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Reviewer: Srajan Ebaen
Financial Interests: click here
Source: 27" iMac with 3.4GHz quad-core Intel Core i7, 16GB 1.333MHz RAM, 2TB hard disc, 256GB SSD drive, ADM Radeon HD 6970M with 2GB of GDDR5 memory, PureMusic 1.89g in hybrid memory play with pre-allocated RAM and AIFF files up to 24/192; Audirvana 1.4.6 in Integer mode 1, Metrum Hex, AURALic Vega, SOtM dX-USB HD with Super-clock upgrade & mBPS-d2
Preamp/Integrated: Nagra Jazz, Esoteric C-03, Bent Audio Tap-X
Amplifier: First Watt SIT1, SIT2, F5 & M2
Speakers: Aries Cerat Gladius
Cables: Complete loom of Zu Audio Event, KingRex uCraft USB cable, Zu split USB cable, Van den Hul AES/EBU cable, Tombo Trøn S/PDIF cable
Stands: Artesania Audio Exotyeric for front end, Rajasthani hardwood rack for amps
Powerline conditioning: GigaWatt PF2 and PC3 SE Evo
Sundry accessories: Extensive use of Acoustic System Resonators, noise filters and phase inverters
Room size: 5m x 11.5m W x D, 2.6m ceiling with exposed wooden cross beams every 60cm, plaster over brick walls, suspended wood floor with Tatami-type throw rugs. The listening space opens into the second storey via a staircase and the kitchen/dining room are behind the main listening chair. The latter is thus positioned in the middle of this open floor plan without the usual nearby back wall.
Review component retail: Not available for sale but you're encouraged to build your own

22 January 2013 19:54. After Nelson Pass announced his Beast of a Thousand Jfets article, I asked him whether he knew of FAL's 60wpc SIT amplifier which contributor Frederic Beudot had pointed me at. Does a sushi chef know all his local seafood suppliers? "I know FAL very well. He was the source of my 2SK77B stash and associated small signal-level SITs all from the source which supplied Digital Do Main. I negotiated with them for over a year about buying these parts but quantity and price were too high. Later it turned out that the Tokin factory’s production line for these SITs was damaged in the Japanese earthquake. My samples now are apparently 10% of the world’s entire supply. Hence I expect limited production for his product. I nevertheless wish him well and still am planning on a small quantity of two SIT amplifiers myself, one using the complementary Sony parts and one the 2SK77B. You can be certain that you will have opportunity to play with both." But what showed up first in Villeneuve a few days prior to the Munich HighEnd 2013 was an F6.

03 May 2013 20:58. "I had a few finished pieces from the pilot run. I’m only planning on a few of these for friends and family. As much as I like the amp, my plate is too full to release it as a product. But I’m getting some interesting commentary. Apparently people like it better the second time around. The difference was that I used a detailed selection process on the output devices to get the harmonic structure I wanted without screwing around with the transformer loading." np

If you're beginning to wonder why a review of on unobtainium amp—the globe flag should have given it away—it's because it isn't unobtainium. In Nelson's Burning Amp 2012 talk which we syndicated here, he explained the F6 design and how to build your own. A DIYaudio thread already some 418 pages long when I wrote this includes extensive journeyman commentary from folks doing exactly that. With this review, I'll merely add a few more reasons why you should.


The perhaps most obvious attraction is the F6's power rating. It's 30/50wpc into 8/4Ω. Thus unlike my 10/8wpc SITs or other models in the FirstWatt catalogue, the push/pull F6 (mini transformers handle phase splitting and passive voltage gain, four SemiSouth SJEP 120R100 power Jfets cover the output stage) accommodates more conventional speakers. In that regard it's closest to the F5 which amongst DIYers is perhaps the most popular design of the whole F lot.



By way of contrast, I will be comparing the F6 as it was assembled by the famous maestro himself to his earlier F5 (now out of production), to his still current M2 (which also involves signal-path transformers for passive gain) and to his current SIT2 (again based on power Jfets like the F6, albeit in single-ended mode and of the very rare silicon-carbide 'static induction' variety). Since I've formally reviewed all of these models, readers curious about more background can reference my prior writeups for the bigger picture. Just check the archives.