Thermionic Culture Solo Vulture
Thermionic Culture
Solo Vulture
Valve Distortion Processor
When it comes to valve distortion, few want
it more than guitarists— and few know more
about it than Thermionic Culture...
t seems only yesterday that UK-based
company Thermionic Culture came
to my attention with their ‘Culture
Vulture’ valve processor, but they’ve been
around since 1998. Almost a decade
and a half later, the company have
developed an enviable line of valve-based
processors, the names of which have all
been inspired by our feathered friends:
how time flies!
At the time of writing, Thermionic
Culture were on the cusp of celebrating
their 1000th sale of the original Vulture
— although, with various special editions,
the total number of sales is closer to
1750. That’s an impressive feat for
a processor of this price, and something
that’s testament to the affection so many
engineers feel for the design. The Vulture
is all about distortion, and while some
things have changed over the years —
notably, desigers Vic Keary and Jon Bailes
claim a 15dB decrease in the noise floor
since the original SOS review by Hugh
Robjohns — it’s the same basic design:
a two-channel, valve distortion processor,
based around a 6AS6/5725 distortion
stage, with line inputs on the rear, which
cut out when plugging into the direct
inputs on the front panel.
What was unique about the Vulture
when launched was the degree of
control it gave you over the nature of
the distortion, with selectable distortion
types, and a ‘Bias’ control enabling
you to vary the current flowing through
the distortion valve. There are also two
outputs per channel: a line-level one, and
a ‘low’ one, intended to feed into guitar
amps. All of which brings me on to the
subject of this review, the Solo Vulture.
Flying Solo
As the name implies, the Solo Vulture is,
in essence, a mono version of the Culture
Vulture — and it is, indeed, based around
December 2012 / w w w . s o u n d o n s o u n d . c o m
similar valve stages — but that description
paints a less than complete picture. The
preamp stage uses a 12AX7, compared
with the original’s EF86, to provide two
stages of gain, the reasons for which will
become apparent. The output valve is
a 5965 type, compared with the original’s
5963. The reason for this is to provide
greater gain and a higher output.
While the Solo Vulture offers all the
features you’d expect from the Vulture, it
has also taken some of the shiny marvels
from the special edition (perhaps they
should have called this one the Magpie?),
and incorporates some features that will
be of particular interest to electric guitar
and bass players, who together should
form a significant part of the market for
a mono distortion channel such as this.
The shiny black front panel is
printed with a two-tone legend, the
white lettering dedicated to the ‘clean’
functions — the stepped input gain,
the DI input, a footswitch input, on-off
toggle switch, and half of the clean/dirty
switch, which is, again, a toggle type. The
orange printing describes the functions
dedicated to the art of distortion. These
include controls that will be familiar to
anyone who’s used a valve amp or pedal,
and some that won’t be, and many of
Lifting the lid of the case reveals neat
construction and circuitry.
them run from a spineless ‘1’ all the way
up to a presumably Spinal Tap-inspired
‘11’ setting. The non-detented ‘drive’
control does exactly what you’d expect,
as does the stepped Presence control,
which offers two settings for a broad
presence boost (the third being ‘off’).
Another switched rotary control governs
a low-pass filter that rolls the top end off
the dirty channel (with settings of ‘out’
and 15, 9 and 4 kHz available).
That’s all pretty standard stuff,
though, and the controls responsible
for the more interesting aspects of
this device are the Mid-Lift, Distortion
Type and Bias controls. The Mid-Lift,
which has been carried over from the
Vulture Anniversary Edition, is a narrow,
mid-frequency boost. Like the low-pass
filter, it’s switchable, this time with
centre-frequency options of 0.5, 0.63,
0.85, 1.1 and 1.6 kHz, as well as Off. By
changing the centre frequency of any
boost, you change how your amp reacts
to the signal. The brief, but helpful and
user-friendly, manual suggests setting
the Mid-Lift frequency to the key of the
song you’re playing, as well as suggesting
suitable settings elsewhere on the Solo
Vulture to use with this feature.
The Distortion Type switch presents
the user with four different options
compared to the original Vulture’s
three, with the legend describing the
settings as ‘T’, ‘P’, ‘SQ1’ and ‘SQ2’ As
on the Vulture, the ‘T’ position provides
a triode configuration, which generates
mainly even-order (ie. smooth-sounding)
harmonics, and the single ‘P’ option
(there were two on the original) puts the
device into a pentode configuration,
generating mainly odd-order harmonics,
for a more aggressive sound. SQ denotes
‘squash’ options, which are intended
for anyone wanting more filth and a bit
of compression/saturation.
The Bias control, with its adjacent mA
meter, was for me the most interesting
feature of the Solo Vulture, and the one
that makes this device really stand out
from the crowd of distortion processors.
Basically, it enables you to starve the
distortion valve of current or to over-feed
it, the practical outcome of which is
that the user has a very interesting
tone control: in keeping with the feeding
terminology, when you starve the valve
the sound gets thinner, and as you feed
it more, it becomes increasingly rounded.
When you get into over-feeding territory,
though, the sound really starts to break
up, as if the device is faulty — it’s not, but
my point is that there’s more control here
Thermionic Culture
Solo Vulture £1332
R5Reassuring build quality.
R5All-analogue signal path, including
R5Intuitive in operation, but with a helpful
manual, should you come unstuck.
R5Applications both in the studio and
a bassist’s/guitarist’s live rig.
R5Output levels vary significantly between
distortion types.
R5A few extra features could benefit a lot
of users.
One of the best distortion processors on the
market is now available as a mono device,
with extra bells and whistles to make it
well suited to guitar and bass processing —
but without compromising its suitability for
use on other sources. You could think of this
as the first half of an excellent guitar amp, or
as a great piece of studio outboard.
w w w . s o u n d o n s o u n d . c o m / December 2012
The rear panel sports two different level outputs,
and a switchable power supply capable of
operating at 110V or 240V.
than anyone should need, so all tastes
should be catered for.
The clean channel is a new feature,
too, providing an active stage between
the input and output (the original Vulture
had a hard bypass). This is, of course,
for the benefit of guitarists and bassists,
who can then balance the clean and dirty
output levels so that they both present
the same sort of level to the amp.
Test Flight
To get a feel for the Solo Vulture, I played
both guitar and bass directly through it via
the front-panel DI, feeding the ‘Lo’ output
into my Fender Blues Deville’s power-amp
stage, and later tried feeding it directly
into my DAW at line level, monitoring
the dry distorted sound without any
power amp or speaker colouring the
resulting sound. I then used it as an insert
processor for a few alternative sources
with my DAW.
The first thing to say is that the unit
oozes quality. It feels nice, solid and
well built, and the case is well enough
ventilated that it didn’t get unduly warm
during my tests. The front panel is neatly
The character of a distortion processor
comes down very much to personal taste,
which makes it really difficult to recommend
specific alternatives, and there are few that
offer so much control, or which have been
designed so specifically with both the studio
engineer and guitar/bassist in mind. Driving
any tube or transformer-laden preamp or
processor into distortion is one alternative,
perhaps combining that tactic with a little
pre-distortion compression, but the tonal
results will vary immensely in character. For
outboard gear that’s dedicated to the art of
distortion, the other Vulture processors are
worth consideration, as is the Looptrotter
Monster — and perhaps a few of the better
guitar-preamp pedals will get you into similar
territory, albeit without the same degree of
functionality and versatility.
painted in a glossy black, and it’s cleanly
laid out, with plenty of space between the
controls, all of which I found very intuitive
in use. The sound is everything I’ve come
to expect from Thermionic Culture’s
high-quality valve gear, with everything
from thin and brittle, through warm and
rounded to woolly fuzz on offer, and being
able to switch between the clean and dirty
channels with a footswitch, as if this were
a guitar amp, was great. Once I’d found
a setting I liked, it was easy to balance
the clean and dirty levels, though I should
note that there’s no level-matching
between the different distortion settings,
and that you’d therefore be left with
a certain amount of juggling to do to
match the clean and dirty channel output
levels if you were to switch between
distortion settings mid-performance —
between songs at a gig, for example.
I can understand why this is the case,
but it would be nice to see the output
levels better matched, somehow. While
I’m on the subject of output levels, it’s
worth noting that this thing seems to
kick out a hell of a loud signal at times,
whichever output is being used! Feeding
my RME Fireface 800’s line level inputs
(with no gain provided by the Fireface),
I was doing all the level tweaking in
the 1-2 region of the dirty channel for
some settings, to avoid overloading the
interface’s inputs, and I found this a little
fiddly — although, in the event, perfectly
doable. |It’s hard to be too critical about
this aspect of the Solo Vulture, though,
as the levels are inherently related to
the settings you choose: there are much
quieter settings available, particularly
when you bring the Bias control into play,
for which you’ll want to turn the output
levels up much further.
For both guitar and bass, this is
a beautiful, rich-sounding distortion
processor, but the applications stretch
far beyond that. I routed various sounds
through it to see what I could come up
with: amongst other things, it was great
December 2012 / w w w . s o u n d o n s o u n d . c o m
for overdriven rock vocal effects, for
smacking a bit of attitude into a humdrum
mono drum loop, for lending a bit more
grit to snare drums, and for fattening up
soft-synth patches, lending the sound
a real and desirable analogue flavour.
In short, then, I’m a fan, although
I probably wouldn’t quite class the Solo
Vulture as ‘perfect’ for me. As well as the
level-matching issues I discussed earlier,
I’d love to see the option to high-pass
filter the signal running through the
distorted channel, and the ability to blend
between the clean and dirty channels, as
this would make the Vulture much more
versatile on sources such as bass, drums
and vocals, allowing you to keep more of
the energy of the low frequencies intact.
‘Combi’ input sockets on the rear might
also have made integration into some
setups easier without pushing up the
cost significantly. But while such features
do appear on my wish-list, they aren’t
major criticisms, by any stretch of the
imagination. In fact, this is a stunningly
good distortion processor, and definitely
a worthwhile refinement of a piece of
gear that already deserves to be called
a classic. The price isn’t in stomp-box
territory, so it a will be a serious purchase
for the non-professional guitarist or
bassist — but given the quality of design
and execution, and if you think of this
as a combination of tube preamp, tube
distortion processor and EQ, it’s actually
very fairly priced. For the non-guitarists
out there, it’s got just as good a chance
of making it into the studio rack as it
has a guitar-amp rig, and the price will
probably seem keener in comparison
with similar-quality studio outboard.
£1333.20 including VAT.
Thermionic Culture +44 (0)1279 414770.
[email protected]
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This article was originally published
in Sound On Sound magazine,
December 2012 edition
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