Our story to date:

Couple years back, when I did some double-blind tests on a bunch of power amps, my basic conclusion was that studio amps were all pretty much alike, pretty good, and that the main issues were power headroom and damping factor. Since that time, I’ve just not been worrying about power amplifier issues. Been there. Done that.

Recently, a guy named Dan Banquer, who builds audiophile-quality power amps (R.E. Designs LNPA 150) brings a pair of amps over one Saturday for your usual critical listening session.

These amps’re big monoblock units. Modest rated power, about 80 Watts, expensive at $2700/pr, but not totally whacked like some of the really pricey audiophile units. Banquer sez they’re really quiet for power amps. We measure the noise floor at around -80 dBu at full gain, which is about 120 dB dynamic range. Not shabby - enough for 20-bit anyway. Also, they have no cooling fans, don’t hum or buzz. Better and better.

Put up some music. System sounds decent, damn decent. Cue up my current “test” CD (Arvo Part “Credo”), which at its loudest it sounds like someone dropping a Mosler floor safe down a stadium stairwell during the 2nd OT of an NBA playoff game. When I run at reference levels during this passage, my usual amp ‘n monitors get just a little, er, “hard.” Banquer’s LNPA 150s sound a good bit more transparent. Set up the TEF ‘n B&K mic, do a Noise Level Analysis. Lmax (the highest level measured) is around 109 dB SPL. Hmmm. Orchestra sounds really solid and full, but definitely not “hard” or even particularly loud.

Listen to some other stuff. Pink Floyd’s “The Wall.” It sounds really open. Phantom images are really solid. Speakers sound great. I’d like a little more level, though. Add three dB. Now we’re getting somewhere. TEF sez Lmax hits 112. Actually, it doesn’t sound that loud.

Put on some laid-back acoustic vocal stuff. Add level. Sounds really nice. Full, accurate, detailed, smooth. TEF sez Lmax is 114 dB SPL! Leq (sorta like 0 VU) is up to 103 dB SPL. Egads! What is going on here?

You gotta understand. My normal listening reference is 85 dB SPL, and peaks might hit about 95-100 dB SPL. When I get to sustained levels of about 95 dB SPL with peaks of around 107 dB SPL, my amp ‘n monitors generally begin to hurt my ears. FYI, I’ve never, repeat NEVER EVER, run that system, with its 250 Watts per channel, at sustained levels of over 100 dB SPL. Yet here’re these 80 Watt monoblocks effortlessly cruising at well over 100 dB SPL. And it doesn’t sound particularly loud, just full! Amazing!

Using These Amps Over Time

Dan left me the amps to try for an extended length of time. They’ve run effortlessly, transparently and cool. A pleasure to have in place. When we showed my monitors to major manufacturers at the AES in LA, we took along the LNPA 150s as our amps of choice (Thanks, Dan!), and once again, they performed beautifully. One designated Golden Ears said that our demo was the best thing he heard at AES! I don’t know quite what I’m gonna do when Dan asks for the amps back.

What It All Means

My September ‘94 article on amps said that all amps sound pretty much the same, except when you overdrive them, and that you might be wisest to buy the cheapest amp that has adequate power. My experience with the R.E. Designs LNPA 150 has made me rethink that.

Here are some pretty expensive power amps, meticulously designed and constructed (Dan says that the parts cost for these amps is around $1,300, which actually makes them excellent values for the price). They are very conservatively rated, and really aimed at the audiophile market.

But that rated power output is a little misleading. With a very low output impedance and a really massive power supply per channel, the amps will supply really impressive short-term power with no distress, well beyond the limits of my normal amp, with no trouble. At the same time, they are very carefully protected, so that you would have to be a serious cheesehead to damage them.

$2700 is a lot to lay out for a power amp. But, when you get to that happy point in your professional success curve where you no longer have to scrimp quite so much, where you can begin to push the quality envelope a little and indulge yourself a little, well, amps like these might be a really good item to consider to help jack up the basic quality of your monitor path.

One of the signatures of really linear playback components is that as you crank the level up, the sound never seems to get really loud, just fuller. You don’t get that pain cue that comes with the onset of non-linearity (the beginning of distortion – what I think of as “hardness”), and that effect is both really pretty impressive and quite comforting in studio work. The R.E. Designs LNPA 150 monoblock amplifiers have this quality in spades. Thanks, Dan!

R.E. Designs
43 Maple Ave.
Swampscott, MA 01907
917-592-7862

Dave Moulton is trying to stay below clipping, but his power supply is a little marginal these days.