platzhalter back to start platzhalter
platzhalter aboutplatzhalter studioplatzhalter musicplatzhalter vst-pluginsplatzhalter custom compilations platzhalter links platzhalter contact platzhalter
platzhalter

Slaughtering a Yamaha MT8X into a nice 11 channel mixer

got this from the bay for 16 eur plus shipping.

Channel 1 was blown and only delivered loud noise. tape unit also didnt work.

after a look inside and trying to put it apart i first thought 'OMG, just put it back on the bay, may someone other try to fix it.' ... 4 very large PCBs and LOTS of cables, looked a bit like the inside of my memorymoog some years ago. I first wanted to make sth new out of it, synth, drummachine, controller ... but the hardware didnt look right for that.  

after some thinking and looking i was curious if i could extract just the mixer which is, in my opinion, quite neat, interesting and highquality. It has 4 triple EQ and 2 aux-channels (both mono send, stereo return), 1-7 is mono, channel 8 is stereo and it has a stereo-tape in. That means 15 inputchannels in total :)

it also has 4 groups, don't know what for, must be for this tapebouncing thing... i am not familiar with that...

the input/output jacks are directly on the board, no wiring, short signalways. All connectors wires-functions are printed on the pcb so i also spotted two +14/0/-14 jack which are directly connected on another board which i dont use. Now comes the interesting and BAD BAD part of the story:

yamaha printed the WRONG voltages on one of the connectors: +14 was -14 and vice versa.

After blowing some fuses in my PSU I found this out by following the voltage lines on the pcb and looking at the polarities of the elcos.

 
after the mixer was running i wanted to fix channel 1. the insert was working, meaning that it must be the mic-preamp. There are a couple of these amps on one of the 3 unused boards supllying the tape-preamps. i transplanted one of them on the mixer and - it luckily worked :)

 

  

spare parts - i guess i wont run out of connectorwires (useful!) small caps and lownoise-opamps in the next years.

i especially like this tiny 8 channel slider board.

 

  
Now the onboard PSU was to powerful for the mixer alone, without the other 3 boards the 14 volt connectors delivered >19 volt, i quickly switched it off again. Looking at the datasheets of the only 3 different opamps on the mixerboard i decided 15 volt would also be ok, so i could use an old pcb i had left over with a nice ringtransformator... of course with a suitable fuse.

Update: the psu i used as replacement seemed to have some damage resulting in zippy noises on the mixer-outputs. i had to replace it with a standard +12/-12-psu. maybe the 15 volt were to high, dont know but now it worx without noises :)

 

  

Thats it. There are some holes now in the front but who cares. The good part is, it lost a lot of weight and consumes MUCH less energy now.

With a bit of looking around i guess i would have found a cuter mixer for the 22 eur i payd. but i consider this as practical environment protection, making useful tools out of broken things, others would throw away. And of course i learned a lot, e.g. not to trust a manufacturers connector-labeling :)

 

  
platzhalter
platzhalter