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Bel Canto REF600M Mono Power Amplifi er ON TEST
Readers interested in a full technical
appraisal of the performance of the
Bel Canto REF600M should continue
on and read the LABORATORY
REPORT published on page 34.
Readers should note that the results
mentioned in the report,tabulated
in performance charts and/or
displayed using graphs and/
or photographs should be
construed as applying only to
the specific sample tested.Lab Report on page 34
LAB REPORT
BEL CANTO REF600M
MONO POWER AMPLIFIERBrand:Bel Canto
Model:REF600M
Category:Mono Power Amplifier
RRP:$3,990 each
Warranty:One Year
Distributor:Absolute Hi End
Address:PO Box 370
Ormond VIC 3204
(04) 8877 7999
[email protected]
http://www.absolutehiend.comt Power, power, power
t Form factor
t Sound qualityt Standby modeIn the centre of the front panel, as you
can see from our photograph, is an expanse
of dark Perspex, behind which is a single
green LED. As you’ve probably guessed, the
Perspex is there to keep the ‘look’ of the
product the same, so you can match the
REF600M (or, rather, REFM600s) with other
of Bel Canto’s e.One Series products, such
as a DAC, or a CD Transport, or a Network
product, all of which do have displays hidden
behind their Perspex panelling.
The rear panel has both balanced (via
XLR) and unbalanced (via RCA) inputs,
which must be switch-selected via
a pushbutton.
The speaker terminals are WBT ‘Next-Gen’
types. A large power switch that operates
horizontally (so no American/Australian/Brit-
ish arguments about whether off should be
‘up’ or ‘down’ then!) is positioned at the left
of the rear panel, above a standard three-pin
IEC 240V mains socket. The only other fea-
ture on the rear panel is a single d.c. trigger
input, so that the REF600M can be remotely
switched in and out of standby mode. (When
the REF600M sees a d.c. voltage of between 5
and 12 volts at the trigger input, it will cease
amplifying, turn off the front-panel LED and
put itself into a low-power standby mode.
Remove the voltage and it switches out of
standby.)
CIRCUITRY
Internally, the Bel Canto REF600M starts with
a custom, fully-balanced input/driver stage
designed by Stronczer himself to have very
high common-mode rejection. According to
Bel Canto, this circuit (which it calls an ‘Im-
pedance Optimized Input’) is critical to the
amplifi er’s performance, with Stronczer say-
ing: ‘it ensures that the refi ned dynamic qualities
of the recording are preserved.’ This circuit drives
a Class-D nCore NC500 output stage devel-
oped by famous Dutch manufacturer Hypex.
Everything is powered by an NC1200/700
switch-mode power supply, also developed
by Hypex. Stronczer obviously believe in
re-inventing the wheel, nor does he appear
to have a problem with ‘not invented here’
circuitry. In the past he’s also used Class-D
modules from Bang & Olfusen (so-called ‘ICE-
power’ modules) as well as Class D modules
from Tripath, along with switch-mode power
supplies sourced from other SMPS specialist
manufacturers.IN USE AND LISTENING
SESSIONS
Because there is no physical stand-by power
switch on the REF600M, and you have two of
them, switching them on and off manually
via the mains power switches on the rear isn’t
very practical, so I’d suggest any equipment
you use with the REF600M should have a
5/12V d.c. trigger, so you can use the circuit
provided. The speaker terminals are WBT’s
SBT-0703 types (mostly made of plastic),
which Stronczer said he uses ‘because they
impart minimal sonic signature to the sound,
remaining open and grain-free up throughout the
audio frequency band.’ I have to say I am not
a big fan of this particular WBT Next-Gen
terminal, because I personally fi nd it a bit fi d-
dly to get a good connection when using bare
wire, because there’s not a lot of metal in the
design. However, it does work really well if
your speaker wires are terminated with either
spade connectors or banana plugs,
in which case you’ll achieve the de-
signed contact resistance of less than
0.14mΩ. (Note, too, that becauseWBT makes eighteen completely different
types of ‘NextGen’ speaker terminal, most of
them completely different from each other,
the word ‘NextGen’ is hardly a descriptor
of the terminal type.) Because the REF600M
amplifi ers are Class-D, they never get more
than ‘barely warm’ no matter how hard you
push them, so placement and ventilation are
not issues: you can stack them, place them
sideways, hide them in a drawer... basically,
you can put them anywhere you want!
OMG! How powerful are these new ampli-
fi ers? Enormously, overwhelmingly power-.EWPORT 4EST ,ABS0OWER /UTPUT INTO
OHM
OHM AND
OHM
NON
INDUCTIVE LOADS AT (Z K(Z AND
K(Z ;"EL #ANTO - -ONO 0OWER !MP=OMG! How powerful are these new Bel Canto REF600M
amplifi ers? Enormously, overwhelmingly powerful is the
answer, and it’s instantaneous, super-clean power...