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Problem with Ref 5SE

I recently purchased a 5se and took delivery the other day. Did not get a chance to open it up until last night. Upon installing it into system I switched it on and after it warmed up, I was very much interested in hearing how it sounded against my current 27. After listening to several tracks with the 27 I switched pre's and after a couple of minutes playing a CD I got some noise, almost a loud static sound coming from the right channel. It was not effected by changing volume controls or input selector. It went away after 10-15 seconds and then returned. At that point, as it was late, I shut everything down and figured I would take another look in the morning.

This morning I removed the top cover and pulled and reset the output tubes and then the power tubes. I fired it back up and still had the 'static' sound but now it also had a humm, like an impedance type hum and constant. I do not believe that the humm was present last night as it is quite noticeable. 

The static type load noise seemed to have abated after the unit warmed up after maybe 15-30 minutes.

Can I assume that perhaps a tube was damaged during shipping? Do you ARC guys think a new set of tubes will fix this issue or am I looking at something more severe? Any additional suggestions to try and pin this down?

I rerouted the IC going to the amps to get them further away from source IC's and no help...

I am a little bummed, as my initial impression it that it is a leap from the LS27, my current...
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Showing 3 responses by larryi

larryi
3,789 posts
 
Have you tried all of the various grounding options?  Have you tried a cheater plug on the main power cord, etc.?  Hum is usually a grounding issue.  Hum, particularly hum in both channels can be caused by a filter capacitor in the power supply going bad.  Both the 6550 and 6h30 tubes are in the power supply part of the linestage, so they are suspect as well.

The static type noise that goes away after the unit is on for a while can also be a capacitor issue or an issue with tube sockets.  Sometimes poor connection in a socket goes away when the unit is heated.  Your re-seating of the tube curing part of the problem suggests that this might be the case.  I would try cleaning the socket and pins of your tubes.  If noise problems aren't completely cured (good tube linestages  are dead quiet), you should send it in for a check up.
larryi
3,789 posts
 
It certainly does sound like a power supply issue, which could include the 6550 tube.  The advice to look for burned components (check for tell tale odors too) is good advice.  Even if such overheating of a component is not related to your problem, it is good to know if there is other trouble brewing in the future.  I hope it is the 6550 tube because that is an easy fix.  
larryi
3,789 posts
 
I would expect the plastic top to retain heat inside of the component more than would the metal top.  The metal top should do a better job of radiating heat into the air. 
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