Close Encounters of the Silicon Kind
Lynn Olson

Received Wisdom

One of the unsettling things about being both a reviewer and a designer is having the "conventional wisdom" knocked on its head on a regular basis. Those of you who’ve read my articles here in Positive Feedback, and who also read Sound Practices magazine, know about the commandments of ultra-fi:

* Thou Shalt use direct-heated triodes, preferably in single-ended circuits.

* Thou Shalt use Class A circuits only, never Class AB.

* Thou Shalt Not use feedback, even unto the least part.

* Thou Shalt Not use regulation in power amplifiers, since the regulator itself relies on feedback.

* Thou Shalt always use exotic parts, consisting of silver wire, metal-foil caps, and non-magnetic tantalum-film or carbon-composition resistors.

All well and good, with my experience with the Audio Note Ongaku, the Reichert Silver 300B, the Cardinal, and the MagneQuest Silver 2A3 confirming these assumptions. Then I got a call from Mike McCall to come and collect the RE Designs LNPA-150 monoblock transistor amplifiers. I drove down to the charming little town of Silverton, listened briefly, collected the amps, returned to Aloha, and gave the amps a once-over. Frankly, I didn’t expect much, particularly after I opened the cover.

The circuit is a conventional complementary-differential front end, the second stage is complementary, and there are 2 stages of complementary emitter-followers for current gain. As far as I could tell, about 95% the same as my 20-year-old Audionics CC-2 or millions of other transistor amps out there. Parts-wise, there’s a single-sided G-10 fiberglass circuit board, standard-grade 1% metal-film resistors, standard-grade electrolytic caps, Motorola transistors, and ordinary-looking 18-ga. hookup wire. Nothing too amazing here either.

I looked a little further and saw that about half the space inside is consumed by a large discrete regulator board, with (surprise!) independent toroidal transformers for each plus and minus rail, along with independent plus and minus rectifier bridges as well. Well, I can certainly see why RE Designs claims 75W into 8 ohms, 150W into 4, and 300W into 2 ohms — the powerful regulation and the sheer size of the raw supply will assure nearly unlimited current delivery. In effect, the regulator section is an amp-within-an-amp; it’s just as big as the "amp" itself. In addition, the big power supply electrolytics are on the far side of the regulator; there’s only 100uF of bypassing between the regulator and the amp proper, so you’re hearing the sound of the regulator, not the power supply.

The cover goes back on, and everything gets connected. Yes, these are definitely Class AB, since they don’t get very warm at all ... a true 75W Class A amp would scorch my hands on the heat sinks by now. But what’s weird, even from turn-on, is that the LNPA’s don’t sound a bit like what you’d expect. No transistor sound. No MOSFET mist. No low-level grunge, even when I listen to music very quietly through the 92dB/metre Ariels. After maybe 1/2 hour to an hour, the sound gradually opens up a bit more. But there aren’t any dramatic tonal balance shifts as it is kept on over the next several days and weeks, and thanks to the regulation, it is pretty much immune to the usual variation in sound quality between late afternoon and after midnight.

The LNPA’s share the chameleon-like quality of the Ariels in passing on the sonics of the preceding device. People keep asking me what the Ariels sound like, and the answer basically depends pretty much on what amp is connected. Well, the same applies the LNPA ... it really has very little sonic character of its own; indeed, most interconnects have more coloration than this amp! You might be thinking, "well, yeah, but everything is getting all homogenized, hifi’ed, and smoothed together by the feedback, right?"

Wrong. It is very revealing of both audiophile minutiae like squeaking chairs and the expressive, emotional qualities of the performance. The LNPA-150s sounds nothing like the typical hyper-detailed audiophile transistor amp, and indeed is closest to the VAC 90 and the Wavelength Audio Cardinals in overall presentation. In other words, no transistor sound at all — relaxed, unstressed, very fast and open, and a remarkable similarity to the top rank of pentode amps and the upper range of the triode amps. Just for grins, a friend brought over his parallel, single-ended, non-feedback triode amp based on the new Svetlana SV811 triodes; well, the transistor LNPA-150 and the triode SV811 sounded almost identical, despite radically different design philosophies.

The LNPA-150 also has an intriguing quality to the depth presentation; the sound actually comes up to you and laps at your knees, instead of the way, far away soundstage of many audiophile amps. I don’t mean the sound is "forward" in the mundane sense of a prominent midrange; that’s not the case at all, since the amp is sonically quite neutral. Instead, the soundstage actually comes right up you, giving a intimate reach-out-and-touch-it quality to many performances. So while a few sounds are behind the speakers, in the usual way, some are near the speakers, while others move right up to you and tickle you, almost like 3D headphone stereo. It’s kind of hard to go back to the usual look-but-don’t-touch clinical audiophile presentation after living with this amp.

In comparing this amp to the latest audiophile confections unveiled at the Winter 1995 CES, I’d have to say this one is still my favorite at any kind of sane price point. It’s the only transistor amp I’ve heard so far that has soul and body to the sound, with a remarkable ability to convey the emotional tone of the performance; this is the normal preserve of the direct-heated single-ended 2A3 and 300B triode, not transistors arranged in the usual complementary-symmetry topology.

So much for the conventional wisdom, eh? Karna, my sweetie, was so taken by the overall quality of the sound she lobbied heavily for us to buy the amps outright ... and this is the lady that was converted to ultra-fi by the Ongaku experience. I was just about to mail the check (and people who know me know how rarely I buy a major piece of equipment) when my transformer-building chum Michael LeFevre shipped me a pair of custom Peerless S-230-A transformers with M4 laminations.

Argh!!! What to do? The bird in the hand versus the long-awaited amplifier project?

Once again my reviewer-self and designer-self are in conflict. The designer-self got the upper hand (this time), so other folks can enjoy the LNPA’s while I build.

I have to say, though, that this marked the third time I’ve packed up an amplifier with a genuine sense of regret (the first two were the Audio Note Ongaku and the Reichert 300B’s).

Well, at least I had a consolation prize. My front end is finally sounding good, with the Supermod Monarchy M-33 DAC/Line Stage and Monarchy Model 30 Laserdisc/CD transport. Stan Warren of Supermods re-designed the analog sections of the M-33 DAC and the separate line stage. My Tektronix buddy Matt Kamna and I then took it a step further with Audio Note Black Gate power supply caps and Audio Note Shinko tantalum-film resistors. (This whole setup is now available as the "PF Supermod" for the Monarchy M-33.)

What’s it sound like? Nothing like the stock M-33, which is a very good DAC and preamp in stock form. As far as I can tell with my system, the "digital" sound is gone. Finally. No digital screech, no high-level edginess, no grain-n-crud on the noise floor, no weird airless decay tails at low levels, no Santa Fe Bugle look-at-me hyper-etched sound. About time, even if it is 15 years late! In positive terms, the words that come to mind are "master tape" and "direct-disc." It’s really that good. How about the really rotten-sounding CD’s? Well, they just sound like badly EQ’ed and distorted master tapes. (And yes, Clark Johnsen’s CD degaussing tweak still makes a big difference, particularly for the really shrill CD’s.)

I was really curious how this thing sounded compared to other DAC’s, since what I was hearing sounded so very different than any DAC or CD player I’ve ever heard before ... and I’ve heard a few, and didn’t like most of them. I took the whole shebang over to an old hi-fi-nut friend and fellow Positive Feedback reviewer, Dr. John Coletti, who has the top-of-the-line ESP speakers, huge CJ monoblock amps, a well-reviewed $3000 tube preamp, and the Levinson 30.5 DAC and matching Levinson transport. Yup, Future Boy Vinnie of Sound Practices fame is right. The Levinson 30.5 is de best, with no, repeat no, CD crud or nasties, real sweet sound, and way more detail, space, and air than CD’s have any right to. (I didn’t hear any of the audiophile-analytical "Levinson Sound" I was expecting.) The sound from the Levinson 30.5 is dramatically better than other DACs in the $1000 to $5000 price range. By comparison, everything else I’ve heard is either a little or lot more colored, and has trouble at high levels. By contrast, I never heard any breakup from the 30.5, which was a first for me. I always thought that CD’s inevitably got gross sounding at high levels. Nope. Vinnie’s right, even though it hurts a bit saying it in public. (I still don’t like mono, though!!!)

The real surprise was comparing the M-33 in various connections as a stand-alone DAC, then a line stage, then both together. On most CD’s, the 30.5 and M-33 sound nearly identical! Weird! Almost like Levinson Lite! At the absolute max levels, where most DACs get that broken-glass sound or dissolve into a blur of noise, the Levinson sailed right through, while the M-33 got a bit crunchy, but not to the point of distress. Frankly, I was more than startled at what I heard. It’s very unusual when two products from totally different designers end up sounding the same ... especially when there is a more than a 10:1 price ratio. To Coletti’s surprise, the Supermod M-33 line stage turned out to be superior to the rather expensive tube preamp he was using ... but that didn’t surprise me too much, since 12AX7’s aren’t going to be real happy driving 15 feet of expensive coax between his preamp and power amps. (When you read Coletti’s review of the ESP speakers in this issue, I should mention that the preamp he mentions in that review is not the preamp we compared to the M-33. That preamp made a quick exit after the M-33 listening session.)

I was feeling like the cat that ate the canary until I heard the Stan-modified TEAC CD player at Hiroshi Ito’s place in Hawaii. Despite the totally different system, the LP-like signature of Stan’s unit was immediately obvious. After all, I’ve sunk about $2500 into the assorted stuff for my front-end; well, as far as I can tell, the Stan-player is at least 90% as good ... maybe just a mite softer and mellower when things get real active, but otherwise real similar. The Stan-player, by the way, is all of $500, and starts life as a Costco/Price Club $129 TEAC CD changer. I don’t really expect any of you to believe me, particularly after the ridiculous Corey Greenburg CD3400 fiasco, but that’s what I heard.

Back on the home front, my own system greatly benefited from the Nirvana cable collection. I tried ‘em all, the digital cable, the interconnect, and the speaker wire. Normally I’m scared of reviewing stuff in this price bracket (several hundreds of dollars each), but I have to admit they’re good value.

One thing I really dislike about cables (and reviewing them) is the audiophile-tone-control aspect of the things. The very best cables can be mighty touchy about interface issues, which is a diplomatic way of saying they can be really bright or dull-sounding depending on the source impedance of your preamp and weird things like that. So the usual drill is to try something that’s ultra-deluxe (99.99% pure silver comes to mind here) and discover, oh yeah, man, all this transparency is really cool, but the tonal balance is way out of whack. So you mess with various preamps and such until you find a "good match."

Frankly, this is a drag.

If I wanted a tone control, I’d rather mess with various brands of 6SN7’s and the speaker crossover, not cables. When it comes to wires, I take a Joe Friday "just the facts, ma’am" attitude. This is where the Nirvana’s come in. Yes, by my cheapskate standards, they’re expensive. But they are very neutral, with no real coloration I can detect, and more importantly, they let the sonic character of the associated equipment shine through. When I switched to other cables, a good part of the magic of the Supermod M-33 or the LNPA-1 amps simply disappeared, replaced by the "sound" designed into this or that tweak cable.

There is a definite synergistic effect when you use the Nirvana digital and interconnect cables together, with a major step forward in ease, naturalness, and "vitality" (thanks, John Pearsall!) that puts the Nirvana combo firmly in high-purity silver territory (but without the associated matching problems). When I tried the Nirvana speaker cable, the LNPA-1’s had long departed, replaced by a somewhat temperamental Class A transistor amplifier. This amp turned out to be very cable sensitive. The Nirvana speaker cable was the only one that could coax a subjectively flat spectrum from it. Normally, power amps aren’t all that picky about speaker cables, and I usually hear much bigger differences when I swap digital or analog interconnects. (Don’t ask me why, except that signals at lower levels driven by millivolt amplifiers are more easily degraded.)

The Nirvana cable line, as far as I can tell, is deliberately not engineered to have a certain kind of sound. This greatly simplifies component matching problems, and lets you confect a system to your own tastes. Since the transparency is in the "very high" to "ultimate" category, what you’ll hear will be the equipment you’ve got.

I feel a mite odd recommending this, but the $500 Stan-modified TEAC CD player combined with $500 of Nirvana interconnect would actually be an outstanding combination, even though the price ratios seem utterly skewed in favor of mere "wire."

If you’ve got an Audio Note Kit One, or another good triode amp with a built-in volume control, you’d be nuts not to try this combo. Your friends would laugh at the cheap-looking CD player, the steam-punk industrial look of the Kit One, and the audiophile-deluxe appearance of the Nirvana ... but the laughing would stop once the music came on.

If the Goddess of Good Fortune has smiled on you, you might have even more fun with the items below:

Products Reviewed:
Ariel Version 2.2 Loudspeakers
(Described in previous issues of Positive Feedback)

RE Designs LNPA-1 Monoblock Power Amplifiers
617-592-7862

Monarchy M-33 DAC/Line Amp with Stan Warren Positive Feedback Supermod
Monarchy DT-30 Laserdisc/CD Transport
Monarchy
415-873-3055

Stan Warren Supermods
541-344-3696

Nirvana Audio Accessories
516-285-1950