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Re: Any opinions on the RE Designs LNPA-150 amplifiers?

207.69.137.136

I've been a proud owner of Dan Banquer's LNPA 150 monos, as well as Dan's amazing SC{PA preamp, and his homebrew speaker wire and interconnects, to boot. This has been the end-of-the-road audio system for me, having previously fallen into a terrible buy-sell-buy pattern which cost me a great deal of money and unhappiness. Dan is the man--He's an audiophile, a musician, and an electronics engineer who makes each component himself by hand. His plain-spoken expertise is refreshing, especially having fallen victim to many snakeoil salesmen who, regrettably, prey upon music lovers. Do yourself a big favor and listen to RE Designs components and, like me, this could be your final, and finest, system. By the way, below is Lynn Olson's review of the LNPA 150...

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.

The RE Designs LNPA 150

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).


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