Buzzing in Speaker while Playing CDs

I had buzzing from one of a pair of Thiels just from one fleet foxes track, on CD. Tightening the bolts securing the main driver cured it. The other was loose too but didn’t hit the right resonance to buzz. I even asked Thiel what the torque values should be but had no reply. (This was after Jim had died but while they were still trading) but received no reply so I had the guess.

Thank you, yeti42. As soon as I start diagnosing the problem, I will certainly check all connections, bolts, screws, etc. before assuming that there is an issue with the circuitry of the CD transport or the DAC.

As suggested, simply flipping the right and left RCA cables that connect your dac to your amplifier (or preamp) will immediately tell you the source of the problem.  If it stays in the left channel it's downstream (amp or speakers) and if it follows the cable then it's upstream (the cable itself, the dac, or your transport).  Super quick and easy to do, no need to clear the schedule for the day.  

Thank you so much for the response. Life has been busy lately. But as soon as I get back into town next week, the diagnosing will commence.

I finally had some time to work on diagnosing the problem of the buzzing. The first thing I did was to disconnect & clean all of the cables & verified that all of the connections were solid. With the help of my son-in-law we followed the suggestions offered here in the thread. We also connected another CD player to the "suspicious" DAC.

Unfortunately we could not get the buzzing to reoccur. At this point I don't know if the cause of the buzzing was associated with the cables/connections or possibly the dreaded intermittent electrical gremlin. So going forward  I can only wait for the buzzing to reoccur & then to connect the DAC to another CD player.