Troubleshooting EAD DSP-7000 - Static/Whirring Sound
Recently my EAD DSP-7000 started to malfunction, with the "Lock" indicator light staying lit as soon as the DAC is powered on, even though no digital source is being fed into it. The sound produced by the DAC is a very loud and unpleasant static combined with a coil whine and industrial-sounding whirring (played through my speakers). This is the only sound the DAC’s analog output produces, and it’s constant regardless of whether a digital source is being fed into it or not.
I used to experience this issue periodically, but it would always resolve after I left the DAC plugged in overnight. After the issue resolved itself, if the DAC was left plugged in, it would never experience the issue again. It’s only when the DAC is unplugged for a significant period of time (i.e. a month or more) that the issue returns. The most recent time I plugged in the DAC, I experienced this very issue, except it didn’t resolve itself after being plugged in (turned on or turned off) for a couple of days.
Does anyone know what the cause of this issue might be and how much it would cost to repair? Would contacting Noble Electronics be my best bet? Or could I have my local audio shop do the repair?