for P1? I think I have one going bad...

When audio is input, the levels go to max (12dB) on the meter, and no adjustment of the In pot makes a difference.

I've removed it from the circuit it seemed to test fine (8.5k). It seems that other than Pins 1 & 2 being joined on the PCB, when in-circuit and the control panel disconnected, it should test fairly closely. However, when placed back on the pcb (control panel still disconnected), I'm getting values higher than 10k.

I've checked for shorts elsewhere in the circuit, i.e. R1 and R2 and continuity to pins 7 & 10 on T1, there doesn't seem anything strange but the P1 pot itself.

If I could get the pot part number, or if you are willing to sell a couple, or even have other ideas to check, I'd appreciate it.

Thanks!

Ed

Title: Re: MU524 - P1 Pot Part Number (10k LogB)
Post by: JPK on October 16, 2024, 04:31:21 PM

P1 is a 10k log pot (Omeg LT16BU - 10KB - BUSH C - 6.0MM - SPINDLE F1 - L=32MM)

When audio is input, the levels go to max (12dB) on the meter
Sorry, which meter?

It seems that other than Pins 1 & 2 being joined on the PCB
This is normal. The center pin is connected to the + pin.

The pot must be measured with the front panel disconnected or you will be measuring the input transformer coil. If the measured value of the pot goes from 0 to 10k, varying with the knob position 0 to 10, then it is OK.

If you confirm the pot is damaged, contact me here (https://www.soundskulptor.com/en/content/6-contact) for a new one.