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Groove Tubes Glory Compressor – A Real-World Review

In collaboration with the Conservatory of Recording Arts and Sciences, one of the country's leading pro audio teaching facilities, PAR has introduced a regular series of in-depth reviews conducted at the Conservatory's state-of-the-art teaching facility in Phoenix.

The father of a high school friend was one of the production team members for the Dodge Viper. One day he took my friend and me each out for a ride in one of the prototypes. It gave me a sense the Viper was more than a car; it was part art and part advanced technology. I had not had that feeling in years until I opened up the Groove Tubes Glory Compressor ($3,499). The Glory Compressor is a single-channel, three rack-space tube compressor with a feature palette that could keep even the most compressor-savvy engineer discovering new tonal possibilities for as long as they use the processor.

The Glory Compressor packs an impressive seven tubes into its all-tube-from-input-to-output design. It weighs in at 37 pounds and, due to the heat generated by the tubes, requests being housed in five rack spaces, one both above and below the unit for ventilation. It offers both 1/4-inch TRS and XLR jacks for both program input and output. It connects to power through a standard IEC connector. The Glory Compressor offers the standard parameter controls on most compressors, as well as numerous other features.

One of the first things that struck me upon opening the review unit was the number of knobs on the “older military-issue”-style front panel: fully balanced multideck ceramic switches for most of the functions, plus potentiometers for input, output and “Glory” control. The Glory Compressor offers ratio, threshold, attack, release, input and output controls, as well as side-chained EQ options from either an internal or external source, a thorough nine-position meter selection knob and the feature behind the name, the “Glory” control. The Glory knob, variably selectable between “Earth” and “Heaven,” introduces low-order even harmonics into the post-compressed signal. The harmonic bandwidth operates on fundamental frequencies between 40 – 700 Hz.

In Use

I had the opportunity to test the Glory Compressor over three different sessions on bass, drums, acoustic guitar and vocals. It was a welcome guest in every instance. I first used the Glory Compressor on a ’80s-style rock bass part. The bass ran direct into an OSA MP1A mic preamp, then into the Glory Compressor. Because of the nature of the song I wanted to get a medium amount of compression, achieving 5dB of maximum gain reduction. The part was mostly the root note of the guitar chords, so adding in the Glory control set about halfway to the “Heaven” side seemed to thicken the bass and allow it to occupy the bottom of the mix without sounding muddy. The compressor did not sonically tap you on the shoulder to announce its presence, even with 5 dB of gain reduction.

The Glory Compressor on drums was placed on an omni-directional modified C12-type tube condenser being used as a room mic. The Glory Compressor — placed about six feet in front of the kick and raised to be level with the toms — handled the transient attacks of the cymbals with ease, and the sound coming from the unit’s output was “the mix,” according to the artist. The Glory control again thickened up the kick drum and floor tom, while, due to harmonic bandwidth, leaving the snare and the cymbals mostly alone.

The Glory control took the spotlight on the bass and drums, but other features stood out on acoustic guitar and vocals. The ratio options as well as the side chain EQ came in handy while tracking a Tacoma Jumbo Koa that had been freshly restrung. The Glory Compressor, unlike most compressors that offer whole increment ratios, offers 1/4 dB changes between the 1:1 and 2:1 settings and a half dB step between 2:1 and 3:1. This meant a wildly dynamic performance could be captured with very subtle changes to the signal peaks; a very impressive level of control, to say the least. The side-chain EQ are fixed shelves at 50 Hz and 10 kHz with low-Q contours and +/- 10 dB in adjustment. This means the side chain EQ instead of acting as a de-esser was included to work on signals “overly rich in low or high band edge content.” The compressor became more sensitive to high frequency content by setting the 10 kHz adjustment counterclockwise into the negative setting. Finger squeaks were still present for the acoustic guitar, but less bright and forward in the performance.

I recorded vocals with a BLUE Bottle through a Neve VR preamp and the Glory Compressor across the insert. Using a ratio of 1.5:1 with a low threshold resulted in a very controlled signal, with the compressor consistently engaged while obtaining a low overall amount of gain reduction. Groove Tubes pulled out all the stops to provide a compressor that allows for tremendous flexibility in controlling signal. The singer, in a similar manner to my drummer, stated the Glory Compressor gave his vocals a very “finished” quality.

Another item that deserves recognition is the user manual for the Glory Compressor. The version I received was still a “preliminary” version, but I found it to be very useful; it combined enough technical info for the experienced engineer with very basic descriptions of functions and features in a step-by-step guide for newer users. Something I found interesting and unique in a processor of this style and caliber was that although the all-tube design screams analog the manual referenced samples in digital recorders when addressing how to use the attack control.


I give the Glory Compressor two very big thumbs up for quality of build, design, features, and performance. It deserves mention alongside the top compressors in pro audio, both today and from the time when tube designs reigned. It would certainly be more than a welcomed addition to my setup; it would become a featured processor on many different tracks.


“In all situations, the Glory Compressor imparted a smooth, strong character. I could not shake the feeling I was hearing a classic compressor.” — Phil Nichols, Assistant Director of Projects Conservatory of Recording Arts and Sciences

“The Glory Compressor made the drums sound huge in the room without sounding overly compressed. Normally, I am not a fan of room mics, but with the Glory Compressor I would use a room mic every time.” — CJ Vallely, Session Drummer

“The Glory control gives the sound a subtle, but unmistakable thickness that made the bass a solid foundation for the song. To say the Glory Compressor is simply a compressor sells it way short — its awesome.” — James Smith, Bassist and Assistant Engineer