Reviewer: Srajan Ebaen
Financial interests: click here
Sources: 2TB iMac 27" quad-core w. 16GB RAM running OWS 10.8.2, PureMusic 2.02, Audirvana 1.5.10, Aqua Hifi La Scala II, Metrum Hex, AURALiC Vega, SOtM dX-USB HD w. super-clock upgrade & mBPS-d2s, Apple iPod Classic 160GB (AIFF), Astell& Kern AK100 modified by Red Wine Audio, Cambridge Audio iD100, Pro-Ject Dock Box S Digital, Pure i20, Nagra HD DAC with MPS [on review]
Preamplifier: Nagra Jazz, Esoteric C-03, Bent Audio Tap-X
Power & integrated amplifiers: FirstWatt S1, F6; Crayon Audio CFA-1.2; Goldmund Job 225; Gato Audio DIA-250; Aura Note Premier; Wyred4Sound mINT; AURALiC Merak [on loan]
Loudspeakers: Albedo Audio Aptica; soundkaos Wave 40; Boenicke Audio W5se; Zu Audio Submission; German Physiks HRS-120, Gallo Strada II w. TR-3D subwoofer
Cables: Complete loom of Zu Event; KingRex uArt, Zu and LightHarmonic LightSpeed double-header USB cables; Tombo Trøn S/PDIF; van den Hul AES/EBU; AudioQuest Diamond glass-fibre Toslink; Arkana Research XLR/RCA and speaker cables [on loan]
Power delivery: Vibex Granada/Alhambra on all components, GigaWatt PF-2 on amps
Equipment rack: Artesania Audio Exoteryc double-wide 3-tier with optional glass shelves, Rajasthani hardwood rack for amps
Sundry accessories: Acoustic System resonators
Room: Irregularly shaped 9.5 x 10m open floor plan with additional 2nd-floor loft; wood-paneled sloping ceiling; parquet flooring; lots of non-parallel surfaces (pictorial tour here)
Review component retail: $6'500

When asked how my review findings for his production vs. DIY FirstWatt F6 amplifiers tracked his own, Nelson Pass replied that they fleshed them out. And, "nice listening room you’ve got! For FW I am working on some new stuff, including a small version of the amps I did for the Sony commemoratives. As I will be making 11 of them, I will reserve one for you to try. Your living room reminds me of the one at Sea Ranch which is comparable in wood, space, windows and irregular shapes. It’s 2nd story to give a fine line of sight to the water. The small 'Sonys' will be push-pull followers (Common Drain operation). That is the only such case so far of VFETs (SITs) coming out of here. The big ones were designed around the Sony AR1 speakers with the intent of emphasizing the performance into that load and looking to showcase the dynamic qualities. That was an interest of the people at Sony. I think it was successful in that regard especially. And, they had the interesting character of actually having less distortion at the 4 ohm impedance than into 8 ohm loads, the first case I have observed of such a topology. The little amps should have a touch of that but with the wattages familiar to the FW crowd. Funny you mention the Digital Do Mains. I was gifted a small quantity of those 2SK77B parts from FAL in Japan and am in the process of wrapping up a 40 to 50-watt single-ended design using them in a new smaller PL type chassis although there is not a possibility of actual production. I am told that the fabrication line at Tokin was damaged in the Japanese quake and they are not electing to rebuild it. So it looks like we are once again dealing with NOS parts. I managed to get thousands of the other examples but for the 2SK77B we will be lucky to see 20 channels.

"Joe and Desmond have finally convinced me to adopt a pair of the Tannoy 15” HPD coaxials that Joe has been working on for the last 10 years. Hearing the latest iteration in Jensen Imperial enclosures a month ago convinced me that it was time. A pair now reside in my small working sound room. With some correction on the bottom for room modes, they sound pretty spectacular. With a little more work they will, I think, be perfect for comparing little and bigger amplifiers. Already it has become easier to hear the differences. They have articulation and dynamics beyond my previous references and measure flat too. The  most critical listener I know is Joe Sammut. The Tannoys have held his attention for 10 years so of course they would be good candidates. Part of it is the desire to be able to put our critical listeners on the same page. At the same time it is important to have some variety. For that I maintain two other installations, one of which has remained fixed for 4 years and the other runs with whatever happens to be getting worked on or is passing through.The very fact that one speaker with good tonal balance can allow you to make out lyrics or isolate small sounds that another equally balanced speaker does not is a strong clue. Of course, that trick usually only works 'the first time'. You will tend to hear the phenomenon in both speakers thereafter."

When I injected how this was quite the endorsement for Tannoy; and a reminder that 'vintage' audio had already gotten many things right which a lot of modern stuff still struggles with - Nelson had this: "I had never given the Tannoys any attention until Joe started using them exclusively. His system still had too much bottom end for me but his latest iteration fixed that (except for room modes, a separate issue). I ran across a diyaudio thread about coaxial horn throat transition. Mentioning Tannoys in this regard got a large response so I guess this is not much of a secret. That said, Joe has been working the crossover forever and they do measure very well. I think the difference between then and now is that in the old days, they had to put much more emphasis on listening. When the cone equals rigid-piston model became popular with the availability of higher-power amplifiers, the art became less subtle." About using a listening panel vs. a lone-wolf decider, "agreed. I prototype the FW stuff in pilot runs of several units and pass them around. Not only does it give me more ears on the ground, I get to see how sensitive a design is to variations in parts and such that we would see in production. But then I have a manufacturer’s mentality. Never build just one of anything."

Now our email ping-pong would switch tables. That's because I asked Nelson whether he had any models in the Pass Labs catalogue which sonically overlap with FirstWatt. "Not really. While we use the results of FW experiments to inform product design in PL, I deliberately put some distance between the two sets of product. Obviously, PL product is geared more toward the mainstream. It has the hardware to deliver more power and control into tougher loads. Since the introduction of the XA.5 product, all the amps have used a 3-stage complementary push-pull topology with a cascoded Jfet input stage, Common-Source Mosfet 2nd stage and Common-Drain Mosfet outputs. Besides heavy Class A operation, one of the things that differentiates PL from other offerings is the use of high-current single-ended constant current sources (CCS) in the output stage. This helps bias the output stage, which improves the sound at lower power levels. That helps us define the specific characteristic of the sound. If you are interested in exploring the relative differences and overlap, you would probably want the XA30.8. I certainly can arrange for one if you like."

Whoa. Nelson had just served me a sliced curve ball. After having explored nearly every one of his FirstWatt models over the years, this would be my first exposure to the grown-up stuff of Pass Labs. When I say grown up, keep in mind that I'm a babe in the loudness woods. I consider 90dB peaks in the seat plenty loud. My median listening levels tend to hover around 70dB. This leaves plenty of dynamic headroom where recorded. Then consider how I favour and now finally only own simple two-way speakers possibly augmented below 40-something cycles by a sealed self-powered infrasub. Anything beyond a small Pass Labs amp would be wasted on me. Not that such an assessment buys one much reprieve from seriousness in this catalogue. Though a mere 1/6th the power rating of the Point.8 range's biggest, the 30-watt stereo amp still draws precisely half its idle power. That is—hold on tight, Green Peaceniks—375 watts! That's certified true Class A bias, not fast and loose marketing copy for some pseudo Class A scheme.

The 30.8 tops out at 40 volts and 20 amperes and like all the other XA models, produces 26dB of voltage gain. In use it steams up to 53° Celsius, books a slew rate of 50V/µS, cuts output noise to 30-50uV* unweighted and DC offset to 0.05V. At a studly ship weight of 106lbs, it's got 60%+ of the XA200.8's back-pulling impact. On bandwidth, it promises 1.5Hz - 100kHz. And whilst we're on power speculosity, John Atkinson, for his Stereophile review of the 60-watt monos of the previous Point.5 incarnation, found that though "specified as putting out 60W into 8Ω (17.8dBW), the XA60.5 considerably exceeded that power, delivering, at 1% THD, 130W into 8Ω (21.1dBW), 210W into 4Ω (20.2dBW), and 330W into 2Ω (19.2dBW)." Though clearly the baby of the Point.8 range, my 30wpc loaner would be no descendant of dwarves. No, it'd be a strapping lad. Or mo ghille mór foghain'each as my Scottish ancestors would have said in the Gaelic. On a forum, I found Pass Labs' own man Desmond quoted as saying that "the XA30.8 will output 90 watts @ 1% into 8Ω and almost 150 watts @ 1% into 4Ω." In short, the paper ratings here are arch conservative. Bragging is left to the other guys (and valve SETs which specify power with a 5% THD tolerance).

* "These noise improvements have been partly a result of the FirstWatt work. 20 years ago, our products spec'd out at 700uV noise performance. - np"