32 Australian
ON TEST Bel Canto REF600M Mono Power Amplifi er
LAB REPORT ON PAGE 34ful is the answer, and it’s instantaneous,
super-clean power that is available from the
instant you turn on the amplifi er—no warm-
up time required here! That means that the
Bel Canto REF600Ms were able to drive my
most power-hungry speakers which, with
a measured sensitivity of just 81dBSPL, are
ludicrously ineffi cient, to volume levels that
were ‘way more than anyone is going to
need in a domestic situation.
Equally important, even though the am-
plifi ers were working moderately hard just
to deliver ‘average’ sound pressure levels due
to the ineffi ciency of the loudspeakers, there
was no sense of compression or clouding of
the sound, and no distortion that I could
hear. Musical transients were delivered with
immediacy, clearly rising above the music
and punching through in a manner entirely
consistent with the musical programme.
Because of this I was able to joyously
crank up the volume on Coldplay’s latest,
‘A Head Full of Dreams’. If you cooled on
Coldplay after the ‘Ghost Stories’ and ‘Vive
La Vida ...’ albums, it’s time to pony-up and
buy what I reckon is Coldplay’s best album
ever. Sure you’ll hear it’s eclectic, but it’s
all up-beat, and with pop such as Birds (an
absolute stand-out), and tracks that mash
R&B, soft rock and head-bangers, plus guest
artists including the likes of Beyoncé and
Noel Gallagher, totally exciting.
There are a few naff moments, one such
being the heartbeat-like bass line Berryman
plays on Adventure of a Lifetime just after
Martin has sung the line ‘I feel my heart
beating’ and some might say the album is a
tad ‘manufactured’ or ‘calculated’, but that
hasn’t stopped me playing it continuously
ever since it was released.Aware that in the past some Class-D ampli-
fi ers have turned out to be relatively load-
sensitive, I thought I’d put the REF600Ms to
the test by wiring up a second pair of speakers
in parallel, effectively dropping the overall
load impedance below 4Ω and reaching very
close to 2Ω in the upper bass region, where
there’s a lot of musical energy. The second pair
of speakers I then isolated in another room,
so I could hear only the main speakers. I was
pleased to hear the sound from those main
speakers was unchanged: the new demanding
speaker environment in which the REF600Ms
found themselves didn’t faze them one iota.
I was still able to drive the speakers as loud as
I dared (the REF600Ms could obviously have
provided more power... it was the speak-
ers’ power-handling capacity that was the
limiting factor here) and not only was the
tonal balance completely unaffected, with the
relationships between the volume of the bass,
midrange and treble identical, but also there
was no increase in distortion... or rather, since
I couldn’t hear any amp-related distortion in
either set-up in the fi rst place, the REF600Ms
continued to not have any audible distortion.
I checked for the purity of the sound
using the Ensemble La Reverdie’s beautifully-
recorded album ‘Musica Antiqua’, which
traces the heritage of Celtic womanhood in
the Middle Ages. It’s a very revealing disc soni-
cally, not least because it’s naturally recorded
in a natural acoustic without any compression
or equalisation, but also because it features(some) easy-to-source instruments (C descant,
G treble and C tenor recorders) for ready tonal
comparisons. Then there are the clear voices
of sisters Claudia and Livia Caffagni and Ella
and Elisabetta de’ Mircovich, and (also sisters,
but Ella is no longer with the ensemble, hav-
ing been replaced by cornettist Doron David
Sherwin).
When a voice was solo, I was always able to
tell which of the four women was singing, and
when two sisters were singing, the REF600M’s
clarity was such that the almost-similar voices
were kept as separate entities, rather than
melding together, yet while maintaining the
intended musical effect.
The acoustic of the venue, the slow pace
of the singing and the clarity of the record-
ing allowed a kind of ‘music vivisection’ that
highlighted all the Bel Canto’s many musical
strengths, including one I have not mentioned
so far, which is how noiseless the amplifi er is...
so quiet that I could ‘hear’ the ambience of the
recording venue, and so quiet that on record-
ings where ‘digital black’ had been engineered
between the tracks, I could not hear anything
at all in the listening room, save for my own
breathing.CONCLUSION
Enormously powerful, very quiet and with
a sound quality so tonally accurate that it’s
a constant delight to the ears, Bel Canto’s
REF600M is an outstandingly good power
amplifi er. Frank WrightEnormously powerful, very quiet and with a sound
quality so tonally accurate that it’s a constant delight to
the ears ... an outstandingly good power amplifi er