November 1, 2009
Behold APU768 Preamplifier-Processor-DAC
The precursor to the Behold APU768 could well be thought of
as the Audio Suite modular preamplifier, introduced in 1985 by Cello, now defunct. You
could configure the Audio Suite with a phono input, various line-level inputs, and
balanced and/or unbalanced outputs, and it had a separate power supply. In terms of
functionality options it was a product ahead of its time, and used units still seem to
command higher-than-average prices when they show up on eBay. The Audio Suite was also
outrageously expensive for the era in which it was introduced, costing well into five
figures, depending on which options were included -- back in the early 1980s, not much of
anything in the high end was as costly as the Suite. But those who owned an Audio Suite
swore that the flexibility it offered and the quality of sound it produced were worth the
exalted price. Some still feel that way about it today.
The Behold APU768 shares many similarities with the Cello
Audio Suite, at least in terms of being modular, offering many different functions
depending on its configuration, and being expensive when considered against almost
everything else it competes with ($58,000 USD as configured for the review). Like the
Audio Suite, it is also well ahead of its time; if my experience with it proves any
indication, the Behold, too, might be considered a classic 20 years after its launch. But
the question I asked myself was whether the APU768 is the harbinger of preamplifiers to
come. Perhaps the answer is yes, but other electronics manufacturers will have to climb a
steep learning curve before being able to produce such a technically advanced component.
A 2009 version of the Cello Audio Suite? Lets explore
it.
Modular design, advanced functionality
Behold is a German firm that produces a line of electronics
-- power amps, a DAC, a CD player, an integrated amp, etc. -- that is quite innovative in
terms of technical capability. Chief designer Ralf Ballmann, an extremely opinionated
engineer, has some very pointed ideas about how an audio system should be designed and
implemented. Ballmann did not start his engineering career in high-end audio, but began by
designing network analyzers. He found a home in our field when he realized that his
training could help him innovate in what he considers some critical technical areas of
high-end audio.
Before beginning the design process for his Behold
electronics, Ballmann examined several of the leading electronics products that were
available, and wasnt impressed by what he saw and heard -- he knew he could do
better. What he came up with was way outside the box. For instance, in a full Behold
system (sans loudspeakers and speaker cables), the digital-to-analog conversion is
performed not in the source component, or even in the processing unit or separate DAC, but
in the power amplifier -- the last stage before the signal is amplified and sent on to the
speakers. Ballmann contends that the signal should be kept digital for as long as
possible. The APU768 reviewed here was auditioned in The Worlds Best Audio System
2009, in this type of system model. I also used it in my reference audio system, where it
performed D/A conversion.
Each APU768 ($30,000 base price) is configured and built to
order with any number of optional modules that will equip it for any number of functions.
A single APU768 can accommodate 14 of these modules, mixed and matched in virtually any
configuration; the unit I reviewed was assembled for stereo operation, but the APU768 can
also be configured to anchor a multichannel audio system. Some of the more obvious choices
of modules were included in my unit: the ODI768 ($3500) module, with eight digital inputs,
four S/PDIF on RCA jacks, and four TosLink; the ADC192 ($5000), with four analog stereo
inputs (these can also be configured as multichannel inputs), contains an A/D converter
(all analog signals are converted to digital; there is no analog pass-through); the
DIO768, with three digital inputs and three digital outputs; the DAC192 ($4500), with an
internal D/A converter and the requisite stereo analog outputs on RCA and XLR jacks
(multiples of these modules can be used for multichannel operation); and the APD192
($15,000), which includes Ascendo-derived room-correction software (see below).
The rear of the APU768 is built on a card-and-slot
architecture: essentially, you remove the top panel of the unit, carefully insert each
module into the digital bus system, replace the top panel, and secure the module to the
unit by screwing its aluminum-plate rear housing to the frame of the APU768. If you order
an APU768, it will of course come already fully loaded and configured for you. But if your
needs change over time, modules can be shipped to your dealer and this process can be
completed in the field.
The physical construction and layout of the APU768 are as
impressive as high-end audio gets. The all-aluminum chassis feels like a brick when
lifted, and the rather sparsely populated faceplate belies the sophistication lurking
behind it. The largest rotary control, at the right side of the faceplate, allows the user
to turn the APU768 on and off by shallowly depressing the knob. This knob also controls
the volume. The knob at the left end of the faceplate allows the user to navigate, select,
and activate items in the extensive menu system. A large LCD screen displays the menu
system, volume readout, and input selection, is easily read from across the room, and can
be customized to display varying levels of information to suit the users needs.
Immediately to the right of the display is the third knob, which can be used to control
other Behold components, such as their CD player. The APU768s small, rectangular,
external power supply can be located away from the main unit and connects to it with a
twist-lock-terminated power cord. The supply can then be connected to the wall with your
own power cord via the IEC input jack.
The Beholds room-correction system is quite advanced,
and its setup and use are more complex and encompassing than any Ive seen. The
software itself was developed by Jürgen Scheuring of Germanys Ascendo, manufacturers of some highly
regarded loudspeaker systems. Partially funded by a government grant to study room
acoustics, Ascendo has developed a room-correction system that uses advanced programming
and a professional-style user interface to accomplish its mission. When you order an
APU768, the dealer will come to your house with a laptop fitted with Ascendos Room
Tools software, which interfaces with the APU768. A microphone then connects to the
laptop, and the computer is connected to the APU768 via an Ethernet cable. With the
microphone in the listening position, a series of measurements is then taken, using
built-in test tones. Readouts on the laptops screen show the left- and right-channel
frequency responses.
Other measurements are also available, and these will be
used in the setup as well; my description here is greatly simplified to give you just a
feel for how it all works; detailing everything the system will do requires a
manual unto itself. In a nutshell, the room-correction system can be used in two ways: It
can address nonlinearities in your systems frequency response through its
automatic-correction function, and with it you can create custom frequency-response
curves to suit your listening tastes, room, and speakers. The included remote control lets
you scroll through four saved FR curves and turn the correction software on and off, so
that you can easily do A/B comparisons on the fly to hear what effect the software is
having.
The corrected frequency response in my Music Vault
listening room with the Rockport Technologies Arrakis loudspeakers.
Sound and use
Because of the varying nature of a modular component, the
Behold APU768s sound will entirely depend on how it is configured and in what system
context its used. It can be used as a simple preamplifier, albeit with A/D and D/A
stages, but that is the least likely use for such a multidimensional product. Far more
logical, in what I would figure would be the simplest system it would be used in, is to
use an APU768 as a preamplifier and DAC, which is what I did through much of the
review period. I also added the Ascendo room-correction feature, and Ill note how
that performed as well. I didnt cross over my speakers using the active crossover
functionality, which would have required multiple power amplifiers and a speaker system
specifically set up for active drive.
I fed the APU768 only digital signals, mainly S/PDIF from
my Apple MacBook laptop. I dont know how transparent the ADC section is because my
unit didnt include that module. Most audiophiles consider it anathema to convert to
digital a pristine analog signal from a phono or CD source or a computer-served DAC, only
to then reconvert that signal to analog. But after giving this a lot of thought, Ive
realized that a case can be made for it, at least in one situation: where the user has
some severe room-related frequency-response problems that can be solved only with
electronic correction. Ive long been of the opinion that tonal balance is very
important to how we perceive sound quality, and that the most pronounced differences heard
among high-end audio systems can be accounted for by deviations from flat frequency
response. Most speakers dont measure all that flat in an anechoic chamber, and
things get only worse when theyre placed in actual listening rooms; in most cases,
there will be significant shifts in tonality due simply to the room-loudspeaker interface.
Nonlinear bass is one of the worst offenders, but depressions and otherwise ragged
behavior throughout the audioband can be enough to make even really good components sound
horrible.
I found the Ascendo-derived room-correction system a
marvel. The APU768 provided some mild equalization that brought down a slight emphasis in
the midband, smoothed some peakiness in the bass, and partially filled in one depression I
had at around 80Hz. The overall sound, with equalization courtesy the APU768, was now
fuller in the lower registers and more neutral in the midrange, bringing male voices, for
instance, in line with what I heard higher in the audioband. Neil Youngs Live at
Massey Hall 1971 (CD, Reprise/WEA 43328) was rendered with Youngs voice
displaying just the right amount of presence but without sounding too forward. His guitar
was crisp and clean -- I heard no hint of electronic haze or grit.
I put one listener through a quick A/B test, with and
without room correction. He preferred the sound without room correction, stating that he
heard a slightly compressed soundstage with it on. I felt that the soundstage wasnt
really compressed, but that the tonal balance of the system was on a more even keel, with
no individual elements jumping out at me. We might actually have been hearing
approximately or exactly the same things, while bringing to the experience our different
tastes in sound.
There was no question that the bass range was extremely
linear with the room-correction software employed. Acoustically, the Music Vault is a
fairly neutral environment. But as in any room, there are dimension-related bass modes --
peaks and dips in the frequency response -- that must be addressed acoustically or
electronically. The APU768 was able to improve areas that Ive been unable to address
with passive bass traps -- the traps designed to absorb frequencies under 80Hz or so are
way too large for the Vault. More linear bass, coupled with the bass articulation and
power of which the Rockport Arrakis loudspeakers are capable, yielded the best bass
Ive yet heard in my room. Bass instruments were as nimble as ballerinas when they
needed to be, yet were utterly controlled with massive power when that was called for.
Room-related artifacts ceased to be problems, leaving only clean and articulate yet deep
and powerful bass.
One example was the drums from one of my reference bass
tracks, "Norbu," from Bruno Coulaiss music for the film Himalaya
(CD, Virgin France 848478). This is an instance where the room can quickly overwhelm the
sound produced by the speakers. When the massive drums are struck, the bass energy is
sustained, deep, and powerful. The room can resonate wildly, swamping the output from the
speakers and obscuring details within the music. With the room correction off, the subtle
trailing decay as each thwack rolled into the next sounded somewhat one-note-like,
the room ambience in the recording hidden by the bloat in my room. With the bass response
more linear, I could hear farther into the recording space, and more minute details within
a larger soundstage. This greatly affected my enjoyment of this track: Instead of sitting
there wondering how much my room was influencing what I was hearing, I was confident I was
hearing only the instrument and the space of the recording venue, and that heightened my
sense of musical involvement.
As an example of just how real my system sounded with the
APU768 at the helm, I recall a day in February, when fellow writer Randall Smith and I
were setting up The Worlds Best Audio System 2009. My wife was downstairs in our
living room when she heard the system come on. We were playing Neil Youngs
"Helpless," from his Live at Massey Hall 1971. It begins with only
Youngs guitar, and Andrea bolted upstairs to see what was happening -- such was the
transparency, tonal correctness, and overall real nature of what was being played
that she thought one of us was actually playing a guitar in the Music Vault. She was
amazed to find that it was TWBAS 2009 playing back that guitar, and said that shed
never before heard anything as real-sounding coming out of the Vault: "As real as
Ive ever heard from a stereo," she called it. It was an astute observation,
quickly and honestly arrived at. I would eventually come to the same conclusion, but being
an audiophile, it took me a little longer. Imagine that.
As a pure preamp-DAC, the APU768 was as transparent as any
combination of products Ive ever used. I could go down the list of preamplifiers and
sources Ive used in the past and how it compared with each, but Ive not used
any combination of them that was better than the Behold. It was, essentially, dead
neutral.
That poses a conundrum for someone in my position. I get
e-mail -- lots of it. More often than not, these e-mails are from readers who want buying
advice about particular components that I have some experience with. When considering my
answer, I often think, Would I buy it if I were this person? I let my answer guide
my response. In the case of the APU768, formulating responses to such questions will take
a bit more consideration. In my case, I couldnt buy the APU768 because it would
complicate my life as a reviewer. I need to be able to switch among separates -- DACs,
preamps, room-correction devices, etc. -- so that I can evaluate them individually. The
APU768 would take away that flexibility and make it impossible for me to do my job.
However, if I were not a reviewer, the APU768 would simplify things completely, and
give me state-of-the-art performance in all three of those product genres. Im not
going to insult anyones intelligence and talk about saving money on interconnects by
having an all-in-one component like the APU768, which costs $58,000 -- those in a position
to purchase the APU768 arent concerned with pinching pennies! But the reality is
what it is: Performance-wise, the APU stands up -- and then some -- to its exalted price.
Its world-class as a preamp and as a DAC, and when you add its other features, it is
the sole occupant of its category.
Conclusion
The Behold APU768 is a rarity: a unique component in a
high-end marketplace that has far more me-too products than most journalists care to
admit. It doesnt use an off-the-shelf software platform from another maker, and
there arent really any less-expensive alternatives that offer exactly what it will
give you. Although you could easily think of the APU768 as a preamplifier that combines
DAC and room-correction functionality (and an active crossover, and a multichannel
controller, and . . .), the whole is far more valuable than simply adding up the number of
boxes it could replace in your listening room. Add to that its vault-like construction,
and youre faced with a machine that is uniquely configured and built.
All that would be for naught if the APU768 didnt
sound like a million bucks -- or at least like $58,000. I cant put an exact price
tag on it -- if I said it sounded like $57,000, would that mean it had failed? But I can
confidently state that the APU768 should be considered a first stop for those lucky few
who can afford to assemble a state-of-the-art audio system. It can work wonders, and it
wont be outclassed by any other single component in the equation. The Behold
APU768 is the most advanced piece of high-end electronics Ive ever used.
. . . Jeff Fritz
jeff@ultraaudio.com
Model: Behold APU768 Preamplifier-Processor-DAC
Price: $58,000 USD as configured ($30,000 base price).
Warranty: Five years parts and labor.
Behold
Theaterplatz 14
D-91054 Erlangen, Germany
Phone +49 9131-503700
E-mail: sales@behold.eu
Website: www.behold.eu
US distributor:
Laufer Teknik
27 Whitehall Street, 3rd Floor
New York, NY 10004
Phone: (212) 269-6384
E-mail: slaufer@lauferteknik.com
Website: www.lauferteknik.com
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