Locomotive Audio WT-Comp

This characterful valve processor offers vari‑mu compression at a very attractive price.

I’m a paid‑up member of the vari‑mu fan club. I own, and have owned, a number of this type of valve compressor, and it seems to me that their only downside is that the really good ones tend to be rather expensive!

I was intrigued, then, when I first learned of Locomotive Audio’s WT‑Comp (aka the Weight Tank): it seemed to tick many of the boxes I look for in terms of features, while being priced very competitively. Locomotive are based in St Louis, Missouri, from where designer Eric Strouth began to release his interpretations of classic recording gear in 2015. Hannes Bieger reviewed the Model 14B in SOS May 2017 and was full of praise. Whilst it’s by no means expensive (in vari‑mu terms!), the 14B is priced more in the ‘normal’ realms for high‑end valve gear. So I think it’s fair to say that the WT‑Comp is Locomotive’s attempt to make this style of tool more accessible.

Locomotive say the WT‑Comp takes its inspiration from various classic compressors, including the Universal Audio 175B and the Altec 436A (and its British mod), along with some aspects of their own 14B, and the goal here is clear: thick, characterful compression that can not only control the dynamic range but, to a degree, change the personality of the audio that passes through it. The literature reinforces that idea: it seems keen not only to describe the quality components that our audio will encounter in the signal path, including three (input, inter‑stage and output) all‑steel transformers and two valves (a 6BC8 and a 12AU7), but also to offer up the sort of colourful adjectives that might encourage people to stray outside their DAW when mixing.

With its sizeable vintage‑style input and output controls, large VU meter and chunky switches, this compressor feels reassuringly well built and pretty hefty too. Power comes in on an IEC inlet with integrated fuse holder; the voltage is switchable between European and US mains. With a fixed 4:1 threshold, the front‑panel controls are nice and straightforward: gain reduction is achieved by playing with the large input and output dials and there are controls for attack and release, along with the...