Arc Ref 5se owners

In a word YES. 

This sounds like the 6550 tube. That should be changed after 2,000 hours. It should never cause enough heat to warp the top plate. I would immediately stop using it. I would go to Upscale audio and order a complete compliment of tubes. The 6H30 should have a life of 4,000 hours but since you don’t know where it has been... change them. The best place to get the tubes are Audio Research Corp. They are fully tested and broken in. But they cost more. 

If the tube is running hot after changing... then send it in to Audio Research for repair. You have a world class preamp there it is definitely worth making sure it is operating at peak performance. They can replace the cover as well. 

I owned a ARC Reference 5SE for many years, now I have a Ref 6SE. They are both incredibly good preamps. 

I agree with ghdprentice about the quality of the ARC Reference amps, and replacing the tubes, and purchasing from Upscale.

When I had the 5SE, the poly cover warped over time. I called ARC, and they explained that they used them because they reduced vibration, and that the warping wasn’t unusual. They kindly sent me a replacement, which over time did not warp. Later models used the reengineered poly covers.

I'm thinking your Ref 5SE has the original poly cover.

Appreciate the tips. 

My unit does have the thinner cover. In a post here, a member mused about the different and thicker cover on the ref 6.

To me the units look similar enough I would look into getting a replacement. However, I don't mind leaving the cover off either. 

Interesting that some of the other tube pre have metal covers? 

@ghdprentice based on your experience, a hot running tube indicates near end of life. In that case I will buy a fresh set. Everything seems to work fine. 

Thank you sirs.