I just had a similar problem and it was not the power tubes, it was the driver tubes. It can't hurt to get a new rectifier tube(s) as you will probably need them one day anyway whether it is the problem or not. If the hiss is only coming from one channel, switch the tubes from the hissing channel one by one to the non hissing channel to find the culprit tube, process of elimination. Good Luck!
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.
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.