Thought I'd provide an update on what I finally settled on for a pre-amp to mate with my Sig 30.2. At the advice of Dan Mason (dmason), I gave the Mapletree 2A Line SE a whirl and.......wow! No really, wow! It's a terrific pre-amp for the money. I'd put it up against many pre-amps more expensive. It's not the last word in anything , but is highly musical, adds a terrific dose of warmth in conjunction with the RWA amp, and the synergy is absolutely fantastic. And I haven't even played with tube rolling, power cords, or anything else. I'm using Philco 12SN7 tubes and a Sylvania 6xG5 (or whatever the regulator tube designation is), so there are additional benefits to be had here.
Will this pre-amp stand up to the Isabella (or other top pre-amps)? Well, probably not, but I'm in just over $600 for this pre-amp, and I can't imagine investing less than $2-3k for an improvement. As I mentioned, a good deal is probably the synergy: simple pre-amp circuit + octal tubes + RWA/T-amp = a terrific sounding recipe.
So, thanks again for your sage advice, dmason. Very much appreciated. Any folks looking for an inexpensive pre-amp partner for the Sig 30/30.2, look no further. Those that know me will know that I don't gush often or use superlatives when talking about audio equipment. I'm just really happy with the combo, especially since I've had other "impulse buys" that didn't work out nearly so well.
As a musical aside, two artists that sound great, great, great with this combo are Jenny Lewis with the Watson Twins "Rabbit Fur Coat" and anything/everything Richard Hawley has done as a solo artist. For those of you who don't know Richard Hawley, look him up, you'll be very glad you did. He's the guitarist for Blur (I think, or one of those Brit bands that all seem to sound the same -- unimpressive -- to me), but his solo work is stellar. It's a nostalgic sound that harkens back to the days of '50's-style crooners, but with a pastiche that combines other influences as well. Hawley doesn't sound like anyone else playing right now....good for him, not so good for other artists. He's a singular talent. I'm glad he has followed his own muse in addition to his other (considerable) session work.
Back to the music now. Listening to "Festival in the Desert" right now, a live document of a concert in Mali in 2003. Absolutely, positively great. No refunds given and none needed.
Best, -dB