|
A class D amp is a switching amplifier.
Such amps have several advantages, not the least of which is their
efficiency, which allows them to run much cooler than traditional high
power amps. My Nemos are a class A design, which runs very warm. During
summer, my listening room needs extra air conditioning, while in winter
I need to periodically open up windows and doors to cool the room down.
Not so with a switching amp like the Rotel 1092. It can be placed in a
cabinet without worrying about overheating. A switching amplifier
doesn’t need massive heat sinks and can use a smaller and cheaper power
transformer. The 1092 never got more than mildly warm, even when run a
high output.
Historically, the
biggest drawback of switching amps related to the power supply from the
wall. A very clean and dependable power supply is a must, or you risk
getting distortion and other noise. My main system has three dedicated
power supplies, and I had a variety of “conditioning” power cords to
experiment with. I did not use a conditioner for the amp (I have always
felt that pace, rhythm and timing suffer whenever I insert a power
conditioner between the wall outlet and high power amps) and I
experienced no power supply problems. I don’t know whether this had
anything to do with the Rotel 1092’s design. Rotel’s implementation of a
switching amp makes use of the highly-praised Bang & Olufsen ICEpower
power modules, and if the 1092 is any indication, we’re going to be
seeing many products incorporating these modules.
LET'S GIVE THIS GUY A SHOT IN THE MINORS
One thing I’ve thought about doing with
some of the amps I get to review is to plug them into one of my midfi
systems. The preamps I use in both systems have pre outs, which let me
bypass the amplifier section and instead route the signal through an
external power amp. However, this is not exactly easy to do when you are
testing monoblocks that weigh 100 or more pounds each, so I rarely do
it. Enter the Rotel 1092. At 22 pounds, I had no transportation problem,
so the 1092 went right into the basement system. This particular
preamp is rated at 120 wpc, and has generally served me well. It
sounds reasonably good to the non-critical listener and produces a
pretty solid bass line.
When I inserted the
Rotel 1092 the whole room came alive. Not only did the usual benefits of
more power surface (bass and dynamics), but the soundstage expanded in
width and depth. Cursory listening also revealed greater detail and
extension without harshness. These effects were not subtle. They were a
huge improvement in every aspect of this modest system. “OK” I thought,
“You’ve made the first cut. Let’s go play with the big boys.” I took the
1092 to my dedicated listening room.
WELCOME TO THE BIG LEAGUES |
|
I started out by simply placing the
Rotel 1092 on an amp stand. I initially made no attempt to address
vibration or use alternate power cords. I just wanted to hear what the
1092 could do driving my B&W 800Ds. The 800D’s love power – the more
power you feed them, the better they sound. To illustrate how much
power: I sold my Mark Levinson 336 (350/700/1400 wpc into 8/4/2 ohms)
and bought the Nemos (600/1200/2400 wpc into 8/4/2 ohms) because, among
other things, the extra power clearly benefited the 800Ds.
I knew that I should expect a big sound
to come out of this “little” amp, but I was still startled when the
800Ds began cranking out Talking Heads. Plenty of energy, with the
feeling of lots of headroom. A very good soundstage, with precise
placement of individual performers. A bit edgy, but what did I expect
using a stock power cord?
I next put BDR cones and pucks under
the 1092 and substituted the ZCable Cyclone for the stock cord. (I
actually worried that the Cyclone would lift the Rotel 1092 off of the
cones.) I then placed some weights (yes, weights used in weightlifting)
on the top of the 1092 to add mass. When I started the Talking Heads
disc again I could immediately hear more smoothness and bottom end.
“This is going to be interesting…” I thought. I then decided to let this
recipe simmer for a few days before really tasting it and went to bed –
then to work – then to bed – and then it was the weekend.
Two days later I sat down for some
serious listening. Over the next several days I played a wide variety of
music: rock, small combo jazz, classical, mamba, big band (sorry – no
rap). Rather than keep you in suspense, here is what I heard:
-
A wide soundstage that was only a
foot or two narrower than that produced by the Nemos (my room width
is 32 feet, and the Nemos fill it);
-
Mid range and treble detail that
came respectably close to the M-2000;
-
Clear placement of performers that
was not quite that produced by the Nemos and M-2000s, but really
very good; and
-
A generally smooth presentation.
The Rotel 1092 could not replicate the
sheer bass weight of the Nemos (something the Nemos excel in) or the
explosive dynamics of the M-2000. Moreover, the 1092 is not as smooth as
the Nemo on acoustic material. These differences are only to be
expected. My Nemos are tweaked to the hilt with Walker reference
Prologue Amp Stands and Walker Valid points and tuning discs, and each
monoblock has its own dedicated power supply. The Rotel 1092 had one
cord to draw power for both of its channels (although each circuit is a
20 amp circuit).
It’s fair to say that the Rotel 1092
was 85% of the Nemos and the M-2000s. Each audiophile quality was
well-represented. Detail, depth, stage width, instrument placement,
dynamics, PRAT were all consistently good. Its smoothness was a
particular surprise, since I expected (I’m not sure why) something more
strident. However, having said that, I think most listeners would prefer
the Rotel 1092 with speakers that do not exaggerate the top end. I do
not think that the 1092 would have sounded as good with my older B&W
Nautilus 802s (without the Diamond tweeter), which were not as smooth as
the 800Ds. The 802s (the pre Diamond tweeter version) were speakers you
had to work with, and it was difficult to coax really good
multi-textured vocals out of them, so the other components (such as the
amp) had to make up for that shortcoming. The 1092 probably would not
have been the best choice to do that.
I would also say that the Rotel sounds
best with energetic music. It seems to help propel that type of music
along, making you want to tap your toes. In fact, if you are a rock
aficionado, it’s hard to find comparable value in a stereo amp. It made
me wonder what the Rotel 1092 could do in an integrated music/home
theater system….
A MOVIE WOULD BE NICE |
Though this was primarily a 2-channel
review, I couldn’t help trying the Rotel 1092 in my home theater. Not to
discourage you from trying the 1092 in a 2-channel system, but I
concluded that a combination of a few 1092s and 1091s would make a
really terrific surround system for movies. I only had one stereo amp to
work with, but I liked it as much or more than my old proceed HPA3, and
if the 1092 and 1091 had been an option for me in 2000 I would have
chosen them over an HPA2 and HPA3 system. Moreover, the 1092 and 1091
are easy to install in a system where (unlike my main listening room)
you don’t want exposed wires and equipment strewn about the place. They
can go in a cabinet with other components and produce a really great
integrated 2-channel/home theater system.
CONCLUSION
Nice job Rotel!
You’ve created a high value component that can be easily used in a
2-channel or home theater application. Paired with the right speakers
and cables it will make beautiful music, especially with dynamic and
energetic music. Definitely recommended.
(See below for a ”regular-guy”take on
the 1092 by Jeff Heuel, a neighbor of mine. I gave him the Rotel 1092 to
try for a week. Here are his comments.)
ROTEL RB-1092
When this unit arrived, I was in the
process of converting my listening area from a 5-channel music/movie
room into a 2-channel music only room. I decided to run this amplifier
from the preamp outputs of my surround receiver. Out of the box, the
size and simplicity of the RB-1092 disguised the strength of the power
within. I was impressed from the start with the high quality dual
binding posts that enabled true bi-wire speaker setup. After the
straightforward pre-amp and supplied power cord connections, I was ready
to go.
The first thing that struck me when I
powered up this amp was the increased width and depth of the soundstage.
The instruments and vocals were very distinctly placed. My immediate
inclination of course was to see what all that power could do. So I put
on my brand new 200 gram pressing of Led Zepplin One. I began nudging
the volume control higher and higher into ranges that I previously never
considered. The result? It seemed that no matter how far I pushed it,
the sound became clearer and more focused without an inkling of
distortion. I only backed off after becoming concerned about alarming
the neighbors.
So, I thought, that’s what you can do
with 500 watts per channel - perfect for our next block party. Funny
thing is, though, this baby had just begun to reveal itself to me. As I
began to burn in the unit at more modest volume levels for a more
detailed evaluation, the real effect of that power struck me. I would be
listening while reading and find myself suddenly hooked and reeled into
the music. The level of detail I was hearing was incredible. Nuance in
recordings I had listened to hundreds of times revealed themselves. From
Patricia Barber to Valerie Carte to Little Feat, the result was the
same. Especially noteworthy was the way vocals, percussion, and acoustic
guitar jumped put of my system and commanded my attention. I couldn’t
get enough. I listened for hours on end, cursing the fact that I had to
go to bed.
After some time I did begin to notice a
bit of softness in the mid-range, but I attributed this more to the
brightness of my speakers. A simple upgrade in the power cable remedied
this as well as tightening up the bass. The more I listened, the more I
understood what power is really for: the amp does all the work to bring
out the subtle detail in all music at all levels.
I had a notion of
going toward all low power tube in reconfiguring my listening set up,
but this experience has caused me to rethink my approach. I wonder how
this amp would sound with a tube front end… |
