Optical tube compressors are famous for their smooth leveling and transparent sound, but they’re not usually the go-to choice for characterful saturation. However, Heritage Audio’s new Tubesessor ($2,499.00) takes this classic design and kicks it up a notch, offering classic warm and musical compression with the option to spice things up with tube saturation and creative sidechain filters. If you need a great stereo compressor that can go from mild to wild at the turn of a knob, the Tubesessor deserves a place in your rack.
First and foremost, the Tubesessor is an optical compressor, meaning it converts the electrical input signal into light to activate a photocell which controls the compression circuit. Because of the way that photocells respond to light, optical compressors typically have a more gradual response curve than other types. That’s why they’re so great for vocals—they preserve the natural dynamics of the signal while smoothing out the overall level in a more “musical” way than simply setting a slow attack time on a traditional compressor. But that doesn’t mean the Tubesessor is all transparency, all the time—its tube circuitry and custom input and output transformers lend that special warmth you expect when you reach for an analog compressor.
Speaking of tubes, the Tubesessor’s secret weapon is its Tube Saturation knob, which sends your signal through a creamy-sounding, new old stock (NOS) Raytheon CK5755 double triode tube. The four-position switch with Classic, Mild, Medium and Hot options lets you dial in anything from a touch of bite to all-out, aggressive distortion. On the output, an audiophile-grade Psvane dual triode tube guarantees generous headroom. And before you worry about that NOS tube burning out, Heritage Audio has sourced a lifetime’s worth of them for repairs.
In addition to the typical controls for threshold, ratio, attack, release and gain, you’ll find a sidechain filter switch with five different options including two high-pass filters that stop bass-heavy sounds from overpowering the compression circuit, two mid-band filters that allow you to focus the compression on different frequency ranges and another high-pass filter at 5 kHz for making your compressor react to high-frequency information like cymbals. The attack and release parameters can be set to manual (knob control), fixed mode or a combination of the two. Finally, a quarter-inch Link jack on the rear of the unit makes it possible to link two Tubesessors together and process stereo signals with one set of controls.
We could go on and on about the merits of optical compression and tube saturation, but here are the highlights of this unique take on a classic design: