SACD, SETs, Lowthers, and Other Life Forms: In Which PF Takes A Magical Mystery Tour!
David W. Robinson

With A Little Help From My Friends…

SETs. Lowthers. SACD. And yours truly. How did I get involved in a project like this one? Where to begin to tell the story?

It was inevitable, I suppose. Sooner or later, it had to happen — given all the good friends and acquaintances who were so taken with low powered Single-Ended Triodes — and I would spend some time with this approach to audio. This would mean finding some of the top flea-powered designs, and mating them with a loudspeaker that could deliver reasonable volume with low powered input. (As Scott Frankland pointed out so elegantly in a previous issue of Positive Feedback, low powered SETs require special care and planning — the amplifier/speaker interface is of critical importance. An improper combination will lead to a truly mediocre result. Once again, synergy is the thing!)

In so doing, I would have to put aside some strong preferences. I have freely confessed it before, and will say it again: my taste normally runs to full-range, high-powered audio systems. The foundation should be at least 25 Hz, and lower is better. (My trusty TDL Reference Standards can hit 16 Hz without a tail wind; my current speakers, the wonderful Nova Renditions reach 25 Hz very handily.) The mid-range needs to be clear and well textured; higher frequencies ought to be 20 kHz – 25 kHz, and (especially with LPs and SACDs) higher is much better.

Clearly then, experimenting with this sort of audio system was going to require of me what writers and filmmakers call a "willing suspension of disbelief." I would have to knowingly enter in, and be open to any virtues that I found. I would also have to refuse the temptation to reject the approach out-of-hand, simply because it might be so different from what I prefer. This is a greater stumbling block than you might think — at least, so it seems to me. I have occasionally wondered how some audio reviewers can move so blithely from one end of the audio spectrum to the other, at rather high rates of speed, without experiencing some form of audio vertigo.

I had good audio friends and acquaintances that could help me with this project. I had known some for years; others I had met at Dan Schmalle’s VSAC ’98, written up in PF Vol. 7, No. 6. Nevertheless, not being an SET aficionado, consultation was in order. My chief un-indicted co-conspirator was none other than my friend Tony Glynn, of Lowther America. Tony and I have known each other since the days of the Oregon Triode Society, he lives less than an hour away, and he has a number of contacts in the world of low-powered SETs. Tony agreed to contact several other key SET designers:

Ron Welborne of Welborne Labs, designer and manufacturer of kits and finished amps/preamps for the SET enthusiast. Ron’s located in Colorado, and has had his products reviewed by Jeff Silverstein in past issues of PF.

George Wright of Wright Audio, designer and builder of SET preamps and amps. George is headquartered in Washington state; his products, well known nationally, have never been reviewed by PF. Until now.

Don Garber of Fi Audio, a New York designer known to the SET underground for a number of years. Don’s monoblocks had impressed PF’s Ian Joel years ago, and were favorably commented on by Lynn Olson, as well.

All three were good guys, willing to send monoblock amplifiers tubed with the well-regarded (hell, nearly legendary!) 2A3, which is Tony’s recommended glass of choice for the PM2A’s. Don would send his 2A3 mono’s (amp only); Ron his Reveille preamplifier and Moondog 2A3 mono’s; George his WLA12 preamplifier and WPA 3.5 2A3 mono’s.

Tony was willing to arrange to have Art Dudley, ye honcho of Listener magazine, send along the Lowther PM2A drivers in the Medallion cabinet that he had been working on for a project for Listener. Jennifer Crock volunteered to re-cable the Dudley build with JENA Labs cable and speaker jacks, thus bringing the cabinet up to the specification that I had heard at VSAC in the fall of 1998. My good friend Alan Kafton of Audio Excellence AZ sent over a complete set of Sahuaro Audio power cord systems that proved to be of crucial help during this project. The estimable Andy Bartha of Bartha Audio sent along two sets of his Whatchamacallits, a truly unique isolation device that had been in use at VSAC 98.

To add more interest to the project, audio amigo Dan Meinwald of E.A.R. USA kindly said that he would send one of Tim deParavicini’s V20 amps, which with a slug o’ tubes at 24 Watts per channel should not overmatch the Lowthers. Also (patiently!) waiting in the wings was the 47 Laboratory Gaincard amplifier, sent in by Yoshi Segoshi of Sakura Systems. The Gaincard is a very well regarded solid-state purist approach with about 25 Watts per channel, and would present a different synergy with SACD and the Lowthers.

OK, all was set. I would essay the task.

The High-Efficiency Speaker Question

Anyone who’s spent time in the world of low-power SETs will tell you that the biggest problem that you have to solve is which speaker to use. Unlike the realm of higher power/current designs, which can more safely ignore the amp/speaker interface, and where there are a number of fine loudspeakers which will mate well, 2A3’s are extremely sensitive to what’s downstream.

This isn’t surprising. When you’re only running 3-5 Watts (depending on the tube), EVERYTHING MATTERS. (On the other hand, I think it was Herb Reichert who used to observe that low-powered SETs "own the first Watt!")

SETs in this power category are looking for speakers that are as close as possible to 100 dB/Watt/meter in efficiency — and more is better. To observe that "this narrows the field some" is to be guilty of massive understatement. More accurate would be to say, "there’s damn few," and leave it at that. Horns, some high efficiency dynamics (like the Lowthers)… that’s it. And many of these are DIY/home-brews, which is poetically fitting — the same impulse is what drives many SET owners to build their own amps and preamps, too.

The key problem is simple: it’s hard to get deep bass and a sense of power with 2A3s. Their midrange is delicious — that’s at the heart of the SET mystique — but the foundation is not as profound as a bass lover like myself would like to hear. Furthermore, dynamics can be compressed during fortissimos, and the higher frequencies can sound a bit rolled off. To get around this, many of the speaker designs are quite ornate: external crossovers with subwoofers; massive bass horns standing many feet tall (or deep, if they’re buried in the basement!); unusual cabinets with arrays of dynamic drivers, structured for maximum efficiency (cf., "Doc B.’s World of Valve: The Slim" in Positive Feedback, Vol. 8, No. 3); stacks of amplifiers (often of dissimilar design) on an external crossover to increase the power feed to the transducer(s).

All of these approaches are an implicit confession of the weakness of flea-powered SETs. There isn’t a lot of "there" there; you have to make absolutely the most of what is offered. This does not mean that you can’t have good sound; it does mean that you’re going to have to work harder to get it, and will have to pay attention to every detail.

Choosing the Lowthers as the solution for this project wasn’t hard. I had heard them at VSAC ’98, and had been impressed by their musicality. Their high efficiency (97dB/Watt/meter), single point source design ought to mate very nicely with the 2A3s. In working with the Lowther PM2A’s in a Medallion II cabinet, I was making the decision to see what a simple, reasonably affordable, and very coherent speaker system would do. With Jennifer Crock’s JENA Labs wiring update, I would have a speaker that was a match of the VSAC ’98 system that had made such fine music at the time.

The Question of Sources: Enter SACD!

It was never in doubt that LPs would be involved in this project. Classic analog, after all, was a natural mate for SETs and the Lowthers, and my love for great vinyl is life-long. The Linn LP-12/Arkiv/Ekos/Lingo/Cirkus/Linto on the Vibraplane isolation platform would handle the vinyl sources.

Digital sources have traditionally been more problematic. Fortunately, the superb Linn CD-12 would handle standard 44.1 kHz/16-bit PCM (see my review in PF Vol. 8, No. 3) and HDCD™ discs.

The real breakthrough, though, was the fact that, while awaiting the arrival of all the parts and pieces, the Sony SCD-1 SACD player arrived. (Cf. my review notes in PF Vol. 8, No. 3). This new digital standard — which sounds like analog, without the problems that analog has traditionally been the victim of — is the massive revolutionary breakthrough that audiophiles have been waiting decades for. I liked the SCD-1 so much that I bought one for myself. Since I had my SCD-1 right in the listening room, it was an absolute no-brainer to include the SCD-1 in this project. Indeed, it was irresistible.

But would it work? Would the high bandwidth requirements (even at the "standard" position cutoff of 50kHz on the SCD-1) of the SACD format prove to be too much for SETs? Mindful of Sony’s warnings on the subject, and concerned about stability and the possibility of amplifier oscillation, I kept the SCD-1 at the 50kHz cutoff position. And I kept the volume low in my initial experiments, proceeding gingerly to avoid having to explain a disaster to some anguished designer.

I needn’t have worried. All of the equipment tested — SET and not, as it turned out — demonstrated no difficulties handling the higher level of signal source. The SETs were stable. And with SACD in place, the qualitative improvement in their performance was breathtaking. SETs flourish with SACD; there’s simply no doubt about it.

As a matter of fact, the results of this pairing forced me to re-cast my concept; no longer was it to be an SET review only… now it would be "SETs and SACD!"

The Lowthers Arrive (Finally!)…

"Ask Anything of Me but Time." — Napoleon

Once the arrangements had been made, it took far more time to get the work rolling than any of us had anticipated. It took months for the speakers to arrive from Dudleyland. During that time, various components arrived… and waited. 47 Laboratory, the V20, then Don Garber’s Fi amps arrived… still no speakers. It was more than a bit embarrassing. I remained busy with other projects, but became more and more concerned as time went by. Phone calls went back and forth from Tony Glynn to Art Dudley; time passed. Finally Art was able to get the coffins out the door.

Once the Lowthers got here, there were further delays in getting Jennifer, Tony and I together at the same time of an evening to do the JENA Labs mods to the speakers under the watchful eye of Maestro Glynn. Weeks slipped by; it wasn’t until September that the opportunity arrived for getting this phase of the work done.

Tony arrived first in the late afternoon, with some 15 Ohm (which should make Gizmo happy!) PM2A drivers in hand; Jennifer and Michael Crock got here in the early evening with power drill, glue gun, and cable a-streaming. First things first! Tony and I popped the cork on some fine Lagavulin single-malt whiskey, and toasted each other for surviving the project thus far. (Let it never be said that Ye Olde Editor did not know how to properly launch a vessel!) We discussed Tony’s views on the virtues of single-ended flea power — a subject on which he is prepared to speak at the drop of a hat — and the strengths of the Lowther PM2A with its massive and beautiful Alnico magnet (which would make the Gizmo even happier!), while watching the sun go down over Portland.

It is an interesting speaker; a single driver layout of some 22-23 cm in diameter does the whole deed. No multi-driver arrays with their crossovers; no integration of subwoofers or horns. A simple design, with a HUGE alnico magnet (2.1 Tesla flux density). The idea seems to be to get the greatest coherence by using a massive magnetic field on a high-compliance cone. The result should be speed, clarity, and precision in musical reproduction — we would see about that.

Once Jennifer and Michael arrived, it was out to the garage for a speaker modding session. We hoisted the Medallions with their folded horn design out of their shipping crates, and stepped out of the way while Jennifer went to work. She expertly pulled the old cable and connectors out of the cabinets, and then drilled extra access holes to pull her thicker JENA Labs cable through. Internal connections were made with the PM2A’s, which were then carefully mounted. The new connectors were placed in their inserts in the back of the speakers, and were screwed down.

All of this was done while Tony, Michael and I stayed pretty much out of the way. Kudos to Jennifer for ignoring any armchair quarterbacking and backseat driving that went on. Only occasionally did she mutter something about "damned amateurs!"

Tony would flick some grief her way — "David, don’t you go letting Jennifer tweak my speakers! I told her to stay away from the speakers!"

"Aw, Tony, I’m not going to touch the speakers! Just because I could make ‘em better doesn’t mean… "

"David, don’t let her touch these goddamned speakers!!"

(And lots more. Ain’t high-end audio buddies grand?!)

At last the job was done. Tony and I carried the speakers to the listening room, which is a hellacious task for old guys like us. Which leads in turn to a funny story. Before leaving, he wanted to be sure that the new cable upgrade was working properly.

"Jeez, David, I’d sure hate to get down the road and hear that there’s a problem. Is there any way that we could test ‘em quickly, and make sure that all’s well? It would only take a second."

The only amp pair that was in place and ready to go that instant were the marvelous Linn Klimax. Beautiful, glorious sound… and a rousing 150 Watts or so per channel at 15 Ohms! (And 300 Watts at 8 Ohms. And 500 Watts at 4 Ohms.) I looked at Tony — Tony looked at me — then he said, "Oh, what the hell! Just keep the volume WAY DOWN!"

Which I did.

(For the curious: just chop your volume to 40-50% of normal! Do not make a mistake!)

The Lowthers were working. ("Of course!" Jennifer would say.) We actually sat there listening for a while to the utterly insane tandem of the Linn 5103 preamp, a pair of Linn Klimax monoblocks, and the Lowther PM2A’s. For all I know, Tony and I may be the only people on the planet who’ve ever done such a lunatic thing. One would really hate to have to pull the drivers out of the wall in the event of an accident…

"You know," said Tony, "that sand amp sounds pretty damned good on the Lowthers! I might have to change my opinion about what sand amps can do."

(He was right; the combo sounded great. But somehow I don’t reckon that we’re going to see an audiophile stampede to pair Lowthers and Linn… )

Now that the Lowthers tested OK, Tony went ahead and called Ron Welborne and George Wright, to hurry them along the arrival of the rest of the gear.

We were ready for 2A3’s, and rolling at last!

Speaker Placement

While the PM2A’s are nominally rated at 30Hz-22kHz, my previous listening had indicated that the lower and upper ends of that specification were fairly optimistic. In practice, the Lowthers roll off the bottom octave to an octave and a half, so figure that you’ll start to lose the bass, folded horn and all, somewhere between 40Hz and 60Hz.

This meant that I looked for some good boundary reinforcement by placing the Lowthers a bit closer to the side and back walls. Simple experimentation led to a placement of 19" from the back wall and 22" from the side walls. This allowed for a reasonable boost in the bass response, while avoiding boominess. The width of the listening room (12.5 feet) allowed a wide soundstage; only the lightest of toe-ins (a few degrees) was required to snap in the center fill at the listening position, some 9 feet away.

The result was a bass response I would estimate at 40-45Hz; very respectable with a single driver of this size. High frequency extension was a bit rolled off, but the result was extremely musical, and never tiring.

I should note two points of interest: first, the Lowthers are made to listen to with their grill covers in place. Tony discouraged their removal, due to the fact that the powerful magnetic field of the drivers would attract dust. Removal of the covers would undoubtedly open up the high end response at the listening position, but I would hate to try and remove debris from these lovely PM2A’s. I would agree with Tony — be cautious about removing the grills.

Second, the Medallion II’s do have an opening for sand-loading the cabinet, to increase its mass. Jennifer favored doing so, but Tony adamantly opposed the idea. It seems that overdoing the sand-loading can deaden the sound of the speakers, and removing the sand is a long and messy job.

"Take my word for it, David — you don’t want to load these cabinets with sand! I’ve had some customers try it, then bitch about having to unload it. Frankly, I think they sound better without the sand. And don’t let Jennifer load ‘em with sand, either!"

OK, Tony!

My notes on the sound of the Lowthers will be integrated into each subsection following.

The Life So Short, The Combinations So Long…

The presence of the Lowthers made for some interesting possibilities! Before we got into the 2A3 flea-powered stuff, most of whom hadn’t arrived yet, we would try the Lowthers with a couple of heavier weight contenders: The E.A.R. V20 and the 47 Laboratories Gaincard. Both were rated in the 24-25WPC range, but there all similarities ended. These are radically different examples of the audio arts… different from each other, and different from just about anything else on the planet!

Out of curiosity, I had tried to drive the big Nova Renditions with the V20. No go, amigo! Polite, distant… underpowered! So to the Lowthers we went…

I. Tim deParavicin’s E.A.R. V20 integrated

By now there were some time constraints. Both Dan Meinwald of E.A.R. and Yoshi Segoshi of Sakura Systems/47 Laboratory had been patiently waiting for a response. The V20 amplifier was due back to Dan Meinwald as soon as possible, so it was put into place, attached to the Lowthers, and warmed up for several days. Since the V20 is an integrated, we decided to run a topology of long unbalanced leads of JENA Labs interconnect from the Linn CD-12. The long interconnects could then be swapped back and forth between the CD-12 and the Sony SCD-1 SACD player.

On the power cable side of the equation, Ron Paquette’s brilliant Sahuaro Audio Slipstream (CD-12 and SCD-1) and Jetstream (V20) power coupling system were put into place. Both Dan Meinwald and Alan Kafton had recommended this cable system highly with the V20. The sources were plugged into the Tice Audio Block III Signature; the amplifier directly into the dedicated Hubble outlets at that end of the room.

The V20 is a unique design, both visually and aurally. Hefty (55 lbs.!), rated at 24WPC (20Hz-20kHz), and completely silent in operation, this Pure Class A integrated (unbalanced only) features an eye-catching layout, plus a very unusual complement of 26 12AX7(!) and 4 12AU7 tubes to do the job. (This is the array that PF’s very own Digital Editor Mike Pappas had trouble believing: "You gotta’ be kiddin’ me!!" Once he heard it at CES ’99, though, he had to admit that it was "a tube amp that doesn’t sound like a tube amp! Great sound!")

Amen to that! The V20 immediately made the Lowthers jump to attention, with terrific dynamics and nicely extended bass. The feel and texture of instruments, either acoustical or electrical, was fine and convincing. I was particularly struck by the effortlessness of the Lowther/V20 combination. At no point did they poop out or sound strained, even when pressed to reproduce highly dynamic passages.

On the CD-12 side of things, I auditioned the Lowther/V20 with CDs ranging from Joni Mitchell’s Clouds (still one of my all-time favorite Mitchell recordings) to First Impression Music’s Here’s to Ben and The Artistry of Linda Rosenthal (both "Editor’s Choice" recordings hereabouts!). With folk, jazz and classical solos, the V20 performed with resolution great articulation. On works of greater dynamic scale, such as Reference Recordings’ Stravinsky: Firebird/Nighingale/Rite of Spring, the incredible slam and sudden transient shifts were rendered with commendable straightforwardness. And from the alternative rock scene, the Foo Fighters’ (a particular favorite of mine!) The Colour and the Shape rocked and sizzled in a way that belied the fact that only 24WPC were driving the show!

It was time to switch to SACD land. A quick re-plugging, and zounds! It’s always amazing to me to compare the improvement that you get when you shift from standard CDs — even out of a source as exceptional as the Linn CD-12 — and go to SACD. Amigos, it ain’t even close!

Pumping SACDs like Duke Ellington’s Blues in Orbit through the Lowther/V20s was an exercise in delight! The Lowthers showed their ability to render texture, tone, rhythm and pacing with startling delineation. Improving the quality of the source had led to a remarkable improvement in the quality of the musical experience at the other end. This was confirmed with such stellar SACDs as Sony Music’s Bruno Walter: Mozart Symphonies 38 and 40, Water Lily Acoustics’ In Nature’s Realm, and DMP’s Steve Davis: Quality of Silence. In every case, the movement to SACD produced a massive improvement in both the resolution of timbre and especially in the presentation of stereo soundstaging. SACD does height, width, and (above all!) depth big time!

So, what can I say? It was clear that the Lowthers and the V20 liked each other very much — and loved SACDs!

For those readers looking for a drop-dead gorgeous integrated, with silent operation, a smashing sound well beyond its wattage, and no-hassle operation, the V20 is simply terrific.

This is a great combo, and rates a Ye Olde Editor’s "very highly recommended."

II. The 47 Laboratory 4706 Gaincard amplifier

Here’s a shocker: imagine a solid-state amplifier that would rest in the palm of one hand, rise to only a little over 1" high, that’s a true dual monoblock design. With an input to output distance measured in a few inches, total. Dual inputs and dual stepped volume controls; grounding posts; built-on mini-tiptoes; a proprietary power input. Nothing else. Visualize an external power supply that’s round, much larger than the amplifier that it powers, exceptionally heavy — and named "Humpty." (Yes, you read that right.)

Now realize that this unique little powerhouse tandem pumps out 25WPC @ 8 Ohms.

Got it?! If so, then you’re imagining the 47 Laboratory 4706 Gaincard amplifier.

Yoshi Segoshi waited more patiently than anyone for us to get the low-powered system together. I appreciated his perseverance enormously, so immediately put the Gaincard into place right after the V20. Once again, we ran long leads from the CD-12 and SCD-1; only this time, we went directly to the Gaincard without any intervening input switching sections. This is one of the few times that I’ve run straight to amp from a source. Normally, I’m not a fan of skipping the preamp; it’s too much bother to switch the leads, and a good active preamp "fills in" the sound, keeping it from being too lean, at least in my opinion.

The results were nothing less than spectacular! I could scarcely believe my ears — the quality of the music coming from the Lowthers was spectacular! For such a small and unusual amplifying system to produce sound of this level of excellence, was a thing unprecedented in my listening room. The Lowthers continued to show their strong suit, an exceptional midrange, as before. But now the bass was at least as well controlled as it had been with the V20 — a tubed mini-powerhouse — and the dynamics were even better than they had been with the V20. The sound was clear, uncolored, effortless, and at ease. High frequency extension was very fine; timbral resolution was detailed, without ever being etched or fatiguing.


To confirm these impressions, I had Tony Glynn come back by the listening room, and had my Assistant Editor, Rick Gardner, sit in as well. Both were struck by the synergy between the Lowther PM2A’s and the Gaincard. Tony was particularly surprised. He knows his Lowthers quite well, and has heard them in tandem with a number of fine preamp/amp combinations. He was completely unfamiliar with 47 Laboratories and the Gaincard. Rick Gardner didn’t know the Gaincard either, but gave it an immediate rave.

"Oh yeah! Now I could really get interested in that!"

Which is high praise from Rick. As an unrepentant rock ‘n roller, he found the sound of the Gaincard with the Lowthers to be far preferable to any of the 2A3’s that he heard in my listening room.

We put some fine SACDs through their paces: the Sony Music Kind of Blue and superlative Mingus Ah, Um; DMP’s Quality of Silence; Telarc’s Brubeck: The 40th Anniversary Tour of the U.K. (love that piano!). The results were superb — never fatiguing, and yet clear, very detailed, unveiled. Which is what SACD does: it delivers master tape or mic feed level signal. In this case, the destination for that signal was sitting us right up in our chairs, getting our heads to nodding and our feet to tapping.

In other words, children, we were connecting to the music.

Tony conceded that the Gaincard did a marvelous job with the Lowthers. "Jeez, I’ll have to remember 47 Laboratory, I guess!" Given Tony’s strong preference for SETs ("I hate those goddamned sand amps!"), this was quite an achievement. Rick was emphatic about it: "Now I could really get into the Lowthers when they sound like that!"

So, for those looking for a heavily dynamic experience ("gotta have lotsa’ slam, dude!") with the Lowthers, or with any other speaker happy with its rated 25 WPC, the 47 Laboratory Gaincard is a slam-dunk.

This is absolutely one of the most surprising and pleasant discoveries in my listening room during the past several years! The Lowther/Gaincard system therefore rates a Ye Olde Editor’s "highest recommendation."


Let’s shift to SET mode:

"Scotty, set phasers on ‘really sweet’!"

III. The Welborne Labs Reveille preamplifer

& Moondog 2A3 monoblock amplifier

Ron Welborne is one of the truly fine people in the world of fine audio. His designs have garnered raves for their combination of aesthetic beauty and wonderful sound. Though I had known of Ron for years, and had friends who swore by his gear, my first direct exposure to Ron’s work didn’t come until VSAC ’98. While at the show, I was quite taken by the combination of detail and sweetness that the Reveille/Moondog synergy provided.

As a matter of fact, it was in the aftermath of VSAC ’98 (which was in the early fall of that year) that Tony and I began to talk about this SET project. (This gives you some idea of the lead-time involved in some of these audio reviews — it ain’t easy to do, amigos! Just ask anyone who’s done it… ) I liked the virtues that I heard there, but wanted to hear it in my own listening room. Even VSAC, which is light years better than your typical big audio show, was not nearly the best place to evaluate what SETs and the Lowthers might do. I wanted to have the Linn CD-12 as a PCM front end, right there next to my trusty fully decked-out Linn LP-12 for the LP sources. Furthermore, SACD had been released since then, and it was imperative that I have a well broken-in SCD-1 when I listened to the SETs.

This was all in place, fortunately, by the time that the SETs started to arrive. When the Welborne Labs gear got here, there was a brief delay while getting the main body of the V20 and Gaincard reviews out of the way. Then I put the Reveille/Moondog system into place, and heated it up for about a week, pumping the occasional music through it before getting too serious.

Ron’s equipment generally comes either in the form of kits, or of fully assembled equipment. The configuration that we listened to was fully assembled. Welborne Labs gives a choice of tube configurations for the Moondog: you can take either the Chinese 2A3’s, the Sovtek 2A3’s, or the single-plate Kron KR2A3’s. (This in the general order of "good, better, best.") The Moondog that Positive Feedback received was tubed with the KR tubes, much to my delight — I had heard much about these, and was eager to try them. Standard power output is rated at 3.25 Watts; the KR’s can be made to deliver 4.5 Watts. The driver tubes are 6SN7’s; the output transformers are made by Electra Print. All wiring is point-to-point, with no PCBs used. As shipped, the Moondog was set for 8 Ohm speakers; not quite a match for the 15 Ohm Lowthers, but OK.

The Reveille preamp is Welborne’s reference piece. It’s a two box dual-mono setup, with a separate power supply mated to the preamp via an umbilical. The power supply consists of two toroidals, each with its own power switch. A pair of high quality stepped attenuators with 24 positions controls volume. Tubed with 6SN7’s, the Reveille is chock full of high quality components (e.g., Caddock, Holco, Hovland) and is wired and connected with Cardas. The Reveille is also non-inverting, a very useful attribute. The inputs are CD, Tuner, Aux/Phono and Tape, all unbalanced. There is one main out and a tape monitor.

The overall impression with the Welborne gear is one of superior quality packaged in a most attractive set of chassis. The walnut trim and polished aluminum finish is definitely a knockout; Ron knows how to build ‘em! I put the Moondogs on a set of Andy Bartha’s Whatchamacallits, which in turn were placed on two Seismic Sink stands, and went off to the races!

The Sound

After the time with the V20 and Gaincard, we were now down into the SET 2A3 trenches: 3-4 Watts, with the kinds of specs that would not attract AES glitterati any time soon. And yet… the sound of the Welborne setup was not what stereotypes would have led me to expect. Instead of rolled-off, polite, or "sweet" reproduction, I found the sonics to be clear, clean, articulate, and well detailed. I was surprised at how much I was enjoying the sense of immediacy and rhythm that the Welborne gear delivered via the Lowthers. While lacking the punch that the more powerful V20 and Gaincard amplifiers delivered, the Moondogs showcased the legendary strengths of the 2A3: a richly delineated midrange, timbral structure, sufficient bass for a quiet foundation to the music, and that certain airiness that is magical!

Another point to praise: the Welbornes were commendably QUIET. No hum, no buzz, no hissing white noise. This cannot be taken for granted; not all designs are so accommodating. I did find that I had to use the Sahuaro’s "easy ground defeat clip" to float the ground with the Moondogs for best noise floor, but once I had done so, I was well pleased with the result.

The dynamics with the Lowthers was also startling. I found that I was able to do most of my listening at 10:00 to 11:00 of volume; no overdriving of the preamp was necessary. At that setting, the Lowthers put more than enough SPLs into the room for comfortable listening, even with groups of 6-8. (12:00 of volume would be enough to drive you from the room!) The Reveille’s presentation of the music was noise-free and neutral, with decent gain; precisely what you want from a fine preamp.

SACDs like the Sony Music Miles Davis Kind of Blue and Sketches of Spain were hypnotic in effect through the Welborne system. Ditto with the SACD of Dave Brubeck, Time Out, or with the very fine Telarc SACD of Brubeck’s 40th anniversary tour of the UK. Or that crème de La crème SACD recording, Ellington: Blues in Orbit — marvelous! It was easy to lean back and rock in my listening chair, close my eyes, and float away on the music. Both the SACD sampler of Joe Harley’s fine recordings, Bluesquest, from Audioquest Music, and Kavi Alexander’s marvelous Fascinoma were magic carpet rides with the Welborne/Lowther tandem in place. Jazz, the blues, folk, small classical solos or ensembles… all sounded delicious with a capital "D"!

My rule is simple: when the toe’s a-tappin’, things is a-happ’nin’!

On the other hand, it is clear that ‘philes who prefer full-range orchestral will have to give careful consideration as to how they will accomplish their discography with SETs. This is not just a challenge to the Welborne/Lowther system, of course; it is a crucial question for any SET. For example, I found that listening to the wonderful Sony Music SACD of Stravinsky Conducts Stravinsky: The Rite of Spring & The Firebird did not have the deeper foundations or the high frequency extension that were clearly presented by, say, the Nova Renditions and the Linn Klimax monoblocks. Or, for that matter, by the 47 Laboratory Gaincard and the Lowthers.

Then again, this is hardly a fair comparison. One cannot — or should not — fault what a system is by pointing out that it is not what it is not. SETs are not, and were never intended to be, high-powered, full range devices, and so cannot be guilty of not being high-powered full range devices. I should also point out that the Welbornes were tapped for 8 Ohms, which meant an unavoidable mismatch with the 15 Ohm Lowther drivers. This may have had some effect on the bass performance of the system, but was not enough to concern either Tony Glynn or myself.

Advice: lovers of full orchestral recordings, as well as those who enjoy rock in its various forms, will have to investigate the properties of their listening room carefully. I found that speaker placement did strengthen the Lowthers’ bass somewhat through boundary reinforcement, though there’s a limit to what can be done with this. (Not to mention the fact that soundstaging and imaging will suffer if you get too radical in pursuing the boundaries!) The Welbornes did fine work within the envelope of the 2A3s, but will not give you the 32Hz pedal on that pipe organ recording that you love so much, nor will it render the opening vocal chorus on the soundtrack to Glory with the profound gravity that it can have (and where so much of the emotion is).

Then again, many audiophiles live in apartments where the successful pursuit of de profundis would lead to an eviction notice, and highly extended upper frequencies would entail a suit for divorce. Not to mention the fact that full range systems are unavoidably large, heavy, demanding beasts with (generally) imposing price tags. Quite apart from musical tastes, there are many circumstances in which SETs may appeal due to the relative ease of setup, relative affordability, and their emphasis on "the glorious first Watt and the midrange thereof!" I can personally vouch for the addictive nature of SETs virtues, which the Welborne/Lowther combination has in spades.

Verdict: the Welborne 2A3s and Reveille paired with the Lowther PM2As are an exceptionally synergistic match, with special strengths in the neutral and detailed presentation of music. Beautiful to the eye; a delight to the ear. It therefore richly merits Ye Olde Editor’s "Highest Recommendation."

IV. The Wright Audio WLA12 preamplifier & WPA 3.5 monoblock amplifier

George Wright’s phenomenal work fools you. You look at the WLA12 & WPA 3.5’s and you think, "Hmmm… very industrial!" There’s no doubt about the fact that the WLA12 preamp/WPA 3.5 are highly utilitarian designs visually — and no danger in confusing the Wright Sound Company gear with the Welborne equipment! Yet the fit and finish is quite professional, and attractive in its own very practical way… no reason to complain here.

Yep, that’ll be your first impression. Then, my friends, you’ll turn it on… more on that shortly.

George was kind enough to deliver his equipment personally. We chatted for a few minutes; he helped me debug a tubing problem with the Fi 2A3s. He’s clearly an unassuming person, though conversation made it clear that he has definite ideas about SETs and how to build them. His design work and execution seems to be modern in understanding and selection, but "golden age" in its sense of what works best. I came away from our brief chat impressed with his knowledge and commitment to his art.

Unlike the Reveille, the WLA12 comes in a single chassis package. The power supply transformer is integrated onto the main board. A complement of four tubes is used: 2x6SN7, 1x6EM7, and 1x6x5. Volume is controlled via left and right continuous pots of Noble mastering-grade, unlike the Reveille with its stepped attenuators. There are five inputs, including a tape loop (but no tape monitor). There is a mode selector, with Stereo, Reversed, and Mono settings, still a very handy thing to have. A mute switch with mute, -10 dB and 0 dB setting, plus a power switch rounds out the front side.

The back panel has RCA inputs/outputs, plus several very useful features: two pair of main outputs (good show!); a high/low sensitivity switch (extremely useful if you want to change the volume knobs range that you’re using on the front end); and a voltage setting for the unit (100, 117, 234 — very intelligent, this!)

A cautionary note for cable tweakers, however: the WLA12 has an integrated cable — no IEC. All wiring is point-to-point, with the very fine Hovland Musicaps used as coupling capacitors.

The WPA 3.5s follow the path of the WLA12 in that this 2A3 design is cut from Spartan cloth. There is no excess of finish, and nothing to get in the way of simple performance. The tube complement consists of 1x2A3 (Chinese Electron); 1x6SN7; and 1x5Y3 American (in this case, Sylvania).1 There’s an unbalanced lead input, a pair of solid binding posts, and (extremely useful for the purposes of this review with the 15 Ohm Lowthers) a multiple tap system for speaker output impedance. It was simplicity itself to choose either 4, 8 or 16 Ohms and screw down the strap accordingly. (I strapped at 16 Ohms during this review.)

The Wrights were placed on Andy Bartha’s Whatchamacallits again, and put on a Michael Green equipment rack. After warming the Wrights up for a day or two, I began listening more carefully. I had enjoyed the V20, the Gaincard, and the Welbornes; would there be any change in the experience with the industrial-look Wrights?

The Sound

I was quite surprised with the results. The combination of the WLA12/WPA 3.5s and the Lowther PM2As was striking! Belying its looks, the Wright Sound gear was exhibited a combination of great dynamics, striking detail, and excellent rhythm and pacing. Music seemed to well up from its commendably quiet noise floor with ease and effortlessness. There was no sense of constriction, nor of "rolled off" higher frequencies; you felt that, much like with the Welbornes, the Lowthers were being taken to the limits that 2A3s would do.

I went back through various reference SACDs with the Wrights: Fascinoma, Kind of Blue, Mingus Ah Um (an utterly incredible disc — buy it now!), Blues in Orbit. In every case, I found that while I was hearing a different presentation of the music than the Welbornes — perhaps just a touch less authoritative, perhaps a bit less detailed, but maybe possessing just a bit more verve — that it was nonetheless immensely enjoyable to spend time with the system. The WPA 3.5’s handled the demanding SACD signal with aplomb, showing no signs of difficulty with the wonderful texture and tone that SACD delivers. Soundstaging and imaging were quite good, while the dynamic punch… the ability to deliver sudden transients convincingly… was excellent. Overall, Wright’s gear was doing things — well — right.

Curious as to whether the gain setting would affect the feeling of the presentation — I had started in the high gain position — I switched to low gain to see if things changed much. (The low gain position drops the volume by about 8 dB, according to Wright Sound.)

Nope. I found that I had to turn up the gain perhaps one "clock notch" (i.e., from 9:00 to 10:00) to match perceived volume, but nothing else seemed different. This seems to be mainly of use to those who want a little more elbow room when setting their gain.

The Wright Sound system possesses remarkable synergy, and, like the Welborne gear, strikes you with a strong sense of coherence. There was a pleasant slam, a real dynamic presence and a tactile sense of "you are there" that gave a sense of being in the front row, even if you didn’t have the last word in bass foundation or high frequency extension. Sometimes that doesn’t matter, I think; sometimes "being there" is enough, especially since "I want it all!" is so very difficult to achieve. (The Holy Grail is tough to reach. Just ask me; I’m still trying… )

Everything works together for good in the Wright Sound/Lowther interface, and that’s saying a lot.

I have to say that while the Welborne gear wins the "drop-dead beautiful award" in this appraisal hands down, I really came to love the sturdy Wright Sound components. Less than classically beautiful, perhaps; but they made wonderful music always, and have become a particular favorite of mine.

I must therefore give them a Ye Olde Editor’s "Highest Recommendation."

And I freely confess to doing so with great affection.

V. The Fi 2A3 Monoblocks

Don Garber is a name well known to aficionados of SETs, but perhaps little known in the larger world of high-end audio. Located in NY, Don has spent years quietly designing and building amplifiers. PF’s Jeff Silverstein has been most impressed with the sound of the Fi monoblocks, as well as with their builder, for several years now.

It would be very interesting therefore to get a pair of the Fi 2A3s into this project. Tony Glynn was able to arrange with Don to send a pair along.

The Fi 2A3s are different in appearance from either of the other two 2A3 amplifers listed. (Come to think of it, all of the systems that I’m discussing are dissimilar in appearance! Radically so. And none of them generates more than 25WPC. Which just goes to show you that there are an awful lot of roads to Rome… ) The amp has wooden feet supporting a silver component platform. Also unlike the other amps reviewed, the chassis of the Fi amp is open on the bottom, exposing its point-to-point wiring. The power and output transformers dominate the upper layout, leaving just enough room for the 1x2A3 (manufacturer undetermined), 1x6SF5, and 1x5R4 tube complement. I assume that since there was no provision for alternative impedance loading, that a standard 8 Ohm was supplied.

I did have just a bit of difficulty in following the manual that came with the Fi amps. Unlike the Welbornes and Wrights, the Fi amps were not fully screened with tube labels. Only the 2A3 socket was identified; the other two were not. The directions in the documentation were also not quite clear, and Tony Glynn and I wrestled with where to put what. Either a tube diagram in the manual, or full screening on the amp, would make the setup phase easier.

The overall workmanship of the Fi is simple and straightforward; the visual effect is compact and understated. Due to the open bottom construction of the amp, I decided to forgo the use of the Bartha Whatchamacallits and placed the Fi 2A3s directly on the Michael Green isolation rack.

Since Don Garber didn’t have a preamp available at the time of this review, I used the Welborne Reveille while listening to the Fi amps.

The Sound

The Fi 2A3 was the only one of the amplifiers reviewed that struggled a bit with transformer hum. Once again, I had to float the ground of the Sahuaro power cords to help lessen the problem, so that I could proceed with listening.

The Fi 2A3’s presentation struck me as more laid back than either the Welborne Moondogs or the Wright Sound 2A3s. The sound was very refined and detailed, with a clarity that allowed me to relax and let the music enter in. The texture of strings, for example, was portrayed convincingly; Yo Yo Ma’s SACD Solo (a wonderful disc for those of us who love cello; the recording was done directly to DSD, which means that it’s about as good as it gets) was lovely in its ability to haunt you with the sheer resin of bow meeting string. The Miles Davis Kind of Blue SACD floated in the darkness of my listening room; "All Blues" had the ache that I’ll always associate with that performance.

On the other hand, the Fi 2A3s didn’t seem to have quite the same authority as either the Moondogs or the WPA 3.5’s. This is a hard quality to define; I would say that it is composed of the ability to render both major and minor dynamic passages (what some reviewers call "macrodynamics" and "microdynamics") with facility; the power to handle transients with ease; and a certain musical "slam" that makes you sit up and say "wow!" J. Gordon Holt used to speak of his "goose bump test"; that’s probably what I mean here.

I wouldn’t say that the Fi 2A3s are "polite" (a term that certainly damns with faint praise), but I would say that they are quieter and seduce you gently over time. They don’t grab you by the ears and haul you off the way that the other amplifiers that I listened to in this project did. They worked very well with the Lowthers, but the synergy between the Fi amps and the Lowthers was more mellow than any of the other combinations that I listened to. You might want to experiment with tubes, power cords, and interconnects here, to get more out of the system.

Overall, I would say that the Fi amplifier would be of interest to listeners who value serenity and a reflective presentation of the music above all else. (After all, not everyone is a rock ‘n roller!) You won’t be able to go pedal to the floor with the Fi 2A3s, but within its envelope, the sound is involving and richly textured in timbre. Lovers of small jazz groups (especially with smashing vocals — check out, for example, the SACD of Billie Holiday, Lady in Satin if you want your heart broken), classical ensembles/chamber music, and solo stringed instruments should give careful consideration of the Fi 2A3s.

Like their designer, the Fi amplifiers are quiet, unpretentious, and civilized. If this is what you are seeking in a 2A3 amplifier, then by all means give the Fi’s a try.

The combination of the Fi 2A3s with the Lowthers rates one of Ye Olde Editor’s "Highly Recommended" evaluations.

Final Thoughts

To summarize some practical wisdom that I learned along the way:

* Power cords make a difference. The Sahuaro Slipstream (sources)/Jetstream (amplifiers) combination opened up the presentation of soundstage, and extended the upper range nicely. The combination of SACDs, SETs, the V20, the Gaincard and the Lowthers was enhanced by the Sahuaro cables, which became my cord of choice in this project. Ye Olde Editor’s "Highest Recommendation"!

* Interconnects also make a difference. The JENA Labs interconnects and speaker cables performed spectacularly well; I reiterate my enthusiastic recommendations for these, as well.

* The Lowthers in the Medallion II cabinets are a surprising speaker. Coherent, dynamic, and very fine in their soundstaging/imaging. They require careful placement, however, for maximum bass response. If you really need to have the bottom octave, then you will likely have to look elsewhere — though you should at least give a listen to what the Lowthers can do in your setting. You should give consideration to your taste in music, your library of recordings; only then can you decide. Deep bass in and of itself is no panacea, no formula for delight. It is only one factor in the complex world of audio reproduction, and obsession with bass is no better than any other obsession. All things in proportion…

* If you like the Lowthers, but really would like to have greater dynamic slam and more bass, then check out the 47 Laboratory Gaincard or the E.A.R. V20. Either of these will give you remarkable resolution, plus greater power for the Lowthers.

* With SACD sources or good LPs, you should have minimal problems with rolled-off high frequencies with SETs and the Lowthers.

* The Bartha Audio Whatchamacallits are simple to use, and make effective audio isolation devices. Plus they are strange and cool! Recommended for use with SETs.

* While we concentrated on SACDs for this article, I note once more for the record that the SCD-1 is a world-class CD player in its own right. As of this writing, only the Linn CD-12 has the final edge in the reproduction of standard CDs with the Lowthers and any of the preamps/amps that we listened to. Conclusion: get thee to SACD!! No other "tweak" or system upgrade will have anything like the impact that SACD sources will. Period.

* While I didn’t get to do it during this project, comparisons among the various SET tubes and topologies made it clear that you shouldn’t be afraid to experiment with some inspired tube rolling. The KR 2A3s impressed with their greater punch and detail; I can see why Ron Welborne provides them as an upgrade to his Moondogs.

As I said at the opening of this article, SET involves a "willing suspension of disbelief" for those of us more accustomed to full range listening. If you are unwilling to set aside preferences, you will find it impossible to enter into the delights that flea powered triodes like the 2A3s can provide. The opportunities that they give for the exploration of the purity of tone, the texture of timbre, the roundness of space, and the sense of presence are not to be missed if you are a true audio connoisseur. Without this experience, you will not have rounded out your audio education, and will be incomplete in your appreciation of what SETs have to offer audio. You will also misunderstand why so many audiophiles have chosen to pursue low-powered single-ended triodes, and what entrances them in their audio quest.

There are reasons why talented designers like Ron Welborne, George Wright, and Don Garber do what they do. Companies like E.A.R. and 47 Laboratory are breaking the rules and departing from convention, with results that are nothing less than magnificent. They beckon us in directions that we have not been, and invite us to travel new paths.

Are you willing to enter in?


Current Pricing

Lowther America
P.O. Box 4758
Salem, OR 97302
503-370-9115 (voice)
503-365-7327 (FAX)

PM2A drivers, $1,270.00 per pair
Medallion II cabinet kit (pair), $1,200.00
Medallion II cabinet pair, finished, $1,950.00
Upgrade internal wiring to JENA Labs, binding posts to EP Music (as reviewed), $180.00
All drivers are available as either 8 or 15 Ohm, no extra charge
To change to silver voice coils, add $70.00 per pair
Average cabinet shipping within the USA, $225.00

1087 E. Ridgewood Street
Long Beach, CA 90807
562-422-4747 (voice)
562-422-6577 (FAX)

E.A.R. V20, $4,595.00
Sakura Systems
2 Rocky Mtn. Road
Jefferson, MA 01522
508-829-3426 (voice/FAX)

4706 Gaincard, $1,500.00
4700 Power Humpty, $1,800.00

Sakura Systems features the complete line of 47 Laboratory analog and digital products; call or email for complete price sheets

Welborne Labs
P.O. Box 260198
Littleton, CO 80126
303-470-6585 (voice)
303-791-5783 (FAX)

Reveille Linestage Kit, $1,595.00
Reveille Linestage assembled, $2,295.00
Moondog 2A3 monoblock kits
With Chinese 2A3s, $1,450.00/pair
With Sovtek 2A3s, $1,550.00/pair

With Single-Plate KR2A3s, $1,825.00/pair
Moondog 2A3 monoblocks fully assembled

With Chinese 2A3s, $2,095.00/pair
With Sovtek 2A3s, $2,195.00/pair
With Single-Plate KR2A3s, $2,495.00/pair

Wright Sound Company
3516 South 262nd Street
Kent, WA 98032-7047
253-859-3592 (voice)
253-850-1859 (FAX)

WLA12A preamp (replaces the preamp reviewed, with a single volume control instead of dual mono controls, and a shunt type balance control), $679.00

WPA 3.5 monoblock amps, $1,198.00/pair with Chinese 2A3s (as reviewed); with Sovtek single-plated 2A3s, $40.00 additional/pair

30 Veranda Place
Brooklyn, NY 11201
718-625-7353 (voice)
718-875-3972 (FAX)

Call for current pricing; no web or email address currently available.

19235 Pilkington Road
Lake Oswego, OR 97035
503-639-7551 (voice)
503-968-7261 (FAX)

Call for current pricing on all JENA Labs interconnects/cables.

Andy Bartha Audio
4680 SW 74th Terrace
Davie, FL 33314
954-583-7866 (voice)

Small whatchamacallits, $10.00 each

Medium whatchamacallits, $15.00 each

Large whatchamacallits, $35.00 each