Warm, yet detailed tube preamp

Yes, that looks like a very nice design, and not as expensive as I thought. Wonder what the harmonic cancellation sounds like (assuming it’s a push-pull topology). I still think the Aikido is one of the "great ideas" of audio and considering how cheaply it can be built, and how easily it can be upgraded to give stellar performance, it’s also a great bargain. ;-)

"I've never heard the Cary SLP98, but I, personally, do not consider my SLP05 to be warm."

I have a Cary SLP98 and it is warm, but also rather thick and sluggish, and was replaced by my own version of a Don Sachs-style Aikido 6SN7 preamp, which is much faster and more transparent but still rich and warm.  Unfortunately Don has stopped making his Aikido preamps, and the Tubes4HiFi SP14 it was based on is good but really a DIY project and not as refined as Don's version.  For the OP, I would look at a 6SN7-based preamp for the combination of heft, detail and complete lack of distortion that that tube exhibits.  The LTA MicroZOTL, Icon's Pure Valve, even the Black Ice Fusion.

The SLP-98 is a nice preamp, but somewhat hampered, IMO, by the simple parallel 6SN7 configuration and the stock output capacitors.  I tried many tube and cable combinations with mine and achieved decent results, but by comparison the Aikido 6SN7 is much "faster" and more transparent, offering more information and liquidity while maintaining the linearity and naturalness of the 6SN7.  Part of that is due to the noise-cancelling properties of the Aikido, as well as the SRPP-like configuration.  If you like the Cary but haven't heard an Aikido-style preamp I think you'd be surprised at the comparison.  It's too bad Don Sachs doesn't make his anymore.  An assembled and upgraded SP14 is a close contender, though.

An assembled SP14 with remote is a terrific value for under $2K, IMO.  The SP14 board is the same one Don Sachs used for years and it's very well designed, with regulated filament and high-voltage supplies.  I've also found that the specific operating points chosen for the tubes makes for a particularly good-sounding Aikido.