cd player - xlr output buzzing

Thanks Al - the difficulty I'm having in finding any consistency to testing the problem is that when it is connected to the preamp, the buzzing is only at low volumes and sometimes even disappears after a minute or two.

When I use the exact same connection/cable to a Vincent KHV-1 headphone amp, there is no buzzing detectable at all. This would indicate that the cable is possibly fine, but there is something the preamp is disagreeing with?

I can't explain that with any kind of certainty, but realize that when the adapter cable is in place you are most likely connecting one of the two outputs of the driver stage in the cdp (the output which drives xlr pin 3) to the chassis of both the cdp and the component to which it is connected (the preamp or headphone amp). That will expose both the signal return current flowing through the cable, and the output driver device, to noise voltages that may exist on or between the two chassis, as a result of leakage paths between ac hot or neutral and the chassis, and/or as a result of the fact that chassis and ac safety ground are common.

Those noise voltages would figure to be different between the headphone amp and the preamp.

And all of this will be happening while the output driver device is most probably being forced to supply more current than it is designed to supply.

In any event, I would not operate the cdp with xlr pin 3 grounded without first receiving assurances from the manufacturer that that will not cause improper operation, and that it will not cause damage or degraded long-term reliability.

Regards,
-- Al

ahh yes thanks - understand now.

presumably it is safer to simply split the RCA signal?

Even if the manufacturer were to confirm it is okay to ground xlr pin 3, the buzzing would remain nevertheless?

Yes, splitting the rca is perfectly safe, and the very low output impedance of the cdp will mean that any sonic effects of having two loads and two cables attached to each of the rca outputs should be negligible.

Ground loop issues might still be a possibility, along the lines of what Dave suggested. But if need be those could be addressed with cheater plugs, or connecting to different ac outlets, or isolation transformers or other measures that are commonly used to address ground loop problems.

Re your last question, if my theory is correct, then yes the buzzing would remain if you continued to use the adapter cable. It is conceivable, though, that it might be avoided with a specially constructed cable that left pin 3 unconnected.

Good luck!
-- Al

haha we have come full circle (kind of) in that this is the opposite of what Atmasphere first posted!

The key is then whether pin 3 is left floating or not?

I just picked up some of these;
http://www.amazon.com/Hosa-GXM-133-Female-Male-Adaptor/dp/B000068O4D

I know for certain that these have pin 3 tied to pin 1, thus, if the buzzing continues tonight when I test it, I'll have a cable made leaving pin 3 floating.

If that does not work, then I'll have an XLR->RCA yard sale and you are all invite. Beer is on me.

I suspect that Atmasphere was thinking xlr input when he wrote his post, rather than xlr output.

Heineken or Samuel Adams would be great as far as I'm concerned :)

-- Al