I'll begin this review with a confession; in over two decades of mixing albums I've rarely mixed through a bus compressor. Why? The more I kept hearing that I "had to" in order to get good results, the more I balked at using one. I'd tried out the stereo compressors that I owned and was never quite enthused enough – plus I was getting decent mixes without a mix bus compressor, so why did I have to change my style of working? But when Phil Moore at Retro Instruments sent me his new Revolver two-channel tube compressor to try out, I realized it seemed to be built specifically for mix bus compression (but certainly not limited to this function), and that to get full value out of this unit I'd better try mixing through it. This may have changed the way I work forever.

In 1959, EMI Studios (Abbey Road) purchased several Altec 436B compressors, and they were majorly modified by staff technicians and eventually sent out into the studios as the RS124. Many of The Beatles' instrument tracks, submixes during bounces, and full mixes benefitted from these custom units. Revolver, likely named after a certain LP, is supposedly based on the RS124 but is a completely different device. The two channels of compression are simple to set, with Input and Output knobs reminding me of Universal Audio's 1176, or Retro's own 176 (based on UA's predecessor to the 1176 – I own two of these) [Tape Op #66]. Attack and Release knobs add proper control. There is a shared Dual Threshold, and, when using the channels in mono on different sources, I just left it at 12 o'clock and used the Input knob to push the signal in for more or less compression. A dual position 6 dB detector roll off Sidechain (90 and 250 Hz) is super handy, and a Link switch is, of course, present. One might complain that Revolver features no bypass of any sort, and no output metering (meters show gain reduction only), but I didn't really miss either of these. All mixing was done via my Rupert Neve Designs 5088 console [Tape Op #73], and the handy "ST Insert" button allowed me to continually A/B compressed and uncompressed mixes.

There's something unreal about this device; everything I ran into it came out sounding better. It's euphonic all the time, and that is something I rarely find these days. I don't understand how, but mixing through it, and using it as a limiter on unmastered/uncompressed mixes, I always felt the phantom center of the stereo image become tighter. For weeks I kept assuming I was wrong, but I kept hearing this effect. Mixing albums through it was a treat, and even though I printed simultaneous "uncompressed" mixes, every client was happy with the mixes done through the Revolver.

I wouldn't use Revolver on mixing sessions only; that'd be a waste. Acoustic guitar benefitted from the 250 Hz sidechain, where I could control rhythmic strumming yet keep a solid low end in a mix. Vocals always sounded great through Revolver, though I couldn't go as crazy on gain reduction as I do with lead vocals on my Retro 176. For one session I decided to use Revolver as a compressor on the drum submix bus. It was similar to the effects I'd found on the main mix, bringing an increased clarity to everything and making drums sit well in the mix.

When I received this unit I purposefully did not look up its price. Retro gear is built with tubes, lots of thick, grey metal, and sturdy parts. After using it for a few weeks I decided it must cost over $4000; I was shocked to find out it was about a grand less. The basic concept of compression and limiting – reducing the volume peaks and then bringing the average volume back up – is a walk in the park for Revolver, and it does so with style. It has worked its way into my mixing, my studio, and my heart.

Tape Op is a bi-monthly magazine devoted to the art of record making.

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