Thermionic Culture Phoenix

Stereo valve compressor

Thermionic Culture Phoenix Stereo valve compressor

Review by George Shilling

Vic Keary has been involved in Pro-Audio since the 1950s, when studios often had to customise and build their own solutions. This environment has ultimately led Vic to the happy position he now occupies as Research and Design guru of Thermionic Culture. Over the years, he has set up a number of recording studios, most notably Chiswick Reach in the early 1990s, famous for its extensive valve equipment. Since then, he has had time to pursue his own design ideas for outboard equipment featuring valve circuitry. Vic's Thermionic Culture partner Jonathan Bailes helps with design and oversees manufacturing.

The appearance of the Phoenix is striking. It is a hefty 3U rackmounter, with startling square VU meters. The upper casing is fashioned from bare steel sheeting punctured with a mesh of large holes, through which the major components are clearly visible. These comprise six valves (of three different, relatively uncommon types), three huge transformers, four potentiometer shafts (for service adjustments) two massive capacitors, and the aforementioned meters, all mounted on a bare metal base section. It is a measure of the design philosophy that huge shafted potentiometers are used for trims rather than the tiny trimpots found more commonly. The smaller electronic components and wiring are enclosed within the base. These are accessed by removing the bottom metal panel, which reveals familiar electronic components, but, astonishingly, no PCBs. Components are either attached to the casing or mounted on one of three solder-tag strips. This method of construction is almost unheard of in these days of computer design. The rear of this section includes the IEC mains socket, fuses, and two pairs of XLR connectors for input and output. The rough casing construction could be from a school metalwork class, but has a rugged appeal.

Thermionic Culture Phoenix Stereo valve compressor

The black front panel includes separate plastic-knobbed damped pots for each channel for Gain (input level), Attack, Release, Threshold and Output Trim knobs and Bypass toggle switches. There is also a Link toggle for stereo operation, or as the manual usefully suggests, sidechain control of one channel by the input to the other. The controls are free from any markings of conventional calibration scales. All knobs are simply legended from 1 to 11 - yes, the Spinal Tap joke has truly been done to death. To the right is a large Power toggle switch, accompanied by a torch bulb with a green cover to indicate power on. There is no illumination of the odd-looking VU meters. These meters are of Indian origin, and were reportedly spotted in a nuclear reactor control room in a certain Eastern nation. Thermionic Culture reject a large number of these due to sticking needles, but after one initially paused a couple of times they were fine. Their representation of the compression characteristics is not entirely accurate, as their movement is somewhat lethargic. This is no great problem, and one soon became accustomed to their nature. It should be noted that the Output Trim pots are placed after the electronics. They can be safely used to lower the output level for -10dB operation.

Loosely based on the Altec 436, this latest development of the design features a wider-ranging Attack control than the original prototypes. There is no Ratio control, as the design features a 'Vari-Mu' soft-knee circuit which ranges from <2:1 initially to >20:1 at 20dB compression via a pleasant curve. This makes setting up a doddle, the lack of conventional calibration forcing one to work by ear. Juggling the Gain and Threshold knobs enables a wide range of compression amounts, and the Attack and Release controls are extremely wide-ranging, providing a variety of useful settings. It is remarkably difficult to make things sound bad with this unit. The Phoenix has a very musical character, and certainly brought one of my mixes to life, controlling the bottom end beautifully, making the vocals more rich and juicy sounding and generally making the track sound more dynamic. I took an instant liking to it, and forgave its lack of calibrated legending straightaway. On vocals the Phoenix was truly a joy to use, suiting all vocalists I tried it with during my brief review period. Use with drums and bass were equally enjoyable. Noise levels were extremely low, and frequency response extremely wide. If I have any criticism, it is possibly that the sound of this unit is slightly too smooth and sweet, lacking a little raw 'graininess' of character found in certain older valve compressors.

The Phoenix is priced as a professional product, distancing itself somewhat from cheaper valve units flooding the lower reaches of the market. Taking into account the many years of practical experience behind this product, it seems like very good value. Indeed, the Phoenix compares favourably with competitors that are much more expensive. Construction is undertaken by hand by a team of just three people, which makes each one inherently more special than any mass-produced identikit box. The Phoenix is from a comfortingly old-fashioned Home Counties cottage industry: note the proud use of the word 'England' on the front panel. Its old-fashioned valve warmth brings a magical glow to any signal.

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