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Tube-tech MMC 1A supply problem


we have a problem with the supply of a Tube-Tech MMC 1A Microphone Amplifier and Multiband Compressor.
The fuse dirctly blow for the 240V and 270V supply.
Is there anybody who can helps us with the schematics ?


Profile picture for user Boswell
Member for
15 years 2 months

Boswell Tue, 10/02/2012 - 07:50

I assume you are talking about the d.c. voltages at TP201 (+280V nominal) and TP202 (+240V) rather than the a.c. mains input voltages.

I would try contacting Tube-Tech directly in Denmark. I don't know the company (or their products) personally, but from all I've heard, they are a friendly bunch.

Member for
8 years 8 months

wilwin Tue, 10/02/2012 - 14:15

Indeed, its the high voltage DC.
I've contacted Tube-Tech for this, but they do not hand out schematics. They suggest to contact Joystick, but neither they deliver the schematics.
I have replaced Q202 ( BUT11A ) , Q201 ( BUX87 ) and U201 ( LM317T ). Now the fuse don't blow, but TP 201 reads 360V and TP 202 reads 68V.
When I desolder R209, so the line to the AMP section is broken TP202 reads 260V. Difficult to trace the faulty piece without schematics.
I have downloaded the EQ 1A schematics, the supply ( 240v) looks alike but differs.