SET amp comparable to First Watt SIT 1?

You may see what Volti Audio has to say. I have listed the owners contact info below; also there web site has a dialogue box for contacting them.
It also seems helpful to use this platform to reach out to others that own your Brand/model of speaker (Need Help From Volti Users) and ask them what they have tried with there speakers and what and why they selected there amp/integrated of choice.

By the way Volti Audio used a BorderPatrol S20 single-ended 300B amp the RMAF in 2012

CONTACT
voltiaudio@gmail.com
Greg Roberts
Volti Audio
6100 Nashville Highway
Baxter, TN 38544

Tmare,
I fully understand your predicament in trying to narrow down the field of worthy amplifiers. It is frustrating in the sense that it is not really  realistic to be able to hear these various 300b SET ampliifiers and particularly in your own system. It is by nature very subjective (just look at the responses thus far) and all of us have our own bias and preferences.

Then there’s the question of what is 300b sound? You can generalize in only a broad and somewhat vague sense as different 300b amplifiers have their own sound. Circuit, part quality, transformers and power supply are significant factors of sonic influence. Then factor in the variable of different brands of the 300b tube itself.

Even the same country of origin there’s ample variety. Japan for instance offers many choices, each with its own musical character. Some offer more grunt and drive than others,some more warmth, others more neutral and transparent. You get the point I’m sure.

Volti has mated with the Border Patrol at a number of shows, that list I posted yesterday consists of high quality alternatives. Tmare I don’t blame you for wanting to experience a 300b SET amplifier. A good one has the capacity to thoroughly connect you on a deep emotional level with your music.
Charles

I really appreciate the suggestions that I find them very helpful. I put the Border Patrol at the top of the list. I just read 6 moons review about their SE 300B. Should be an excellent amp.

If the Volti model you are buying is the Vittora, you may be able to use a lower power SET amp using a 2A3 or 45, which opens the door to lots of options other than the 300B.  I have heard the Vittora at several of the Capital Audio Fest shows, and the very best sound in my opinion was with Greg Roberts' own 2A3 SET amps.  At one of the shows, when a room visitor asked Greg to play a particular CD he turned the volume up and said he would have to switch amps because he could hear some compression on peaks.  He then hooked up a borrowed pair of Border Patrol 300B amps with 18 watts.  For what it's worth, I didn't hear the compression with the 2A3 amps and this was a very loud volume, louder than I would normally find comfortable.  Also, to my ears the Vittoras did not have the same magical sound with the BP amps that they had with the 2A3 amps.  This wasn't just due to the BP amps being cold when I first heard them; Greg left the BP amps running for the remainder of the day so I had a chance to hear them after they were fully warmed up as well.  I am not saying this to put down the BP amps but rather to emphasize that for many listeners, such as myself, the 2A3 amps would have had plenty of power on the Vittoras.

Sal is right in that the very high sensitivity of the Volti Vittoria makes all of the low power DHT tubes viable options. The problem is which one? There are countless threads on numerous audio forums regarding this genre of tubes,. Everyone has their favorite, some say that the 45 is better than both the 2A3 and 300b,. Others insist the rarer 50 is superior, another person would be an advocate for the PX 25, it never ends. You could spend half a lifetime sampling the vast world of SET amplifiers given the plethora of choices in the marketplace.

Say that an 2A3 SET were chosen, which particular one? They all do not sound the same. Tmare has specifically on two occasions expressed a desire to go with the 300b. I would try to hear the Border Patrol (top of his own current list) and use that SET amplifier as a point of reference and go from there.  Honestly any of the DHT  tubes mentioned above in the hands of a talented builder and high level implementation will yield an excellent SET amplifier. 
Good luck,
Charles