Lonely Raven
Seasoned Member
  

Jack of all Trades, Master of None
Posts: 3567
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I was exhausted from work, but still spent a couple hours on this last night. Looks like I was right about there being two different buzzes going on, which is what was making this so difficult to suss out.
I repeated all the tests I did before, which was the same thing Steve suggested; starting from the speakers back.
The buzz goes up and down with the volume knob. The ZMA itself is dead quiet - everything starts when connecting outside devices.
Buzz #1, Interconnects acting like antenna - this was the buzz I was getting even with the Oppo unplugged. Since I rearrange my system over the weekend, this buzz has been minimized. It's still there, but I refuse to go to shielded ICs because they sound flatter, like they lose some air. (at least with the ones I have available to me)
Buzz #2, The Oppo. *nothing* plugged into the Oppo except ICs - I get a little of the antenna buzz mentioned above - as soon as I plug in power, I get a heavier buzz that's clearly apparent from the seating position. Again, *nothing* plugged into the Oppo except the ZMA.
If I plug in my old Denon CD player, I only get Buzz #1. It sounds really good on the ZMA by the way, softer and more forgiving than the Oppo.
If I plug my SE84A Zen Amp in place of the ZMA, connected to Oppo or Denon, I only get Buzz #1
Buzz #2 only happens with ZMA and Oppo combo.
I've tried different power cords (factory shielded, DIY unshielded, cheap computer grade, heavily shielded off my Cisco routers). No change to above issues.
I tried plugging both the ZMA and Oppo directly into the same wall outlet - Same buzz issue, with the added bonus of gaining transformer buzz. Tried both devices connected to my Trip Lite isolation transformer, and I was rewarded with the Trip Lite having some nasty transformer buzz, plus the #1 and #2 buzz above.
Again, as I've said before, the ZMA is dead quiet on it's own. The only thing I can figure is that the Oppo has an issue, or is causing an issue when mixed with the ZMA - I'm sort of at a loss for what to do now. Sending Oppo another E-mail to see what they suggest.
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