5751 tubes and Rogue Tempest?

Samzx12,

I actually never owned the stock tubes. I ordered the M-180's with the GL KT-88's - they were about a $300 upgrade from the stock EH KT-90's.

I would like to be able to give you a more insightful answer regarding the comparison of the two tubes, but I went with the 88's on instinct and haven't actually compared the 88's to the 90's. I asked the guys that own the local audio shop which they thought I should get and after talking about it they recommended the 88's. I don't recall the attributes they mentioned, but I have been very happy with the 88's. I do find that the combination of the 88's and the RCA small tubes I have make for a very musical system with a very low noise floor... I run the system in triode 99% of the time.

Sorry that I couldn't be of more help.

Thats ok I appreciate you letting me know. I talked to Mark and he suggested the KT-90's in place of the stock tubes so I ordered a quad. He matches and burns them in before shipping. My Tempest II came with 2 sets of quad EH KT-88's and I have no idea how many hours were on them or how matched they are. I have had problems with 2 tubes so I said screw it and ordered a new quad from Rogue.

Samzx12,

You're welcome. When we talked with Rogue about tubing my M-180's we were told that one of the factors influencing Rogue's decision to go to KT-90's was that they were having quality issues with the stock EH KT-88's (no quality issues with the Gold Lion KT-88's however). Your comment about having trouble with two of your tubes may be an yet another example of the quality issues they were seeing.

That's what it sounds like. Mark didn't mention it but was quick to suggest replacing the KT-88's. I think I do remember Kevin Deal talking about the KT-88's on his website.

Samzx12,

I talked with the guys at the shop yesterday regarding their opinion of the sound differences between the KT-88's and KT-90's (it also reminded me again why I went with the 88's). The comments they made were that the KT-88 is a little warmer, more delicate and three-dimensional than the KT-90. The KT-90 having more a little more slam and power.

I hope this helps answer your earlier question about the sound differences between the two tubes. As I mentioned, I didn't audition the EH KT-90 - I just went with the GL KT-88 right out of the gate and have been very happy.