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Thermionic Culture Nightingale 2

Channel Strip
Published January 2015
By Matt Houghton

With its parallel inputs, Thermionic Culture’s valve-based channel strip enables all sorts of creative recording options. And it sounds great, too!

Almost all of Thermionic Culture’s valve processors are a little different in their own way, but I can’t think of anyone else who would have come up with a concept like their Nightingale. In fact, on first inspection, it struck me as being a little odd, yet after spending a while with it a year or so ago, this quirky creation began to make rather wonderful sense. At that time, I suggested the tiniest of feature enhancements (an EQ bypass switch) to Thermionic Culture’s Vic Keary, and they decided to incorporate that in a new version, the Nightingale 2, which I have in front of me now.


The basic idea is that you have dual-mic/line/DI channels, each with a three-band valve EQ. Either channel can be fed to the third channel, which features a valve compressor. Furthermore, the first two channels may be summed, so that both are fed to the compressor channel. This means that you can use the Nightingale as a conventional tube recording channel (preamp/EQ/compressor) or specifically to track dual-mic or mic-plus-DI setups (preamp/EQ+preamp/EQ, all running into a compressor). The first two channels each have a polarity-invert function, so the Nightingale 2 would seem, on the face of it, to be useful for tracking things like top and bottom snare mics, or dual-mic guitar recordings, for instance, or perhaps a DI-plus-miked-bass cab. In each case, you craft the sound while tracking and record to a single channel, in the time-honoured way, avoiding the modern self-inflicted problem of too many options at mixdown.

If that’s not flexible enough for you already, the compressor channel has its own dedicated line-level input, and every channel its own line-level output — so you could track both mics to separate channels, or choose to use this as three separate line-level processors while mixing. Maybe three really is a magic number.

Ins & Outs

Each designed around a 12DW7 (ECC832) valve, the Nightingale 2’s two preamp channels can accept mic or line signals via the XLR inputs on the rear, or a DI signal via the dedicated TS socket on the front. For mic/line signals, a knob near the large GR meter is used to select the appropriate gain setting. The 20-detent gain knobs (indeed all the gain knobs, whether in the preamps, the EQs or the compressor) are marked 1 to 10. These span the range from full attenuation to +5dB for line sources, +21dB for the Hi mic setting, and +34dB for the Lo mic setting. Plugging an instrument jack into the DI socket auto-selects the DI as the input source. There’s switchable 48V phantom power for each of the preamp channels, via a four-position toggle switch (off, A, B, A+B), with an LED per channel to indicate the current setting.

Thermionic Culture Nightingale 2 The third channel accepts external line-level sources via a rear-panel XLR, but also features a source selector, enabling you to switch from that to the channel A input, channel B input, or channels A+B summed signal, before routing this to the compressor.

The power supply is switchable to accept 110V (USA) or 240V (UK) mains power courtesy of the ubiquitous three-pin IEC inlet.

Tone Controls

The EQs are intended for use as gentle tone-shaping controls. I’ve already described the EQs as three-band, because the active control comes courtesy of Top, Pres(ence) and Bass knobs, but technically they could be described as six-band, as switchable top-cut, low-shelf, and bass-cut filters are also included.

The Top control applies a high-frequency (9.5kHz) bell boost, with the bandwidth getting narrower the more that boost is applied. It’s a continuous control which runs all the way from 0 to +12 dB, which is quite a hefty boost — yet it manages not to sound overly harsh when applied. Pres governs a mid-boost (2.8kHz) bell EQ, with similar variable-Q characteristics as the Top band, with a maximum gain of +11dB. Bass is another boost EQ offering 0 to +11 dB of gain, but this one’s a little different. It’s a ‘varislope’ design, in which both the slope and frequency changes with the amount of boost, ranging from flat (off) through a small 90Hz peak at the 5 setting to a heftier peak at 40Hz when set to maximum.

The Bass Cut and high-pass filter controls are intended to be used in tandem with the Bass boost. The first offers two low-frequency shelving options, and the idea is that you can use it to cut in the low mid-range, while using the main Bass control to restore the level of the lower frequencies. Hence, the Bass Cut turnover frequencies being, slightly counter-intuitively, at 200 and 800 Hz: the gentle slopes mean that the first option is 7dB down at 80Hz, while the latter is 6dB down at 200Hz. The high-pass filter, of course, ensures that no unwanted nasties are allowed through when boosting the low end. It offers 30 and 80 Hz options (6dB down at these positions, but with the curve getting progressively steeper lower down the spectrum).

The Top Cut control offers three settings — bypass, and two high-shelf attenuation options, one being -6dB at 8kHz and the other -8dB at the same frequency. This can be used in conjunction with the Top boost knob, in a similar fashion to the bass controls, but on its own it’s also a useful tool for gently softening a source, just taking the edge off overly bright sounds.

By any modern standards, these EQ controls are very broad-brush tools, but then they’re not intended to be surgical instruments — rather, they’re for gently massaging the source to achieve a pleasing character, and used in that way, it’s amazing quite how forgiving they are. You can achieve some truly beautiful results which sound that little bit larger than life, as is the case with so much high-quality valve gear. (I’ve yet to hear any plug-in do this sort of sweetening job quite so well.)

Easy Squeezy

The compressor, the design of which is based around three separate valves, is as simple to operate as you’d expect of an old-fashioned tube design. A Threshold control switches the compressor on or off, and is used to choose one of three threshold settings. The ratio and attack time have no controls, but the release can be set to slow, medium or fast. Dialling in the desired amount of compression is then a matter of juggling the input (Comp Gain) and output (O/P Level) controls. The former dictates how frequently and by how far the signal exceeds the threshold, while the latter is an attenuator. For anyone used to using a modern compressor with variable threshold and make-up gain, having an attenuator last in line might seem strange, but it makes good sense when you consider the signal path: in order to get the signal to exceed the threshold, you add gain to the source, so while the compressor reduces the dynamic range, your signal still ends up being louder than when it went in. The output level knob allows you to attenuate the signal to pass it on at a sensible level to whatever you’ve placed next in your signal chain.

On Test

To kick off my tests, I ran a number of different line-level sources through the preamp/EQ channels, just to see what the general sound was like. Without even applying any EQ, rock drum loops were lent a lovely vintage-sounding sort of vibe — ever so slightly ‘gritty’, but in that pleasing ‘flair’ sort of way that I’ve only ever heard with good valve gear. I soon realised that I could use the two channels for stereo processing, adding yet another string to the Nightingale’s bow. The only downside was that using this in stereo for drums left me also wanting a stereo compressor!

Three devices in one: each preamp/EQ channel has dedicated audio input and output connectors, as does the compressor channel.Three devices in one: each preamp/EQ channel has dedicated audio input and output connectors, as does the compressor channel.Putting an electric bass sound (a line-level recording) through the EQ was particularly rewarding: the ‘top’ band just rolled off any lingering harshness and twang from the picking of the strings, while the Bass control, combined with a 30Hz high-pass filter gave a wonderfully full and warm sound, without ever feeling overblown or flabby. This only got better when running the output of that channel into the compressor, which was smooth yet disciplined in its control, and again offered a distinctly old-school sound. Lovely. The DI input, which I tested with a lawsuit-era Rickenbacker bass copy, yielded results that were just as pleasing as when using a line source.

Not having a bass amp to hand, I also tried miking up a guitar cab (Les Paul Studio into a Fender Twin, with an SM57 close mic), while at the same time capturing a DI signal (via a DAV DI/Reamp box). I found it reasonably easy to balance the two signals. Ideally, given the lack of attenuation options on the main EQ controls, I’d have had a lower option to be available for the high-cut filter. Still, the device added a nice dimension to the DI signal, making it a little less flat or dull-sounding, and I was able to track to both main channels and the compressor channel to three separate tracks on my DAW.

Yet for all this, where Thermionic’s gear has really shone for me in the past is on vocals and on acoustic guitar, and it was the same with the Nightingale 2. On both sources, the mic pre and EQ combined to make a beautiful recording channel, which just made tracking so easy. The Mid and Top EQ boosts were particularly useful, adding a nice sense of breath (to the vocals) and air (to both), while being able to tame the worst excesses of a finger-squeak here and string-scrape there on the guitar.

I hear a lot of people preaching hate about using compression when recording, claiming that it’s an unnecessary evil given the low noise-floor of 24-bit recording. Despite the technical case to support that view, I think it a bigger evil to leave too much of that sort of decision making until mixdown, and I almost always find that applying a little gentle compression is useful, as long as I leave a little room for manoeuvre when mixing. It makes the job of mixing so much easier, and I find that thinking about this sort of thing helps me to appraise the sound I’m capturing rather better. And it’s this job of gently compressing things that the Nightingale 2’s compressor is so good at. I say gentle, because that’s how it sounds, but it was quite disarming to watch the GR meter while tracking a vocal: what sounded like an innocent amount of compression turned out to be somewhere around 9dB! The beauty of the dedicated line input for the compressor is that it can always run the recorded track back out through it for another pass later on.


Outwardly, this may seem a quirky device, but when you break it down into its constituent parts it’s a very neat package indeed. It’s an appealing toolbox for general tracking duties, and an excellent one for vocals in particular. With the second channel, the mix input to the compressor, and the dedicated I/O for all three channels, it extends the functions of a recording channel in a useful way and, importantly, offers some serious firepower when it comes to mixing.

Of course, the worth of valve gear isn’t just about the functionality: there’s also the subtle-yet-beautiful, musically pleasing sonic effect of running audio signals through thermionic valves. While tube gear doesn’t inherently have to sound ‘warm’, most of Thermionic’s gear does — I have a strong hunch that they’re partly to blame for the perception that tubes equal warmth, simply because their implementations do such a good job of it!

All of this doesn’t come cheap, of course — but two preamps, two EQs and a compressor, all high-quality valve types, is actually a lot of gear for the money.


There’s not really anything quite like this on the market. There are channel strips, of course — Thermionic Culture’s own Phoenix HG15, for example, Manley Labs’ Core, and Tree Audio’s The Branch being fine examples. But none of these offers the dual input channels. There are plenty of stereo channels, but none of those offer the ability to sum two tracks to one compressor channel. There are also few devices which offer such a modular approach to the I/O — SPL’s Frontliner being a notable exception, the only real option there is to piece something together in the 500 series.

Published January 2015