EAR 890 crackle and hum


Having trouble in having trouble with an EAR 890.  It crackles in the super tweeter and hums in the midrange.  I have two 890's.  One is dead quiet.  Placing the second one in the exact spot, same connections, same PC, same tubes and the noise persists.  Sent off for service and no issues found.  Contacted EAR and virtually no response.  I run with an EAR 912 through Tannoy Kingdom Royals.  The noise is present when used in single stereo or in mono block configuration.  Noise is audible from 10+ feet and is a big distraction.  The noise is there with volume off, on low and between songs at higher volumes.  Any ideas?

drpat
drpat, do the amps share the same power outlet? If not, I'll suggest you try the offending side using the outlet that powers the non-offending side. Other than that, I see nothing that may account for such anomalous behavior.

You may want to try a different amp from the EAR amps. Quite a puzzler.

Best of luck,
Dan





Dan, I have taken the offending amp and placed it in the same spot, same IC's, same PC, same tubes, same pre, etc and even all by itself(the good one is totally disconnected) the noise persists

p
You could try a new set of tubes or swapping the tubes. I had an 890 and had some issues. Turned out to be a pinched wire during assembly. It was so bad that the it cut through the insulation and was shorting one channel out. The amp sounded awesome but it took a second tech to find the issue.
Joeinid, thanks for the thoughts.  I have tried different tubes.  The one 890 plays perfect but the other( using the exact same tubes) persists in its noise.  When sent off for service, the issue isn't recreated on the shop table.  Granted, they aren't using the same speakers for testing.  Regardless, one amp is perfect, the other is not.
I see that your speakers have a ground terminal on the rear, in addition to the high frequency and low frequency + and - terminals, with the use of the ground terminal being described as "optional." This is just a wild guess, but if by any chance you have been connecting that ground terminal to the amp chassis, or to some other point on the amp, try disconnecting it altogether.

Regards,
-- Al

Almarg, no I have not.

drpat,

Not sure where you are located, but the best tech I know is Ben Jacoby in Brooklyn, NY.

He was able to find/fix problems others missed.

http://www.highendaudiorepair.com/ben-jacoby.html


DrPat,

What happened to your noisy 890 amp?