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Review: Thermionic Culture Culture Vulture

The Vulture could be our industry’s premier two-channel distortion box, an eminently flexible and character-building bit of hardware no one plug-in can “out-culture.” 

English manufacturer Thermionic Culture specializes in the use of valves (in the US we call them tubes), and thermionic circuits for their line of audio processors. However, thermionic circuitry does not define a singular “sound” for Thermionic Culture, not even hardly; the Culture Vulture — their flagship “professional distortion box” — defies having one main character and, as such, is eminently flexible.

This 2U, two-channel unit is becoming known for its highly detailed, complex control of valve distortion (from 0.2 to 98 percent THD), but it also allows the use of very minimally distorted tube saturation (via EF86, 6AS6 and 5963 tubes). This controllable density and thickness means the Vulture is potent on whole mixes (possibly even in mastering) and also stereo groups as well as individual tracks.


The Culture Vulture is a dual mono unit (there is no link switch); users can set it for stereo operation by matching control settings on both channels. Those controls include Drive, which determines level hitting the Vulture; and Bias, which controls the bias current to the 6AS6 distorting tube (this is what is seen on the Vulture’s meters, ranging from 0 to 1 mA). This bias control is the crucially operative one, as its interaction with Drive determines the depth and texture of the distortion: anywhere from glassy to thickly chunky and muted. All of this is preceded by the normal or Overdrive switch, which adds 20 dB of gain into the Drive section and takes the Vulture from moderated flexible warmth into over the top signal crushing.

The Distortion Type control is where the Vulture’s big artistic decisions are made. Triode yields even-order harmonics for a generally smooth, rich and pleasant-sounding distortion that is chewy and pliable when extreme, yet musically transparent and classily exciting when barely touched upon. Conversely, Pentode 1 is odd-order harmonics, which are much harder, ruder and not as subtle, but flexible. Pentode 2 is even more extreme, as it jumps into nasty distortion readily with a raspy snarl and not an ounce of moderation.

The Vulture also offers a low pass filter to lop off excessive high end at either six or nine kHz. The much-needed Output level control reins in all that fun-to-create gain, or users can add even more gain and dirt via Output. Frequency response is 50 Hz — 15 kHz, +/- 1.75 dB, with noise rated at -75 dBV.

Unbalanced I/O is provided on back-panel quarter-inch jacks with a front panel quarter-inch instrument DI jack as well as low level quarter-inch output jacks provided for the Vulture’s use as a guitar distortion box; it was originally designed to emulate the behavior of tube guitar amps. The Vulture will put out a considerable +17 dBV and the output is semi-floating; as such, it can be interfaced professionally with very minimal hassle, despite being unbalanced.

In Use

Strapped across a whole mix — in the cleaner Triode mode with moderate use of Drive and Bias — the Vulture did things that made me smile. Some frequency content was added in the 125 – 220 Hz range that I’d have to EQ out (not to mention the noise floor), yet the heft, girth and size added to elements of the mix made my unprocessed mix seem weak and plastic-y in comparison. This not-quite-distorted, “plumped up” sound is simply a must-have for big ol’ rock mixes or vintage recreations.

After engaging the Overdrive switch to start the seesaw balancing of the Drive/Bias relationship, I heard numerous and diverse tones jump out. Drum subgroups, bass guitars, keyboard patches, vocals and (of course) loops are all ideal candidates for Triode Overdrive. Set Bias for crisper output and some semblance of clarity, but kick in that LPF at 9k and try such use in parallel with some clean signal snuck in for definition; you won’t be disappointed. 

Pentode settings aren’t mix-bus friendly, no sir, but individual tracks can suffer such abuse rather nicely. This is where operation exceeds description, so let’s just say you must rely on the bias meter for help, try tweaking as well as simultaneous Drive/Bias twists and constant supervision of unruly output levels to uncover dream-come-true settings on the Vulture. Yes, “dream” — some of these settings are ridiculously cool on vocals, percussion and samples; think of Vulture user Trent Reznor’s brutally fun signal mangling, applied on most any input you desire.

The front panel DI had enough gain (with Drive cranked up around three-fourths) for my old-school passive bass, which sounded rather good on Triode and Pentode 1 — but on Pentode 2 with all the high-end filtered off and Drive nearly dimed (and way over-biased), I got the equivalent sound of Godzilla stomping cities — pure destruction. Ridiculous, in the best of ways.

In Pentode 2, I found this over-the-top setting that yielded a sort of a pseudo ring-modulated pitch double. No, I didn’t damage the review piece; the designers advised finding this setting and were proud of it. Way to go, you Thermionic ‘Culturers,’ you!


If we consider the Culture Vulture’s solid construction, quality components, proper ventilation, flexible modes of operation and ample user control, then it becomes apparent that this is a professional processor designed to last, eminently capable of all that it claims, and much more than you can imagine. My only complaints are a bit of noise and lack of I/O metering, so my recommendations are largely limited by the model’s specifics.

If the one channel Vulture Solo is the ideal processor for instrument rigs (please read the Vulture Solo sidebar) and the Culture Vulture is the ideal model for channel insertion and subgroups, then the Culture Vulture Mastering Plus (balanced transformer I/O, lower noise, better frequency response, stepped gain, more gain control) is the ideal bird for mixes and mastering.

The Culture Vulture streets for around $2,200 (approx. $3k for the CV Mastering Plus), making it more expensive than any number of distortion plug-ins. However, I suspect it would be rather difficult to recreate this Vulture’s non-linearity, abundant soul and tweakable pathos “in the box.” 

Rob Tavaglione is the owner of Charlotte, North Carolina’s Catalyst Recording.

Price: $2,550 list

Contact: Thermionic Culture |

Sidebar: Thermionic Culture Solo Vulture

The Solo Vulture is best suited for high-end instrument apps, and not just because it’s a one-channel unit, either. 

First off, it has input gain in four steps (5, 15, 25 and 35 dB), so even a low-level instrument in the front panel DI doesn’t need a preamp. It has additional Pentode and Tetrode modes (called Squash 1 and Squash 2) with yet more variety of useful timbres. There’s a Presence circuit (either out, half or full) that will be exceedingly welcome to an instrumentalist’s ears; let me tell you, as a bassist and guitarist, it has that little high-mid clarity boost that does so much for our note intelligibility, just like on a tube guitar amp. For extreme distortion settings, it’s a well-known secret that a mid-boost bell can turn mud into caramel; the Solo Vulture offers a Mid-Lift bump at one of five settings (0.5, 0.63, 0.85, 1.1, 1.6 kHz), though exercise caution: switching settings creates big pops.

There are output level controls for both Clean and Dirty operation and you can silently switch between them (light-sensitive resistors are employed, so no SS circuitry changes the tone) using the front panel quarter-inch jack; indeed, it is useful in the studio when setting levels, and even more useful as part of a high-end instrument rig (especially considering the Hi and Lo level back-panel quarter-inch outputs).

So, what I am saying specifically is:

Guitar players, insert the Solo into your FX loop for either subtle Triode saturation/density/sustain on your solos (a la country) or all jacked up in Triode (or even Pentode) as your “dirty channel” (a la rock).

Bass players, use the Solo as your preamp (or in your FX loop) and go easy in Triode for your “ballad setting” (extra bottom end and extra sustain, no dirt) or set it circuit-bender crazy in Pentode (maybe even Squash 1), with too much Drive, too little Bias, either Presence or Mid-Lift and some mandatory LP filtering at 4 or 9 kHz for hairy monster bass (a la vintage psychedelic fuzz bass or today’s nu-metal).

For acoustic/traditional instrumentalists in extremely amplified musical landscapes, the Solo becomes literally named; exchanged for the “step up to the mic” philosophy that bluegrass players know so well, Solo Vulture users stealthily make their solos competitive on today’s close-miked, high SPL, large ensemble stages. Use Triode only, tune Drive/Bias to just the right “hotness” without feedback, try either half Presence or a Mid-Lift that suits your frequency range and the 15 kHz LPF (maybe even 9 kHz): you’ll have pick sensitivity, clarity and borderline aggressiveness, yet no nasty finger noise or trash up top.

For the studio, all the above features would be just dandy on your loops, basses, drums, etc. However, you’d be far better off in the studio using a stereo unit; in that case, spend about $400 more for a full grown Vulture, like you should. —Rob Tavaglione