Tascam 688 & Ground Hum Problem

[mixmasterdsr]

Hi everyone..

I just recently bought a Tascam 688 on eBay, and after several months, I finally had a free moment to plug it in, and it seems that I am getting a ground hum from the main outputs, which are RCA. I checked to make sure it wasn't the cables or my other mixer or monitor setup, by plugging into my Tascam 4 track, which sounds noise-free. Since this unit has quite an extensive digital patch bay, I'm wondering if there's something turned on which shouldn't be, monitoring-wise - for instance, sending an aux or a channel to the mains that has nothing plugged in to it. I'm wondering if anyone here has any experience with this unit and can tell me what to look for. I emailed the original seller (this unit is brand new looking) to see if he knows anything, but I don't have high hopes since so much time has passed. Any ideas? Thanks!

[mixmasterdsr]

Hi, I am still searching for an answer to the line noise / ground hum issue I am having. I took my Tascam 688 in to a local repair shop here in SF, and the tech is claiming that the issue is with my XLR cables. The issue is that when monitoring back from TAPE, I am hearing a buzzing sound when the unit is not playing (as soon as program material begins playing the noise is no longer noticeable)... this is with EVERY CHANNEL being monitored from the TAPE setting. the weird thing is that it should not be picking up noise from bad cables regardless, and IF the cables were bad, I would think when I am monitoring from INPUT of the XLR the line noise would be there as well, but it is CLEAN?the noise is only when monitoring from TAPE. The first time they tried to give me the unit back they claimed it was *fixed* and I'm not sure what they did. This issue is driving me crazy and I'd love some suggestions of things to try. I have tried narrowing down the cables used and it just seems in general that the more cables I have plugged in to the unit, the more line noise accumulates. Seems to be a grounding issue. Any ideas??

[mixmasterdsr]

Seriously, what are some effective ways to deal with ground hum in the studio. Anybody? Is this thing ON????