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Need help solving hum problem

This one really has me stumped....

The system:
Sony SCD-777ES
analog out into Placette Active Line Stage
digital out into Dodson DAC into Placette
Turntable also into Placette
Placette into CJ11A
ALL front end components plugged into Shunyata Hydra PLC

I get constant, low-volume hum when the Placette is switched to either the Dodson OR the Sony analog out, but not when switched to vinyl or any unused input.

The problem is cured when the Dodson is plugged into another outlet (same circuit). Why would the Dodson contaminate the system at all, and (this is the kicker) for two of the sources (itself and the Sony analog out) but not for the phono?

Any ideas? thanks. --dan
drubin

Showing 2 responses by sean

sean
6,231 posts
 
I don't know what to tell you but i can relate. Have had similar problems with a DAC and specific preamp. Out of curiosity, is the Dodson an upsampler ? Sean
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sean
6,231 posts
 
I have tried EVERYTHING known to man to minimize the hum that i'm experiencing. I'm wondering if it doesn't have to do with how these designers are are using the upsampling devices and trying to keep circuitry to a minimum ???

I recently did a "tweak" that did help this out a bit while making other noticeable improvements though. Since this applies to and can benefit ALL systems, i don't want to "pigeon hole" it to this thread. Look for a new thread on the subject in the next 24 hours. Sean
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