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Thermionic Culture The Swift EQ

Thermionic Culture The Swift EQ

4.25 4.25 out of 5, based on 1 Review

Tube EQ. Top notch, the best I've used.

28th September 2019

Thermionic Culture The Swift EQ by fromthepuggle

  • Sound Quality 5 out of 5
  • Ease of use 4 out of 5
  • Features 4 out of 5
  • Bang for buck 4 out of 5
  • Overall: 4.25
Thermionic Culture The Swift EQ

I've owned two other highly esteemed tube mixbus eqs before this, and several other high end mix eqs (ie: Sontec MEP-250ex), as well as quite a few more tracking and specialty EQs, as well as a lot of high-end tube preamps.

The Swift is without doubt one of the finest EQs I've ever used. It could easily be the only eq a person ever needs.


In the past there has been some concern with build quality on Thermionic Gear. I recently picked up a Culture Vulture standard unit, which I had stayed away from for so long because of mixed reviews. I was so pleasantly surprised to find that it was just great on all fronts, including build quality. The Swift is no different. These are completely top-notch pieces of gear, with top notch build quality. I should also say that I wrote Thermionic with a few questions about choices they made during designing it, and why some things are the way they are.

I got an email back from Vic himself, explaining in real detail why he made the choices he did. I was impressed by the personal touch. Vic expressed pride in the fact that 'if a little Air is added' there is "ZERO phase shift" and "extremely good signal/noise." Wow. Vic also said he went for active circuitry on highs to avoid the 'dull' sound of some passive units on the top end, as well as noise and phase shift involved in high gain amps in passive units. He also said the active bands are all active to avoid the 'unpleasant' ringing that can arise with inductors. Some of course like inductors for precisely their ability to ring and distort of course, and some may feel that 'dull' top end sounds more 'classic' (though to my ears Swift can do that too, just pull back the Treble control slightly), but that's all a matter of taste.


This is a super, super clean EQ. But that doesn't mean boring, on the contrary, like much high end tube gear, it is clear and euphonic in this way that only tube gear can be.

There are of course times when I want that thick distorted Neve eq sound, but a lot of times, I want an eq that can 'get inside the sound' and shift its balance of forces from within. When I turn knobs on the Swift, I feel like I'm inside the tone, and I only get that with top end tube eqs, and more with the Swift than others I've used on nearly all freqs.

I did try to push the Swift to distort at one point by putting a preamp with a lot of gain before it and another after it to stop it from clipping my interface. It did saturate, with peaks becoming harder and thicker, and the whole thing getting a bit flatter, with some hair. But unlike tube gear designed to saturate, this simply isn't what this unit seems to want to do. Honestly, I get my tube hair elsewhere, and I'd rather each bit of kit do what it does best at its best, than try to be something its not.

And what the Swift does, it does gloriously well. I sold my Sontec MEP-250ex to get the Swift, and I have no regrets. Different beasts in many senses, but there is so much hidden flexibility in the Swift, it rivals the Sontec! They sound very little alike, though. I will say that the Sontec has that kick drum snap to it, but the Swift has that wonderful Pultec-like thump, and while I will miss the Air on the Sontec (my Clariphonic is really quite close), the Air on the Swift is, like the kick-thump, simply the tube version of luscious Air, wonderfully sweet as well if in a different flavor.


What a peculiar beast, if a very powerful and sublime one! Now that I've got my head wrapped around it (only took a few hours of use to get comfy), it makes a ton of sense.

First, let me say that while the front panel doesn't have all that many controls, the switches hide a huge amount of flexibility. Easy to use, but a puzzle box of possibilities. I tried to go through the unit systematically, and I kept finding new combinations of bands, and bandwidths, even with boost just on or full, I finally gave up trying to be systematic about it.

The low end is thick and super warm, with an extremely useful hpf at the end of the chain to interact with the bass for that kick thump, pultec style. The mid bands sound wonderful, and they nicely can be made to overlap, as well as be either gentle or make some tight adjustments with high q settings.

The highs are what took me a bit to get, but makes a lot of sense now. Presence is a gentle shelf that has a little peak, three different settings, lowest is upper mids, two are in lower highs. Treble and Air are also gentle shelves, though Treble is steeper, though it doesn't get overly intense until there's a lot of boost or cut. Being completely passive, Air is wonderful and smooth. I found sometimes it made sense to push Air and Presence, other times Treble, and sometimes even boosting Air and Presence and rocking Treble slightly back and forth between them, letting it function as a tone control. Tons of flexibility.

This may sound a bit confusing, but in practice its not. Somehow it makes a ton of sense to my fingers, it's just a little different than I'm used to. But my ears love it.

On mixbus, I found the Swift incredibly powerful, sweet but rarely 'too much', powerful and muscular, able to move from broad sweetening to nearly surgical sculpting. When tracking, it was able to control tone in broad ways, as well as make more extreme changes to function 'like its own instrument', as some eqs can do when taken to more extreme settings.


EQs are so different. Sometime there is band on one eq unit that you just adore, even if you aren't into much of the rest of the unit. This isn't one of those. The Swift is perhaps the only EQ a person would ever need, especially if one wants tube clarity. It's largely clear, but in that thick and powerfully clear high-end tube type way.

This unit can compete with the more surgical solid state eqs in terms of flexibility, and the more colorful tube units for tone, but there doesn't seem anything 'middle of the road' about it, it's first in class, and can often beat these each at their own game. I'm not gonna say its the end-all-and-be-all of EQs, that's not how this game works, there's so many EQs with that one band that just beats anything else for a particular task. But I don't know if I've ever dealt with a unit this balanced, this sonically high class, not to mention super flexible, and now that I've groked its ways, easy to use. But really, its about the sound, and that's where this unit is one of the best I've heard.

This unit seems near perfect at what it sets out to be.


In many senses I find the Swift quite similar to the Sontec in tube form, even if they sound very different. This is a parametric tube EQ, and in that sense, similar to the Manley Massive Passive (which I haven't used).

What its not, nor is it trying to be, is something like a Pultec, particularly an MEQ, though Thermionic in fact make something quite Pultec-like, namely, their Pullet. It's worth comparing for a moment.

Pullet is able to make much more dramatic boosts and cuts in the dual mid bands than the Swift. Swift's passive mid bands are 15, 10, or 5db cuts and 15, 9, and 6 db boosts depending on q of high, mid, and low respectively. Pullet on the other hand boosts 21db max, with unspecified high, mid, and low q. The pullet also has a ton more freqs, going from 800Hz to a rather high 8kHz, higher than the 7k switch treble boost on the Swift. Air band on Pullet is selectable for 10, 12, and 15kHz, while that Air band on Swift is unmarked, but SOS says it has a corner freq of 8, peaks at 30, so I'm guessing the markings on Pullet are corner freq. From what I can tell comparing the Swift with an online video of the Pullet, the Pullet can make much wider and deeper boosts and cuts.

Like the Sontec, the Swift's approach to mids is largely in the realm of minor alterations, it's not the focus of the unit, which is rather a balanced approach to the freq spectrum, emphasizing attention to solid lows and a three part approach to the highs. Listening to the Pullet, I was like, wow, that would complement the Swift wonderfully. It almost seems like it was designed with that possibility in mind. The Air bands complement those on the Swift, and the much broader boosts and cuts on the Pullet could be fine tuned by those on the Swift. Gets pricey to have both, though.

What the Swift differs from a bit more directly is the standard Pultec. The Swift can do the 'pultec trick' with kick drum nicely with its cominbation of versatile hpf and active bass band. It's complex three-part control of highs, mixing active and passive, are however quite different from the Pultec. Pultecs use bells, if gentle ones, on treble boost, Swift uses shelves. And while the Swift can sound quite gentle in its treble boosts and cuts (especially if one moves as I recommended from Presence, to Air, to Treble, or kept moves of Treble within the first two of ten notches on the controls in either direction), it seems designed to be able to provide a slightly more modern approach to the highs. It does, of course, seem quite possible to get that more vintage sound to the highs, especially by pulling Treble back slightly, and using presence and Air to do much of the work, as the passive Air cuts through the slight darkening of the Treble, often supported by Presence.

It's a complex but powerful setup, but quite different from a Pultec. I wasn't able to a/b compare to see if the Swift got the high end 'silk' of the Pultec down, but honestly, its more important that it sounds good doing its own thing, and it most certainly does. Overall I found that at higher boosts, the Treble is a little thicker than more passive approaches to this, somewhere between the 'pillowy' soft of the Pultec, and the thicker highs of something like an API or Neve. It's an approach to highs I've heard on several other high-end tube EQs that combine active and passive (most of them these days that aren't direct pultec clones), and difference from Pultec on this is a matter of taste.

The Swift is also obviously quite different from those thick non-transparent eqs, thick and hard like a Neve 1073eq, that can provide evident inductor distortion and tons of character and even dirt when that's wanted. But such eqs can complement the Swift nicely.

Gentle but powerful, warm yet clear, broad and lovely yet able to be precise, refined but able to punch, and gorgeous all round. The Swift is absolutely superb, straddling the zone between a highly detailed surgical parametric eq and a broad sweetening eq. Clearly one of the greats, and especially if one has at least one solid state 'character' eq for tracking to complement it, the Swift could easily be the only eq, especially for mixbus but for tracking (less for mastering cause no detented switches), that a person ever needs.

Last edited by fromthepuggle; 29th September 2019 at 09:08 PM..

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