| Let me begin with the ceremonial opening of the can of worms... How
many times in the last several years have you heard, or read, the statement, "...a
solid state device that sounds like tubes"? Why, these days there's even a
manufacturer claiming that not only does his solid state amplifier have a soul, it's the
soul of a triode!
That's not to say his amplifier doesn't play music well (I, ahem, haven't heard it);
I'm talking about this business of sounding "tube-like." Pardon me, but what
about those of us who really don't think that's something to strive for—much less to
brag about?
Now before all you tube folks gather up rocks to drive me from the editorial masthead
(people who own glass audio shouldn't throw Shakti stones—or something...), be
forewarned: It isn't that I'm anti-tube per se. Why, some of my best friends own tube
systems. In fact, I've even owned a few tubed pieces myself, and some noctilucent
amplifiers were used during this review period.
I think some of the obvious strengths of tube designs lie in the fact that they are
very simple circuits. Less is more. But then, there's that mellowness, that warmth, that
liquidity, that what-have-you stuff (which, taken to its worst extreme, makes everything
sound the same). And then there's this single-ended silliness, this low power, narrow
bandwidth, high noise, high distortion stuff...
All this begs some questions. Is it because these single-ended amplifiers are tubed, or
is it he fundamental circuit philosophy itself that makes them so capable of conveying the
musical message?
And what if somebody applied this single-ended business to a solid state design?
And: Instead of attempting to match the current/voltage characteristics of this or that
amplifying device, what if they based their design on the of the medium of sound itself:
Air? Would this thing sound like "solid-state" or "tubes?" Would it
finally and simply transcend the difference between the two and sound like music?
One day while out on an audio foray, I stopped in to see my friend Dave Mercincavage at
Acoustic Images, in Vestal, New York. He had called me several weeks earlier and said he
was getting in the new Pass Aleph 3 power amplifier and Aleph L preamplifier. Dave thought
I should give them a listen after he got them all loosened up (This man knows my tastes
well, of which the invitation is proof).
The Aleph 3 power amplifier and Aleph L preamplifier are the least expensive models in
the relatively new line of electronics from Pass Labs, named after Nelson Pass, formerly
of Threshold. The Aleph 3 power amplifier is rated at 30 watts per channel into an
eight-Ohm load, and sixty watts into four or two Ohms. It's a small unit, almost a cube,
basically looks like one big heat sink: Ninety percent of its sides are nothing but big
cooling fins. People who have seen it in my system have likened it to a sea urchin and
even a porcupine.
On the front (which is hard to distinguish from a side—there's that sea urchin
business) is a single blue LED set way back between those aforementioned cooling fins;
this lets you know the thing is powered up. The back of the amplifier has a 3 inch-wide by
6-inch-high space which is not heatsinked. In this tiny space are stuffed two RCA phono
inputs, the five-way speaker binding posts, an ON/OFF switch, and an EIC input for the
detachable power cord.
There's not much room to work in, and once you've wired up the speaker cable, the
ON/OFF switch is beneath them and damn difficult to access. The speaker outputs are very
rugged, and solidly attached to the heavy aluminum case. This is good, because when using
a large diameter cable with a thick spade, such as my RC Audio Reference bi-wire cables,
you need a nut driver and some torque to make sure things stay put. Things are definitely
easier with a smaller gauge cable and banana plugs.
The Aleph 3's technical claim to fame is that it is a pure class-A, single-ended
device, having only two gain stages. For those of you unfamiliar with the classes of
operation in power amplifiers, class A operation means that the amplifying device (tube or
transistor) is on all of the time. If you think of a car, think of one where the engine is
set for a really high idle—always revving where the engine develops good torque and
power, whether at a traffic light or in the passing lane. So you won't be surprised to
know that the Aleph 3 draws 250 watts from the outlet all the time— 250 watts to
produce 30 watts output. (Whatever you're not using to drive your speakers is converted to
heat; hence the prodigious fins.)
The Aleph 3 does not lend itself to being left on all the time, and that's why I
maintain the placement of the power switch is wretched The amp runs hot, uncomfortable to
touch within 30 minutes or so. Even the RCA plugs on my cables get warm after listening.
Then there's the Aleph's single-endedness. (For a good explanation of all things single
ended, as well as Listener's first review of an see amp, see last year's Autumn issue,
otherwise known as Vol. I, No.4.) No other design approach has been so controversial in
audio circles! The Aleph 3 also uses absolutely no negative feedback. With only two gain
stages, it is a very simple circuit. This is good. Less is more. Less circuitry means
fewer components in the signal path, fewer electronic devices for the music to navigate,
and less meddling—or so the thought goes.
But unlike the Cary or the Audio Note amps Art has already reviewed, the Aleph 3 is a
solid state product. No tubes or output transformers. The Aleph 3 uses transistors for
output devices. It is a single-ended solid state amplifier. I was intrigued.
The entire package is buttoned up in very heavy machined aluminum panels, all bolted
with hex-head bolts. It does not invite internal viewing. Looking at it does not cause my
curiosity to overwhelm my almost certain conviction that it cannot be put back together
again! Call me a coward if you must...
The Aleph L preamplifier, which to some extent matches the design sensibilities of the
Aleph 3 amp, is another piece based on the "only what you need to get it done"
philosophy. It too is made from very heavy machined aluminum panels. On the front are two
knobs and another blue LED. One knob is the input selector for one of the four inputs, the
other is the volume control. That's it— no balance control, no mono switch, no phono
input. Spartan, to say the least. The back panel has the four inputs, two outputs
(subwoofer? biamplification?) and the EIC jack for the power cord.
And, speaking of the power cords, my answering machine has a heavier duty power cord
than these units. Pass says the design does not require heavy duty power cords, and, yes,
my experience thus far has borne that out. I've yet to put a cord on them that made one
bit of difference.
The Aleph L does invite inspection, though. In particular, there's a user adjustable
DIP switch inside to change the gain setting. The Aleph L is shipped with its switch set
for 6.5dB of gain, but the user can remove the top cover and change the setting to 1 3.4dB
for lower output sources, or set it to OdB of gain, like a passive preamp.
Take out the bolts, remove the top cover, and what you'll see is, lots of undeveloped
real estate. The Aleph L is also a pure class A, single-ended device, and there's not a
lot to see in there. Of course, you tube-o-philes are used to that. (But there aren't any
of those little glass pinnacles on the chassis landscape either.) Minimum circuitry,
maximum signal transfer. I cannot help but conclude that there is more production cost in
the metal work than there is in the circuit. Art would be quick to point this out, I'm
sure. In fact, there's probably enough room in there that you could stuff some old tubes
in if it makes you feel better, or maybe even a bottle (shades of Ray Milland in the Lost
Weekend!).
Somewhat unconventional is the placement of the volume control in the signal path.
Where many preamplifiers route the incoming source to the volume control (at some point in
the active circuitry), the Aleph L places it at the other end:
The control attenuates the output of the preamp, I as opposed to attenuating the input.
(I've seen other manufacturers use this method, and what it means is that the output
impedance of the preamplifier changes with the setting of the volume control. This could
be a potential problem with some power amplifiers from other manufacturers, but I feel
it's clear that the Aleph L is intended for the Aleph 3 power amp.)
Anyway, back to Dave's store. He had set up a pair of Aerial Acoustic Model 7s in his
main room, with the intention to audition the Pass combo for me on these speakers. Yeah,
right. A 30-watt amplifier is going to drive those!
And yet: Using a competent Micromega digital front end, and driving my long-term
reference speakers, I was hooked. Throughout the course of several hours of listening, I
resolved to begin by asking to take them home and listen at my leisure, resorting later to
harder measures if need be. Dave, being the affable but insidious fellow that he is, put
them in boxes and away I went.
Obviously, he never got them back. Just to illustrate how thoroughly I have wrung out
the Pass combination, over the ensuing months I paired them with the following speakers:
Alon Is, Alon Petites, Ruark Crusaders, ProAc Response 2s, Acoustic Energy AE2as,
Meadowlark Acoustic Kestrels, Harmonic Precision Echelons, and Aerial Acoustic Model 5s.
There may even be one or two I forgot to write down.
What I learned from these pairings is that the Aleph 3 seems to prefer lower impedance
speakers that are also stable loads across their frequency range. (When a system has a
lower impedance, the Pass has a higher output, and you can avail yourself of about twice
as much power .) My best guess is that if your speaker system has large impedance changes
in varying frequencies, they will not sound the best with the Pass.
Listen to John Lee Hooker's Chill Out (Pointblank Records 7243 8 40107 20), Cut No. 6,
"Tupelo." The studio is clearly fleshed out, thanks to lots of low level decay.
This sense of space is not lost in the positively explosive attacks of Hooker's guitar.
Or try Cut No. 8, "Annie Mae." There's effortless weight and slam with the
Aleph 3/L combination.
The Musical Heritage Society's The Classical Collection, Vol I (MHS 53281 4L) has two
pieces worth hearing on any system, but will underscore my point about the Aleph 3/L
combination. Mendelssohn's aria, "O For the Wings of a Dove"—with soprano
and chorus and ending with pipe organ—shows the speed and low level resolution of the
pair. And Wagner's "Siegfried's Funeral March" will stress the dynamic range of
any system. The huge crescendos will show you just how much muscle 30 watts really is. You
may wish to rethink that big brute of an amplifier you've been dreaming about.
Everything I listened to was presented with incredible harmonic and timbral accuracy,
with truly stunning contrasts and dynamics. I found (and still find) myself playing just
about anything and everything I can get my hands on. For several days in a row the Mamas
and the Papas Greatest Hits did not leave the DAT deck—not the best quality recording
to be sure, but recording quality simply does not interfere with the conveyance of the
performance. The Pass combination does the best job of "getting out of the way"
of the music that I have ever had the sheer escapist pleasure of experiencing in my home.
Is it perfect? No. It is still a thirty-watt amplifier, although it does not behave
like any other thirty watts I've ever seen before. Within its boundary-stretching
limitations, I would rank it amongst the very best available, regardless of price or power
output.
My only real complaint concerns the Aleph L preamplifier. Sometimes, just sometimes,
the "precision 123-step attenuator" will drop a channel when changing the volume
setting. A simple twist of the knob restores it, and I have not noted any imbalance in the
exemplary imaging of the system. Still, considering the low parts count and the obvious
expense lavished on the box they're contained in, I think this is out of line in a $2,000
preamp.
The Aleph L preamplifier is an utterly transparent line stage, world class even. But
with only two knobs on it, if one of them doesn't work right all the time it's a fifty
percent problem in a sense.
There are now a decent choice of preamplifiers available in and around the $2,000 price
point. Many of them represent significant improvements over preamplifiers selling for
three times the price just five years ago. There is really something for everyone's
predilection, whether it be tubes or solid state, full function or absolute minimalist. My
experience with the Aleph L is reflected in my allocation of checks and stars.
At $2,300, the Aleph 3 power amp may initially strike you as an awful lot of money for
a 30 watt per channel amplifier, but when you experience its virtues of speed, dynamic
impact, refinement of subtle contrasts and truth of timbre, or against any of the triode
single ended amps (which can be significantly more expensive and have yards of wire in
their output transformers to boot), I think what you'll discover is that the Pass is
indeed amongst the very best available.
In spite of the God-awful ergonomics of the Aleph 3 power amplifier, and the
potentially troubling foible of the volume control in the Aleph L preamp, I'm keeping the
pair. They are replacing my much-loved Levinsons as the ones to beat— they are that
good. Because of their engaging qualities, and their absolute performance, I am willing to
tolerate the above-mentioned faults.
So: Have I succumbed to the current, trendy, or fashionable single-ended silliness, or
have I just become single-endedly sane?
Aleph 3: Quality: 4 Stars Value: 3 Stars
Aleph L: Quality: 3 ½ Stars Value: 2 Stars |
