cd player - xlr output buzzing

My guess would be that your adapter cable already shorts pin 3 to pin 1 (most xlr-to-rca adapter cables and adapters do that). And I would further guess that the reason for the problem is that the cd player, which has a low 22 ohm output impedance, cannot tolerate having its "cold" output signal (xlr pin 3) shorted to ground, with the only current limiting being provided by that output impedance.

Using an adapter plus an rca-to-rca cable would be no different, electrically.

I would suggest asking the cdp manufacturer if the player can tolerate having xlr pin 3 shorted to ground.

Shorting one side of a balanced input to ground via an adapter would not be a problem, but I would avoid doing so with any output unless the manufacturer confirms that it is ok, and/or the output impedance is known to be considerably higher.

To answer the question in your preceding post, the wiring configuration could be checked with a multimeter or ohmmeter.

Regards,
-- Al

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?

"there is buzzing and harmonics in the speaker output at low volumes."

"It is okay at higher volumes."

It sounds a little like a ground loop and this may be the smoking gun

"The only reason I don't use the RCA output is that it runs directly to another amp/system and the RCA cable is far longer than the XLR->RCA cable.

If the other >>"amp system"<< is in another room ... it is probably plugged into an outlet that is fed from the opposite side BUS in your main panel box that your main system's outlet is fed from

Main system and preamp plugged into outlet fed from BUS A ... other amp system in the other room plugged into outlet fed from BUS B ...this will create a ground loop

Try disconnecting the RCAs that feed the "other system" in the other room from your preamp and see if the noise goes away

Hi Dave - thanks, too, but tried disconnecting everything except the cd player, preamp and speakers. Used the RCA output from the cd player, no probs. Used the XLR output, same issue. It seems like the preamp can't handly the XLR output of the cdp, whereas my headphone amp can. A pity because the XLR output of the cdp actually sounds better than the rca output....

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