SET amp comparable to First Watt SIT 1?

I agree with Charles and the other comments. My recommendation about Border Patrol was three-fold: (1) it is made in Maryland and therefore repairs are easy (my recent experience with my Ancient Audio taught me that lesson, but that is another story), (2) Gary Dewes makes only 300b amps (SET, PSET, and PP), and (3) he occasionally sells pre-owned and he might be persuaded to let you have an in-home audition. Compared to the 45 and 2a3 SET amps that I tried, I found my 300b amp to be more dependent on the specific 300b tube that is used. Takatsuki trumped Sophia RP (by a lot) that trumped Shuguang BT (also by a lot), etc.

Per atmaspere's comments- I run 95-96dB open baffle speakers in a moderate size room (14'x23'x8.5') and acoustic/american/fold/country music and found that it was very easy to drive a 7-8w 300b SET or a 10-11w EL-34 SET into that higher distortion zone that he talks about, if I ran the volume up to more than moderate levels.  If your room is not too big and you don't listen very loud, you MIGHT be OK  w a 300b.  If you are a classical music listener, the wider dynamic range will definitely run a 300b amp into clipping.  I switched to a 30 wpc OTL amp and the improvement was dramatic.  OTOH, if you want to give the SET route a try, drop me a p.m.  I have a very good one that is looking for a new home. 

Tmare,
If at all possible I'd strongly urge you to directly compare a high quality 300b SET to an Atma-sphere amplifier and judge for yourself.  I've done this myself. Both amplifiers were very good but certainly  with different presentations. I preferred the 300b SET sound and the obvious point is opinions/preferences will of course vary.

I believe that either choice has excellent potential with your Volti speakers.
Charles

In Linear Tube Audio amps sounded very good to me at Capital Audiofest this past summer for very reasonable cost.  These use some proprietary output transformer magic  (David BEerning ZOTL technology)  in place of a traditional output transformer.    Models I see range from just a few to 40 or so watts per channel.



 

I've heard a David Berning amplifier but not the Linear Tube Audio amplifiers. I believe that they utilize a high radio  frequency transformer in place of a traditional output transformer. These are more reasonably priced than the David Berning line. 

There are many good lower power amplifiers to choose from when you have a high sensitivity/efficient speaker such as the Volti. 
Charles