Thoughts on the First Watt SIT Amps


Has anyone bought the First Watt SIT amp (either model)? If so, tell us your thoughts compared to previous amps you've had.
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Hi Phil,
That was an interesting and informative read(as always). Compared to your Audion SET amps(845 and 300b) would you say the SIT-1 is'more'resolved, nuance,faster and extended(Srajan found these qualities superior with the SIT-1)? Calling it the best SS amp you`ve heard is high praise.
Regards,
213cobra,

Good write-up! I couldn't agree more, that the SIT amps could uses a little more power and headroom. Did any of the SIT amps exhibit any noise or crackling sounds that you could hear through the loudspeakers?
>>...would you say the SIT-1 is'more'resolved, nuance,faster and extended<<

Audion amps, whether SET or Push-Pull have a uniquely fast and transparent aural fingerprint, so I don't hear the SIT-1 as "faster" than the amps I prefer. In fact, in some respects I'd say a conventional Pass transistor amp sounds a bit faster than does the SIT. I also don't hear it as able to reveal more nuance nor is it more resolved. As to the latter, let me say that I don't hear the Audion SET amps leaving anything out that I can otherwise hear through the SIT-1. But the presentation of resolution is asserted more by the start of the note than the finish, if you understand my meaning. The SET amps lead a little more softly and finish with more "glow" or decay. But the momentary event is fully present through either amp. Will some people *perceive* the slightly softer leading edge of SET as less resolved than the SIT solid state amp? Maybe, and I can understand why. But that's not how I would rank the two different presentations.

As for extension, in the room I listened in, with recordings I am familiar with on my own systems, I did not hear deeper bass information with the SIT-1 (nor the SIT-2) than with SET, but the definition and agility of the sub 100Hz region is superior on the SIT amp -- either one of them. I'll venture that Dominance's extra measure of dynamic ease over Definitions is also apparent in the downfiring sub, by a discernible margin. So in a larger room with much more power, that speaker can deliver bass authority that might be mistaken for more "range," but where it might dig deeper I think that's relevant on very few recordings. As for the SIT amps, I haven't heard deeper-than-SET in either case, but the SIT amps reproduce bass more precisely, which is good.

On the top end, the Radian 850 is exceedlingly resolved and smooth at the same time, but it is not a hyper-extended tweeter for the ultra-sonic obsessives. Both the Audion SET amps and the SIT amps have top end response exceeding the flat response of the tweeter. Again, the presentation of top end information is different, but the presence of it is the same. I have this debate all the time with people who believe they like p-p tube or ss amps over good SET. With the Audion amps, all the information is present on top, that you get from the SIT (either one) but the sonic profile is somewhat different.

Where things get dicey from a value standpoint is: would I choose a single-ended SIT amp with tunable bias over a very simple-circuit push-pull tube amp like a Quad II Classic or Quad II-Forty, at $3k - $4k for the tubes and $10k for the SIT monoblocks? I would definitely pick the Quads over the SIT-2. The SIT-1 is a tougher call if cost is discounted and only sound is the selector. SIT-1 has the tonal unity of SET, which even the simplest p-p can't quite duplicate, but the simple Quads do better on dynamic heft and deliver the whole note with a minimum of crossover notch grunge. Not so with more complicated and massed-push-pull mad-power tube amps. With efficient speakers, I'd take SIT-1 monoblocks over any modern overwrought push-pull tube amp featuring more than one pair of tetrode or pentode tubes per channel.

Phil
>>Did any of the SIT amps exhibit any noise or crackling sounds that you could hear through the loudspeakers? <<

Both SIT-2 and SIT-1s were dead-quiet in any practical snese, in my two encounters with them.

Phil
I heard one of the SIT amps recently, and it sounded very good, fuller and richer than other First Watt amps also demo'd.

One concern I might have is how many of these SIT devices exist. It's not the same as availability of NOS tubes.
Phil,
You have described in the past the sound of various components that I`ve also heard(ARC for one example) with dead on accuracy(I share your conclusions).I`d put much weight on your SIT-1 impressions. This appears to be an exceptional amplifier.Given your detailed comparison I imagine I`d like it quite a lot but probably not to the point of it replacing my current amplifier.Those 'special' qualities of good DHT SET amps are mandatory for my ultimate enjoyment.

Thanks for taking the time to reply with such useful insight.
Charles,
Best Regards,
From an operational standpoint, do the SIT's run hot or are they similar to Class D? While I love my tube amps, it would be nice to have a good sounding alternative that could be run during the Summer months.
The SIT-1 runs pretty hot for a solid state amp. Sort of like the old Bedini Class A amps did. SIT-2 runs quite warm too. These are definitely NOT cool-running boxes like Class D amps are. On the other hand, I don't think this is at all pertinent to season. No reason not to run the same gear year round.

Phil
Thanks much for your reply. The SIT amp sounds very intriguing. Hope to audition one in the near future.
Jon ver Halen pointed me to this. In my experience systems where this sort of noise has occurred have high impedance in the source. This is why I have the input buffer option on the SIT amps.
Brawny, you comment on bass from the SIT amp. Yet your Avant Garde speakers uses a plate amp with crossover ranging from 60-350hz. What do you mean by this? Thanks.
I am currently using a sit 2 from Nelson. It's very quiet and very dynamic. I use a tvr for pre amplification. The First few days have been very impressive. It will drive even my 89db bright stars, but shines with the triangles. For jazz I use omega 3s or the Abby's. it has a huge sound stage with well controlled bass and sweet midrange. It seems to work it all sorts of types of music so far.

This is my third amp from Nelson. I have the f5, powerful but slightly dry, the F3 smooth dynamic perfect for jazz with single source or efficient multi driver speakers.

I recommend a trial from Reno Hi Fi, talk to Mark.
I wanted to revive this thread in case anyone had recently auditioned the SIT amps with a good DHT preamp.
Haven't used it with a DHT preamp but have used it with Rogue Audio 99 Super Magnum with Mundorf Supreme Silver/Oil with psvane cv-181 and tj full music and now with a Rogue Audio 99 with the Supreme Silver/Oil Caps(with electroharmonix gold ins). I've owned the Sit-2 for about a year now and it's probably the most transparent amp I have ever owned. Quite impressive really. I can't say the amp has a particular sound in that it will just present exactly what is presented to it. So you really need to pick your front end to taste. you can make it as lush/tubey or as neutral as you want it. What it does convey is detail in spades.
cobra213 "I’m going to make it a point to hear the SIT-1 monoblocks with a DHT preamp in front of it. I have listened to DHT preamps and have heard the SIT-2, but have not heard the two sequenced together. I’ll give Srajan benefit of doubt, and I do believe the adjustable bias monoblocks will get closer to being musically convincing than the SIT-2 regardless of what’s in front of it."

"I still want to hear SIT-1s driven by a DHT preamp, to hear whether Srajan’s postulate about the leap in results is true for me. But this was one step further in gaining experience with these amps."


213cobra, much time has gone on, yet has anyone followed up on Srajan’s example? As I do not believe he would have sold off the remainder of his once treasured DHT power amps in favor of the first watt SIT-1s if not for what the compo had accomplished. 
I have to say my Firstwatt F7 sounds amazing with the Manley Shrimp preamp, into 88db Gallo 3.1s, highly recommended! Listen to Nelson's latest creation if at all possible.
Good day all,

  I have had the First Watt SIT2 since 2013. The amp gets played every day for at least 8 hours. It has been driven with an Audiopax Model 5 (the original and the latest incarnation) and a DIY White Cathode Follower OTL tube pre.

  In every case and with all music it has bested any of my previous amps to include, Mac, Quad, First Watt F1J, F2J and F4, various 300B (SET), Leben CX300XS, Yamamoto 0A-11, and 0-8s, Transcendent SE OTL, and others of lesser fare. Sometimes not by much, but always better.

  The SIT drives a pair of 15" co-axial 100dB speakers in a 15X30 living room and has had many different DAC, CD players and transports, VPI vinyl setup and separate phone pre. As the chain gets better, so does the SIT.

  Quite by accident (because I was feeling lazy) while I was changing the equipment and positions in the rack, I decided to temporarily hook my DAC (Audio GD NFB-7 2015 fed through an AP1/PP (latest edition) from a Mac Mini and JRiver) directly to the SIT using the AP1 volume dither. 

 At low to normal listening levels, I have never heard any amp, at any price present music as well as this combination. The purity is unlike anything I have ever experienced. Whatever is in front of the SIT (given synergistic speakers) is what you are going to hear. If you have a great front end and hi ef speakers, you would need to go a long way to best the SIT amps. 


I returned the SIT-2 and got back my First Watt M2 amp, which was/is really quiet. I was a little bummed-out because the SIT-2 was dead all the same when I first received it is an absolutely fantastic unique sounding amp. The First Watt M2 is really stuffy and has a couple of advantages.