Thermionic Culture Earlybird 1.2 Review
Reviewed by Huw Price for Music Tech

Thermionic Culture is a fairly new company, but with a great British boffin like Vic Keary at the helm, the vibe is resolutely old-school – Keary continues the British sound engineering tradition of building your own kit.

In the early days of commercial recording, there wasn't a great deal of choice when it came to gear. What was available was cripplingly costly, so engineers often made their own preamps, compressors and EQs. Keary built his first studio in the 1950s and has owned a few over the years, including Maximum Sound, Chalk Farm and Chiswick Reach. He founded Thermionic Culture in 1999.

Component culture

Thermionic Culture's circuit designs draw on proven and established technology from the 1940s right through to the 60s, but they've been refi ned and updated to achieve lower noise and distortion. Other circuits are Thermionic Culture originals. Modern components such as precision metal oxide resistors and polypropylene capacitors are used only where they can improve sound or reliability, and hi-fi gimmicks such as gold-plated XLR connectors are eschewed. Valves are mostly military or industrial grade, selected and matched as necessary.

This updated version of Earlybird employs upgraded output transformers that give it a cleaner low end and extra headroom, with negligible phase shift and distortion. Keary has retained the incredibly useful input impedance selector, offering 300Ω and 1,200Ω options, plus there's a three-stage high-pass filter with flat, 48Hz and 96Hz options. Gain levels are switched in 5dB increments from 40dB to 60dB and there's a -20dB input pad for coping with high levels.

The 5dB steps might strike some as a bit crude, but the Earlybird 1.2 has an output trim attenuator placed after the amplifi cation section. This allows for a little fi ne tuning as well as enabling users to accurately balance the two channels for critical stereo recording. Naturally, each channel has its own Phase Invert switch and the 48V phantom power switches are especially impressive because they are latching. This means that the shafts have to be pulled out before the switch can be moved, providing peace of mind when using vintage ribbon mics.

A matter of impedance

Only the impedance selector really needs explaining because – rather surprisingly – few preamps provide this feature. The manual suggests that "for most microphones 300 Ohms will give best results". However, 1,200 Ohms is recommended for FET and moving-coil microphones and well as older ribbon microphones such as Coles 4038s, which have an output impedance of 30–50Ω.

The sonic differences between the impedance settings when using a Beyerdynamic 201 moving-coil mic were subtle but clearly discernible – the 1,200Ω setting produced a brighter sound with a tighter low end. It was the same story with a valve Neumann CMV563. For vocal recordings we preferred the thicker midrange of the 300Ω setting, but 1,200Ω could win out for critical instrument recording.

An M-Audio Pulsar II with transformerless FET electronics sounded slightly smoother at 1,200Ω, so this is one occasion when you can trust the manual as well as your ears. However, all of our 1,200Ω recordings were slightly lower in level.

Competitive edge

We had a couple of valve preamps to hand to compare the Earlybird to – a Telefunken V72 and a hand-built copy of an Altec 1566 with Sowter transformers. All three shared some qualities, but the Earlybird 1.2 was the best all-round performer. Its gain levels made it better suited to ribbon mics, and the bottom end was consistently tighter and more focused. The V72 had a softer tone that might fl atter some sources and the 1566 was similar in the high and mid ranges, but the Earlybird's solid bass, lack of midrange colouration and sheer sense of space won out every time.

If your idea of a valve preamp is a grungy old thing that makes everything sound warm and fuzzy, then look elsewhere. The Earlybird 1.2 is the kind of preamp that tells it like it is. The tonal neutrality keeps the microphone centre stage, but it's never clinical or sterile.