41

MU524 Vari-Mu Tube Compressor / Re: MU524 is noisy

« Last post by JPK on January 19, 2026, 10:56:59 AM »

Check if any component is overheating, U2 in particular.

42

MU524 Vari-Mu Tube Compressor / STEP 6 OUT 1Vac

« Last post by FX on January 19, 2026, 10:54:40 AM »

Bonjour JP
Suite au premier test des deux MU524, j obtiens des résultats identiques sur les deux en terme de niveau de sortie aux pin 2/3 sur les deux entités.Autour de 1,...Vac
voici les relevés
 MU N°1
0/V+ =15,2 VDC
0/V- = -15,5 VDC
0/B+ =46,7VDC

TUBE 2->6V DC OK
TP1=41,4 VDC
TP2= 40 VDC

TP1= 0,37 VAC
TP2= 0,57 VAC
TP3=0,5 VAC

OUTPUT MIN= 1,34 VAC
OUTPUT MAX POT 10= 10,6 VAC


CHANGE COND

TP3=0,160 VAC
TP4=1,8 VAC
TP5= 1,8 VAC
TP6= -2,5 VDC
OUT= 3,7VAC
METER -6

T1 IMPEDANCE OK

---------------------------

MU N°2

0/V+ =15,2 VDC
0/V- = -15,5 VDC
0/B+ =46,7VDC

TUBE 2->6V DC OK
TP1=41,1 VDC
TP2= 41,1 VDC

TP1= 0,39 VAC
TP2= 0,37 VAC
TP3=0,521 VAC

OUTPUT MIN= 1,07 VAC
OUTPUT MAX POT 10= 11,6 VAC


CHANGE COND

TP3=0,06VAC
TP4=0,680 VAC
TP5= 0 VAC
TP6= -14 VDC
OUT= 1,5VAC
METER MAX -20 

T1 IMPEDANCE OK

les 2 T1 ont bien la face vers l arrière.

Si vous avez des pistes je suis preneur a 200%

je vous en remercie

43

MU524 Vari-Mu Tube Compressor / Re: MU524 is noisy

« Last post by OttoWei on January 18, 2026, 09:56:23 AM »

No, I have tested some more now and the tube does not affect the problem at all.

44

MU524 Vari-Mu Tube Compressor / Hiss when recording

« Last post by Pierro on January 15, 2026, 09:21:00 AM »

Hello JPK,

I built my 524 few month ago and it works perfectly when i send it line signal but adds a LOT of hiss when i try to record through it, so much that it's unusable this way. The is is just white noise.
Set up: microphone -> 1073 preamp -> MU524

Bringing up the input doesn't add noise but the output on 0 is already too much and bringing it up just adds more hiss.

Do you know what could be the issue?
Thanks a lot

45

EQP501 Passive Equalizer / Re: Switch issue

« Last post by JPK on January 13, 2026, 03:19:40 PM »

46

EQP501 Passive Equalizer / Re: Switch issue

« Last post by Horicios on January 12, 2026, 12:09:01 PM »

I changed the switch and now it works perfectly...thanks

47

CP4500 Stereo Bus Compressor / Re: Bad power voltages and reversed THAT1246

« Last post by JPK on January 10, 2026, 09:49:53 AM »

48

CP5176 FET compressor / Re: Modification HPF cp5173

« Last post by PMswing on January 09, 2026, 07:34:19 PM »

C'est parfaitement clair ! Merci !!!

49

CP4500 Stereo Bus Compressor / Re: Bad power voltages and reversed THAT1246

« Last post by MRMNW on January 09, 2026, 06:51:03 PM »

All calibrated and working now, thanks JP

50

CP4500 Stereo Bus Compressor / Re: Bad power voltages and reversed THAT1246

« Last post by MRMNW on January 09, 2026, 04:03:17 PM »

Bingo. Thank you. Another mistake!