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Stupid ground noise with XLR output

HiFi, LoFi, Tubes, Transistors, ICs, Commercial, DIY

Postby melkior » Fri Dec 06, 2013 12:00 am

Hello all,

Sorry for this not very interesting question, but I have a strange problem with the XLR output of my CD player. I try to explain it :

- I use the CD player with its integrated preamp (Ayon CD5) directly connected to power amps (tube : Cary CAD 211 and solid state : Gamut M200).

- I have no problem with RCA connection between CD player and amps.

- As soon as I use the XLR outputs of the player, I have a buzz in the speakers. It's not a "shhhhhh" in the tweeters (this is normal) but a "Bzzzzzz" in the mid-woofer.

- What is strange is for instance : everything is plugged correctly (XLR) and switched on, I have no noise, perfect. As soon as I press "play" on the Ayon CD5, I start to ear the buzz in the speakers just before the music starts (later I can't ear it anymore of course), if I press "stop" the buzz stop. Ok the buzz is not so loud but..It should not be there.

- Generally I have also this buzzz as soon as the Ayon is switched on and connected through XLR to the power amps, but the previous symptom happen sometimes and sounds strange to me.

- I have had this problem with a lot of power amps, even with high input impedance ones (47 KOhms or 100 KOhms, Ayon has a 300 Ohms output impedance).

As I'm not especially skilled in electronics, I did the tests :

- Removing the ground of the power cable of the Ayon CD5 = no effect (OK I re-connected it immediately after the test)

- on XLR cable : I connected the ground cable (pin 1) to the shell on both ends = no effect

- on XLR cable : I have disconnected the ground (pin 1) on one end = no effect

- I tested with several XLR cable = same problem.

- I checked that all the "pin 1, 2 and 3" on the outputs/inputs sockets were connected without inversion : pin 1 to pin 1 etc..

- I found that a small volume controler (SPL volume 2) connected with XLR between the Ayon and the power amps removed the Buzz (but technically no need for it, the Ayon has already a volume control).

So I don't know what to check anymore according to my poor knowledge. That's not critical as the RCAs work perfectly, but I would like at least to understand what happen.

Thanks in advance for any help
melkior
 
Posts: 9
Joined: Thu Jan 02, 2014 10:37 am

Postby ag » Fri Dec 06, 2013 12:00 am

Hello Melkior,

I found this

02-27-12: Leicachamp
Hi Denon.

You will find a lot of your questions if you email Ayon and ask for an updated instruction book. They have added a section warning about some high powered amps and xlr cables. The updated instruction book only became available last month.

$360 for a quad pair of tubes seems about right. But you mentioned $89-90 for a matched pair in your post.

Also did you upgrade the 6z4 tubes? On the old cd5 I think they were 6x4 tubes. Can someone confirm?
Leicachamp (Threads | Answers | This Thread)


here:

forum.audiogon.com/cgi-bin/fr.pl?ddgtl&1292700942&read&keyw&zzayon

Perhaps you can contact Ayon for the referenced manual. That might add some insight.

Any chance that you got a schematic of the circuits along with the purchase?

Without knowing anything about the unit (other than review raving), based on your description, my best guess is drive motor noise.

Regards,
Ag'
Ag
ag
 
Posts: 533
Joined: Thu Jan 02, 2014 10:37 am

Postby melkior » Fri Dec 06, 2013 12:00 am

Hello Ag, thanks a lot for your answer and for having searched, it's nice from you
Yes I saw this thread on Audiogon and before posting (I also posted a message there a few months ago) Ive really searched everywhere about this problem. I've also contacted Ayon and they say it's tipically a ground problem with the cable. Fine..But ? At least their answer are fast even if they provide no solution
A drive problem would have been a good idea, but I mainly use the player as a DAC with the AES input, and same problem.

I guess theres something wrong with the XLR cabling, or something internaly goes through the XLR when it should not.

Unfortunately, no schematic with the unit, but if it can help I could take some closed picture of the XLR output from inside the unit.

Today new strange bug

the MacBook, used as a source, as soon as switched on generated noise in the speaker (I was with XLR connection between player and amps). This is the first time I have this bug ! Unpluging the USB cable stopped the noise. So I kept the Mac Book connected and switched the XLR to RCA between the player to the amps, and no more noise...

Connections : MacBook USB -> Berkeley Alpha USB converter -> AES/EBU to Dac input of the Ayon -> XLR/RCA -> power amps.

There is obviously a specific ground problem with XLR output of the Ayon, using the internal drive or external one generate the same noise, which disapear when switching to RCA. Im sure it's something stupid

I posted the question on this forum in case of someone already saw this typical bug and found a solution. I also asked in several others english forums, but no way to get any info.

I guess I should bring the unit to a friend diyer so that he can check the internal ground cabling.
melkior
 
Posts: 9
Joined: Thu Jan 02, 2014 10:37 am


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