Nelson Pass First Watt amp F1

Any experience with this amp? I am VERY seriously considering getting one, but would like some feedback from the folks at the 'gon first.
I heard one at the T.H.E. Show a couple of weeks ago, in a room with Lowther Academy speakers, run with an analog(VPI) front end.

Frankly, I wasn't impressed, and apparently neither was the exhibitor, because the next time I went back into the room, it was gone, and replaced with an Exemplar Audio 300B amp. This 300B amp sounded quite a bit better than the Pass First Watt amp did.

I know that the show environment is not the best way to listen to the true performance of many things, but in this case it was easy to spot the difference of the amp when it was switched out to a 300B amp, and the rest of the system remained the same. Not even close.
From reading the 6moons review of the F1 I sense it has to be very carefully matched to the other components. Within a well matched range it supposedly is spectacular, outside that and it doesn't work. I'd start there and of course email Pass about it.
Interesting insight so far, not as promising as I had thought it might have been. I am thinking of using it in my current system(emm labs front end, vonschweikert db99's and jena labs cabling) any thoughts? I have contacted first watt(which is seperate from pass) and they have been a great help so far, but I am curious about what consumers think.
It is not compatible with multiple driver speakers unless the crossover is designed to be driven by a transconductance amolifier.
This is a very specialized amp that boasts an 80 ohm output impedance. In effect, the amp is designed to be "loaded down" by the loudspeakers, which results in a shifted tonal balance. This shift in tonal balance helps to compensate for the lack of low frequency weight found in many "full range" aka Lowther, Fostex, etc... type drivers. If used in conjunction with more conventional multi-way loudspeaker designs, it probably won't sound too good. On top of that, and as Herman pointed out in another thread, the crossover points on the loudspeaker will be altered. Due to the fact that this amp acts like a current source rather than the more conventional and commonly used voltage source designs, it will have very limited mareketability and would be "near useless" for most audiophile type speakers. Sean
Interesting design!

If it is a current source, rather than a voltage source, perhaps some Apogee users might find a good amplifier there. Maybe it won't melt like most amplifiers out there.

Conversely, most more "traditional" speakers might sound odd when paired with it.

How much does it cost???
Well I guess that answers my question, not the amp for me. I guess I'll just stick with tubes, its working for me, my mind just runs crazy from time to time.
Hey Twl, from looking at this article it appears that a frequency shaping network is required to optimize the performance of a particular driver with this amp. If the ones you heard at the show did not have one (my guess is it did not) then that may have contributed to your unfavorable impressions. I've never heard this amp and probably never will but it is an interesting concept.
I dunno.

The guy told me that he got it from Nelson, and I would have expected that everything needed would have been with it.

The exhibit was from the maker of the speaker system, so I don't think that anything would have been left out internally, or externally, because he was making the stuff, and he sounded from his conversation to know Nelson Pass.

But, to answer your question directly, I don't know for sure if there was any network used or not.

There is some in depth discussion and very favorable results described at the horneshoppe website. They are of course using it with the single driver horn shoppe horns, but seem like the amp was a revalation to those speakers.
Tim, thank you for the information!

I don't think you are a good candidate for the amp, with your VR DB99 loudspeakers. I would be more than interested to hear if anyone with a brutally difficult loudspeaker load, such as the just about dead short Apogees, have had success with the amp, as the impedance would probably pose no problem it.

Maybe I am all wrong guys???
Trelja, since it is rated 10 watts per channel, I think it is limited to higher efficiency designs.
Twl, like most of us, you are coming from a voltage source mindset. Just about all of us think in this manner. That is the way of audio. A current source is a WHOLE different ballgame.

I have heard stories of people building low watt amplifiers that were operating as current sources, and they drove the absolute devil out of their earlier Apogees (virtually almost dead shorts). Conversely, even some absolute beasts of more traditional amplifiers (the bigger Krells, MLs, etc.) literally blow up or melt with the same loudspeaker.

Perhaps Sean can educate us a bit on the differences...
It was a tough room and the Exemplar 300Bs are in a different class than the First Watt ($8k vs $2500). I think a much more accurate listening session could be arranged in a bit larger room. The thing about the Academy speaker is that it begs for a larger room to really open up. When in a show environment with a very
limited room, they pretty much need to be played at levels that are sitting room polite. To let them strut their stuff and impress, a lot bigger space is required.
Thanks for stopping by.
Yes, that was the room.
I have to say that I was just referring to the amp comparison in my previous post, and the speakers were an excellent iteration of the Lowther Academy design.
Extremely good construction quality, and beautifully finished.
I'd highly recommend those to anyone interested in one of the classic Lowther designs.
Vivaldi Audio,

Please clarify if you optimized your speakers with frequency shaping networks designed to work with the First Watt. These networks seems to me to be a key component to getting good performance from a transconductance amp.

Actually Nelson Pass optimized the Speaker for the amp. Again, I would comment that a 10 minute listening session
in a show room really isn't a great indicator of much of anything.