NOS Tubes for Rogue Tempest II

Hey Sam - my Telefunkens 12AX7 arrived today, and I'm liking them a lot.

I've been doing a lot of rolling the past several days (both 12AU7 and 12AX7/5751), but came full circle back to the RCA Clear Top 12AU7As now paired with the Telefunkens - this is a very nice combo. Airy, spacious and more high end sparkle than the Mullards (when paired with the same 12AU7s). I think I still prefer the GE 5 star 5751s to the Telefunkens, and the Telefunkens over the Mullards, but I'm going to stick with this combo for a while.

Hey thats good to hear about the 5751's over the Telefunkens. You might think differently ;) What do you like better about the 5751's? Are they more precise, less fuzzy, and focused or do the Telefunkens have more top end energy, etc....

I got my tall bottle NOS Sylvania 6SN7 GTB in last week and have listened for about 3 hrs or so. They are much better than the stock tube thats for sure. They are very open, airy, strike a nice balance from top to bottom. I don't find any one area where they are out of balance from what I can tell so far. I wonder what I may try next. I saw some rebadged Sylvania's for Baldwin on here for cheap. I think they are black plates made in the early 60's but I have a feeling the ones I have are better.

What are you using for power tubes?

It's hard to pinpoint differences in 5751 vs. 12AX7 for me, since individual tubes in each genre sound different (like the Mullards/TFs). But I think the 5751s image a bit better for me. Like, center images like vocals are more, well, centered, and there seems to be a bit more width. Not drastic differences though.

One thing I can say though, is I tried some variations with new production tubes (JJ Ecc82 gold pin, bare bones TungSol 12AX7) and that was largely disappointing. I wanted to like something new just for $ reasons, but no dice. The Mullards with the JJs turned out "OK" - not great, not terrible - but after a while listening got boring, so I moved on...

My power tubes are stock - EH KT90s. I've never tried changing them (and there don't seem to be many kinds of KT90s out there, and I need 8 of them so that can get pricey!).

Yes I agree the power tubes can get pricy. I'll get there sooner or later and thank goodness I only use 4. It does seem from what I am reading that the 5751's are working better in most systems. I will try some those RCA cleartops before long.

I have a Rogue 99Magnum preamp and M180 monoblocks. Here's briefly my experience, and if someone wants me to expound further, please let me know.

Preamp: Looking at the front of the preamp, the two sockets on the right are the amplification pair, the two on the left are the driver pair. It is most critical to put the quietest tubes in the amplification side.

Preamp: NOS RCA 5692 in amplification sockets, Sylvania 6SN7-GTA in driver sockets. Too much sibilance for me. Moved Sylvanias to amplification sockets, 5692's to driver. Way, way, way too much sibilance for me. Sold Sylvanias to another guy in the shop who has a darker sounding system and he loves them. I went with all RCA 5692s in preamp and am very happy.

M180 monoblocks: Got the amps with Gold Lion KT-88s. Replaced the 12AU7s with RCAs. Put a Telefunken 12AX7 in and wanted to love them - they are rare and last forever! - but the RCA 5751s just sounded more pleasing to me. In terms of quietness, it was like going from ultralinear to triode all over again.

Someday I may try some Mullards in the 12AU7 position.

And please take this in the context of my system: Kimber Select interconnects, Kimber KS3035 speaker cables, Silverline SR17.5 speakers with Mundorf S/G/O capacitors (soon to be replaced with Duelund VSF caps).