5751 tubes and Rogue Tempest?

Have the KT90s in my Cronus Magnum, and the GL KT88s in my Ayon Spirit 2 and agree about the sound as Reynolds853 described.

Use Tungsol 5751s in the Cronus, added some warmth

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.

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,

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.

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,

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.

Reynolds853...How did the GL 88's improve your system over the stock tubes? Were your stock tubes EH KT-90's?

As I posted in more length in a similar thread, I preferred the RCA 5751 over the Telefunken 12AX7. The Telefunken was more dynamic, I guess, but 5751 seemed to give me a sweeter sounding system. But it wasn't so much the dynamics but rather the musicality and reduced noise that the 5751 gave. I describe it as like going from ultralinear to triode all over again. But whatever the actual proper way to describe it, I just preferred the 5751 and am happy with the dynamics of my system. And my system is plenty dynamic.

System:

Rogue M-180 monoblocks with RCA 5751, RCA 12AU7, Gold Lion KT88

Rogue 99 Magnum preamp with RCA 5692

Kimber KS-3035 speaker cables; Kimber select interconnects throughout

Silverline Bolero speakers

The system sounds fine to me.

Caveat: the bottom line is that you need to try a couple of the tubes you are considering and see how they sound in your system. What worked for me may not work for you.

I think the 5751's sound much better and have a LOT more focus than the 12AX7's. The 12AX7's sound fuzzy in comparison. Have not tried a 12BZ7.

12BZ7 is the ticket. Much better dynamic contrast and safe to substitute for the 12AX7 according to Rogue.

I initially swapped out the stock 12ax7 for a telefunken 12ax7 in my M-120 monos. Then went to the RCA command series 5751. The 5751 is a keeper.

Yes I have.If you like your sound a little more laid back it is very nice.
I switch back and forth all the time.
Make sure you get good NOS 5751.