Atma-Sphere in CO?

 @atmasphere I saw in listing by TMR advertised as mk3

If it had rounded corners on the power supply cover its a Mk3 at least.
Any idea of the condition of the tubes? The main reason we've found that people let go of our amps is that they don't realize how far downhill the tubes have gotten. The second reason is that they buy a new speaker to which the amp is not compatible. In your case, that is no worries as your speaker (or its predecessor) was designed with M-60s that Israel used to own.

@atmasphere Interesting. I do believe there is at least one bad tube in the amp. I had a channel go out and was able to flip which channel it was by switching out the tube complement. I got a new set of 4 output tubes from TMR and rectified the problem, but did not consider switching out all the tubes. I’ll see if they have a full extra set before returning...

If the 6SN7s get weak, the amp can sound a little sleepy or dead. Its worth it to make sure they are all good!

@atmasphere Unfortunately The Music Room wouldn't provide any extra tubes... they do have a tube tester, but stated:  "while we can test the tubes, that may not really give you the information you are looking for, we can test to see if it is working, and get some idea of the condition but this won't tell how it sounds or how much use they have had. In addition, this would also take quite a bit of time to test that number of tubes."  They then offered to put in an order for a new set of tubes if I wanted to pay...