SET amp comparable to First Watt SIT 1?

You can also get a Wyetech Labs SET Sapphire 300B monoblocks with plenty of power to drive your speakers [ 18 watts RMS ] It's also on sale now at $7800 a pair

Thank you so much for the precious comments again.

Regarding the rooms size, my rooms size is 15ft x 30ft, ceiling is 8-10 ft (room is a bit irregular), and listening position is about 10-12 ft (3m) from the speakers. I mostly listen to jazz, classical (piano, chamber) and vocal. I usually do not listen to orchestral or rock, but I’m afraid that my current normal listening level would probably be a bit louder than the other SET people, considering the level that the SET exhibitors play at the audio show. It is definitely louder than Audio Note demos, but not loud as those loud solid state demo rooms. I start wondering if 300B SET is really powerful enough for my propose, since several people mentioned it... I also wonder if 100dB or 105dB speakers make a big difference.

Hi tmare,
You have a generous size listening room. You’re beginning to express some concerns. Why don’t you call Volti and talk with the builder himself? Parallel SET 300b, 845 or 211 SETs are options. Ask the builder his thoughts regarding OTL amplifiers as well. Discussion with him is a good starting point in my opinion.  Man oh man,  you have wonderful options. 
Charles

Hi Charles, thank you for another great advice. I really wanted to try 300B SET, so I know I should just go for it, at least for my first SET amp.

The reason why I have not contacted any manufactures on the list is I feel my candidates should be narrowed, and I don’t want to bother those people with my ignorant questions, also I don’t want to be biased by them. I’m planning to contact all manufactures when my candidates are finalized. and I’ll do it very soon. I have learned a lot from this thread already, and I’m much more confident what I was trying to do!

tmare,

PSET (Parallel Single-Ended Triode) topology with 300B tubes will do fine at the Volti- efficiency level, your listening habits and your room size. On nominal 100db/w/m speakers using for example 24w Audion PSET 300B Golden Dreams, at 1m you'll yield 112db at the 16th watt, and be quite usable into soft clipping by 115db. Now, you'll be sitting 3m away, and room surfaces, contents, etc. will reduce those actual and apparent levels at your listening position. If you routinely listened to full orchestral music at symphony hall crescendo live levels, you'd probably want a little more dynamic headroom in that listening space. But what you outlined indicates PSET 300B will be more than sufficient on a ~100db/w/m speaker.

You can drive keep most aspects of the 300B SET sound with a push-pull configuration. You'll gain some bass discipline but lose some nuance and tonal purity. Still good. But unless you find a four-tubes/ch p-p amp, the actual dynamic gain over PSET will be only about 3db.

A ~24w 845 SET amp will have the same measurable dynamics but will sound subjectively as having more "shove." For your stated preferences, I don't think the trade-off of 845 SET muscle for 300B PSET nuance and transparency is necessary.

For reference, on one of my systems, I use 24w on 101db/w/m speakers in a 21x14x 8.5 room, unbounded in two walls so he acoustic pressure dissipates into an open plan house. Seating position is 11.5' from the centerpoint between speakers.  I can cave my skull in with full on rock or symphonic music. You'll do fine.

I suggest against 211 amps. Tube choices are narrower, and you don't get the 845's shove nor the 300Bs nuance, tone and delicacy.

Phil