2. amps-preamps
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Tube hiss - any idea what's causing it?

I own an Eastern Electric M520 integrated amp that I am very fond of. However, recently I have noticed that there is a great deal of rather disturbing hiss eminating from my Omega XRS speakers once I power the unit up. The hiss does not increase when the volume is turned up. It's always there and very noticable during quiet passages. It's definitely a hiss and not a hum.

I checked the tubes and noticed that when I touch or slightly jiggle the front EF86 tubes, the hiss gets louder/softer when they are moved. Could it be that these tubes are going already? I do not have many hours on them. Maybe 100 at best. Should I consider replacing them or perhaps checking the other tubes too - perhaps the 5 AR4 rectifier tubes? I doubt it's the power tubes.

Do you have any thoughts/recommendations for me at this point. I am not sure how to proceed. As always, thanks for your time.
jpstereo

Showing 1 response by slates

slates
35 posts
 

You know come to think of this , I have the same issue in my ARC ref 1, I just bought 4 matched sets of EH 6922 Gold pin, and it seems like one or more has gone microphonic, with my ear up close to the speaker you could hear a hiss and a bit of a hum, the hum being the lesser. Also it's seems less in the right channel than the left. I will be honest, I do not have any dampers on the tubes.
How can I rectify which tube(s) it the culprit? The tubes have less than 10 Hrs on them.

thanks in advance guys.
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