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).
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).