Separation Anxiety
AFTER
posting my review of the Monarchy Audio SM-70 power amplifier in the november/december
issue of Planet HiFi, I received an email from the ever-enthusiastic C.C.
Poon, President and Chief Designer of Monarchy Audio. I suspected that
Mr. Poon had finished reading my review and was contacting me to provide
his feedback regarding my observations of his little zero feedback amplifier
design. Yes, his impressions were there in Outlook, conveying his thoughts
through my screen. But he knows audiophiles and their passion for seeking
out ‘even-better’ sound. And so, with a few well-placed words, he managed
to lure me into taking on a second SM-70 amplifier and use both units in
my system in bridged mono mode. I felt a bit suckered, but the thought
of possibly juicing more power out of the 25 watt SM-70 was enough for
me to clear out some room on my equipment rack and check the package room
three times a day.
In stereo configuration,
the SM-70 is rated at 25 watts/channel. But as I had mentioned earlier,
the SM-70 can be bridged and used as a mono amp for powering a single loudspeaker.
There are a couple of advantages to bridging the SM-70. The most obvious
benefit lies with the increase in power output, with the SM-70 jumping
from 25 to 75 watts/channel as we flip a switch and move from stereo to
mono. The only real significant drawback of the SM-70 is the amplifier’s
power rating (The introduction of the SM-70 Pro addresses this need - ed).
While the unit did have good control of my Energy Veritas v1.8 and later
on, the Merlin VSM Millenium loudspeakers, they stumbled at higher listening
volumes. And I suspect that when used in a large listening room, they would
really begin to show some reservations. I found smaller bookshelf type
loudspeakers, such as my Silverline Audio SR-12 to work best with the SM-70.
Sound really blossomed on the SR-12, with the SM-70 driving them to very
high SPL’s without ever skipping a beat. Now, with 75 watts/channel and
increased current capabilities, the SM-70 should find the number of suitable
loudspeakers to have increased dramatically. In addition to greater power,
two mono SM-70’s may provide better isolation between channels. I do not
know if this is founded or not, but I have read that by physically separating
the left and right channels, one’s system could receive quieter operation,
resulting in a lower noise floor, among other things. In a few moments,
we’ll see if this holds true.
The rear of the
SM-70 sports both dual RCA jacks and a single XLR balanced input. Above
this lies a toggle switch that allows the owner to change the amp from
stereo operation (switch down) to mono operation (switch up). Although
Monarchy Audio recommends using the balanced XLR connection, a user can
flip the switch to mono and utilize the single-ended RCA input if he or
she chooses. They just need to make certain to use Input A only on both
the left and right amplifier.
To test the sonics
of the Monarchy Audio SM-70 in bridged mono, I ran the pre-out from my
Jeff Rowland Concentra integrated amplifier to the amplifiers or used my
McCormack Micro preamplifier in both active and passive mode. Source remained
the Meridian 586/Birdland Audio Odeon-lite DAC, cables were Cardas Neutral
Reference all-around, and loudspeakers were either the awesome Merlin VSM
Millenium or the Silverline Audio SR12. Clean power was provided by Silver
Audio Powerburst AC power cords and a Chang Lightspeed CLS 3200 ISO MKII.
New Sound
After letting my
system ease in with a single SM-70, I switched in a second SM-70, made
the necessary cable adjustments on the rear of the amps, and flipped up
the toggle switch to kick in mono configuration. Even though I was crouched
slightly behind the loudspeakers, I could hear that the sound had somewhat
improved – more lively, open, and generally more pleasing to my ears. But
I could not determine the specifics of the improvements because I was in
a less than ideal position. Moving my way towards the sweet spot on my
sofa helped me to flesh out the improvements and more clearly define what
was happening to the sound of my system.
The second SM-70
increased dynamics, drive, rhythm and the pace of music. These sonic improvements
were the first things that hit me as I played Earl Klugh’s
Living Inside
Your Love. Electric bass became energized with increased slap and slam.
Bass notes were more delineated, helping each finger pluck to sound more
precise and slightly cleaner. Attack was now etched into the soundscape.
There was no hesitation or pause to the music, as each bass note contrasted
easily against the musical background.
I also heard a
bit more openness to the sound, as instruments and voices moved both forward
and outside the physical boundaries of the loudspeakers. There were less
restrictions on the music. To my ears, the walls of my listening room appeared
to either move away from each other or become more transparent to the sound.
In either case, I believed that the music further transcended the concrete
barriers that are enclosing my listening room.
The second SM-70
amplifier acted like a musical injection of helium, significantly expanding
the soundstage. On “Sputnik”, from Lou Donaldson’s Lou Takes Off
(DAD 1026), the musicians take on newfound freedom and move around the
stage as if un-tethered. Donald Bird’s trumpet appears far stage left and
Art Taylor’s drum kit explodes with rhythm behind my right loudspeaker.
Everything just sounds bigger and more three-dimensional.
High frequencies
also improved, but only slightly. They became more extended but only on
certain, very well recorded tracks. I also witnessed a reduction in ‘tizziness’
on a few of my favorite albums, especially on high hats and cymbal crashes.
But, again, the improvement was very small.
Conclusion
In the case of
the Monarchy Audio SM-70, two are definitely better than one. Running a
pair of SM-70 amplifiers in bridged mono configuration resulted in audibly
significant improvements over the already stellar sound of a SM-70 in stereo
mode. The sonic gains consist of improved dynamics and rhythmic drive,
three-dimensionality, clarity (and simultaneously, smoothness), attack,
and high frequency reach. When I look at this list of benefits, I cannot
believe that I do not have any caveats to balance them out. But, that’s
because adding a second SM-70 to your system will result in nothing but
improvements to your system’s sound.
Now, you’re probably
saying, “Is that it?Just go out and buy another one?”Well, yes and no.
Two SM-70’s will buy you better sound and more flexibility when matching
them with larger and/or lower impedance loudspeakers. But, you’ve still
got to shell out another $719.00. In my opinion, it is well worth the extra
investment, even if you have to buy just one right now and upgrade to two
in the near future. But, I can only make a recommendation, one that you,
as a reader can accept or discard. So, as we go to print with this review,
I’m rolling change as fast as I can without getting severe paper cuts.
I should have the 700 clams by Christmas, sooner if I start collecting
cans and taking donations. If you’re interested in helping out a fellow
audiophile in need, please send cash to my attention at our main office.
Thanks.
GREG's
SYSTEM:
Main:
Meridian 586 CD/DVD player >> Luminous
Audio Allegro coaxial digital interconnect >> Birdland Audio Odeon-lite
D/A Converter >> Cardas Neutral Reference single-ended interconnect >>
Jeff Rowland Design Group Concentra integrated amplifier >> Cardas Neutral
Reference speaker cable >> Energy Veritas v1.8 / Silverline Audio Panatella
mkII loudspeakers
Secondary:
Pioneer DV-525 CD/DVD player >>
Monster Cable M-1000D coaxial digital interconnect >> Birdland Audio Odeon-lite
D/A Converter >> WireWorld Atlantis II/Luminous Audio Monarchy Signature
single-ended interconnect >> Decware SE84B amplifier >> JPS Labs Ultra
Conductor speaker cable >> Silverline Audio SR12 loudspeakers/Osiris speaker
stands
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