Broken Preamp: M-Audio ProjectMix

[samth3mancgp]

Hey I have an M-Audio Projectmix I/O with a preamp that has some real nasty static on channel 6 ALL THE TIME! I have dealt with it for about two years now and seem to remember an M-Audio tech support dude telling me that it was probably a burnt out IC.

I have attached a short MP3 of the static sound. I've heard this thing probably takes the cheap TL072 op amps? This thing's pres sound god awful, I use all external stuff using the line inputs anyway, I just need to get the ch 6 running again so I get that extra channel back!

 

[Aoresteen]

Do you have a schematic?

 

[dejf76]

Hi man,
I've found the same noisy sound on my 8th channel as you record on your 6th channel. Have you found out any solutions? Which IC is broken? Is it really TL072 op amp broken?

thanks a lot for your answer..
dave

 

[samth3mancgp]

Way late on this reply... Sorry

I need to be more patient about waiting for replies to threads here. I stopped watching this thread after a day or 2 and forgot about it thinking i would get no help. Looks like some has arrived though!

Do you have a schematic?

No I don't have one. Since M-Audio tech support always strongly advises against DIY fixes, they probably wouldn't send me one. (Not that the schematic would help a whole lot because I can't read them very well at all..)

Hi man,
I've found the same noisy sound on my 8th channel as you record on your 6th channel. Have you found out any solutions? Which IC is broken? Is it really TL072 op amp broken?

thanks a lot for your answer..
dave

Here is a link to a thread that I started at the M-Audio support forum way back in 2009. It has been resurrected multiple times, not always by myself with other people that have had the problem. If you go to page 3 somebody posted some great info including pictures that describes his fix for the problem. He says that it was a resistor that got friend before the op-amp that was causing it. I have not yet tried this fix but I will the next time I am home with the project mix. (I go to school in Tennessee, far from home) Hopefully this quick fix works!!

On another note.. has anybody tried using their ProjectMix as a standalone converter by routing the preamp inputs to the ADAT output? I don't think that this is possible to do within the driver routing software? Maybe if the unit was hooked up to another computer with another DAW loaded up, then the preamps and project mix A/D could be put in record ready/input monitor in the DAW and be routed to the corresponding ADAT outputs? But then the control surface would only run on the other computer. Unless the control surface information can be run out of the built in MIDI I/O? Oh what a mess that would be.. might as well sell the Pmix and get a Mackie Control and get some other standalone converter..