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cd player - xlr output buzzing

currently using the xlr output of this cd player;
http://www.cattylink.com/page153.html

to the RCA input of this preamp;
http://www.cattylink.com/page309a.html

I am using a generic female xlr -> male rca cable. Each time I start the system up, there is buzzing and harmonics in the speaker output at low volumes. It is okay at higher volumes. I tried to see if it is the tubes, or the output, but nothing alters the problem except using the RCA output of the cd player into the RCA input of the preamp.

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.

Is there any possibility that the higher vrms of the xlr output is causing the buzzing? Would it be wiser to simply buy an xlr female to xlr male adapter and then use an RCA->RCA cable in conjunction with the adapter to see if the buzzing continues?
bleoberis
atmasphere's avatar
atmasphere
11,793 posts
 
Check and see how the adaptor is wired. Sometimes if pin 3 is left floating, the result is a buzz. So the adaptor should have pin 2 tied to the center pin of the RCA, pin 1 of the XLR tied to the RCA ground, and pin 3 of the XLR tied to pin 1 of the XLR. That should sort it out.
bleoberis OP
33 posts
 
hmm how do i do that? it is an actual 1m long cable, do i need to open it up somehow?
almarg's avatar
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almarg
9,670 posts
 
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
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