Finland’s Mad Professor has always found
favor with front-line tone obsessives like
Marc Ford and Pete Anderson by building
more than simple clones. Instead of following
trends, the company has built pedals
that capitalized on subtle differences
and less-explored formulas—particularly in
the realm of overdrive.
The Stone Grey, however, is Mad
Professor’s path of entry into the world
of modern high-gain and heavy distortion.
Björn Juhl and his team designed
the Stone Grey to dish out gobs of gain
with ultimate clarity and string-to-string
definition. The result is a stompbox that
will happily move from vintage high-gain
zones to more contemporary metal territory
with ease.
Mad and Molten
At the time of this review, I was working
on a modern metal project that provided
the perfect occasion to explore the mind of
this particular Mad Professor, and I kicked
off my exploration of the Stone
Grey with a sweet, modern-metal
combination of a Gibson Les Paul
Baritone and a ’70 Marshall Super
Bass. With the Super Bass set up
fairly clean, the Stone Grey kicked
out a big, heavy, and tight metal
sound with a super-satisfying bottom-
end chunk. The Tone knob
was very effective for dialing in just
the right amount of crunch without
getting brittle. And the Distort
control can be dimed without
losing crucial definition. Staccato,
rapid-fire metal riffs were ultra
defined and still retained the basic
character of the Marshall.
Moving over to a Stratocaster,
I switched up the knob-setting
recipe by cranking the Volume and
backing the Distortion way down.
This setup is the ticket to a muscular
Stratocaster sound that flirts
with Hendrix’s and SRV’s heavier
sounds and crosses over into overdrive
territory. It’s hard not to be
impressed by this aspect of the
pedal’s flexibility. Most distortion
pedals that excel in high-gain territory
fall apart when working like
an overdrive. But the Stone Grey
is rangey enough to cover both.
I’m a sucker for stoner rock and old-school
Montrose, and the Stone Grey is
just as willing to go there too. With a ’74
Les Paul Custom, I jammed on “Rock the
Nation” and “Rock Candy” before changing
up the settings and hitting Mastodon’s
“Crack the Skye.” It’s almost impossible to
play the latter convincingly without ample
string clarity and punishing distortion, but
the Mad Professor kept up on both fronts
without a hitch.
Most 3-knob distortion pedals leave me
wishing I had access to more EQ options,
particularly bass and mids. The Tone
control on the Stone Grey, though, is surprisingly
effective and complete. As long
as you’re using a solid foundation for the
amp, there is no need for additional knobs.
While edgy, the Tone control doesn’t get
crispy, and backing off won’t make things
dull and dark.
The Verdict
The Stone Grey is a distortion pedal that
doesn’t step on the amp’s tone, it just gives
it a shot of adrenalin that can range from
massive to more mellow. The tight bottom
end enables you to play at killing
speed without loss of definition. The sheer
amount of distortion you can generate
without creating harmonic mud is astounding,
and the effective tone control can add
even more bite. Clearly the Professor is
Mad, but if this pedal is any evidence, I
think he might just be a little bit pissed too.
Buy if...
you want modern muscle-to-metal tones
in a compact and solid pedal.
Skip if...
you don’t have the need for all that
distortion.
Rating...
