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Gordon Instruments Microphone Preamplifier System

A few years ago, Gordon Instruments' Grant Carpenter noticed that, in regards to microphone preamplifier technology, there is a considerable difference between "state-of-the-art" and "state-of-the-industry." His move to change that resulted in the creation of the Gordon Microphone Preamplifier System (starts at $3,500), a concept in preamplifier design that could single-handedly transform (read: improve) the sound of modern recordings.

A few years ago, Gordon Instruments’ Grant Carpenter noticed that, in regards to microphone preamplifier technology, there is a considerable difference between “state-of-the-art” and “state-of-the-industry.” His move to change that resulted in the creation of the Gordon Microphone Preamplifier System (starts at $3,500), a concept in preamplifier design that could single-handedly transform (read: improve) the sound of modern recordings. The Gordon offers 70 dB of gain in 5 dB increments (+/-0.1 dB) with an amazing bandwidth of 0.7 Hz – 700 kHz (yes, that’s somewhat beyond the response of the human ear).
Product PointsApplications: Studio

Key Features: Two or four-channel models; separate gain control unit

Price: $3,500 (options available); freestanding outrigger available at no charge

Contact: Gordon Instruments at 615-665-1005, Web Site.

The Gordon preamplifier is a transformerless, FET-based device with a completely discrete signal path. In order to maintain audio purity (minimum distortion and maximum dynamic range) the preamp uses switched, variable gain amplifiers without the use of feedback or attenuators. This is significant since most preamps amplify the signal by more than 100 dB before attenuating the signal back to the level of desired output and thus creating undesired sonic artifacts and coloration.

The Gordon Microphone Preamplifier System consists of the Preamp and the Gain Control. The preamp is a two-channel 16-inch deep 1RU device weighing 11 lb. The Gain Control, also a 1RU device, is 3 inches deep and weighs 2.2 lb. Each gain control can control two channels of amplification and is upgradable to four. To ensure the highest quality sound is attained, the Gordon pre is designed to be placed as close to the microphone or instrument as possible. To eliminate multiple trips between the control room and the studio, the gain control unit is designed to be placed in the monitoring position with the engineer. This provides all of the technical advantages of having the shortest cable run between the microphone and the preamp without losing the ability to make adjustments from the control room. The Gain Control and Preamp are connected with a standard microphone cable. This control cable can be run through the studio’s patch bay without any interference problems or it can be a standalone cable that simply runs from one room to the next. The cable has a high tolerance to noise and can be several hundred yards long without any adverse effects.

The gain control consists of identical controls for two or four preamp channels. The Control Range adjusts the gain in 5dB increments. The peak indicator level lights when the output level reaches +24 dB (6 dB below clipping). The mute button allows the preamps signal to be muted. The invert phase switch inverts the phase of the preamps output by reversing the signal of pins 2 and 3. Older versions of the Gordon Mic Pre (including the one I tested) included the invert phase switch on the preamp rather than on the gain control. Having to reverse the phase on the actual preamp instead of on the gain control was my only complaint with the operation of the Gordon Microphone System. This improvement was announced by preamp designer Grant Carpenter at the Fall 2002 AES show.

All of the connectors and controls on the Preamp are on the front panel except for the power connector, the ground lift switch and the gain control connector. The power connector, a standard IEC-320 connector with fuse holder, provides power to the preamp (the manual recommends at least 20 minutes of warm up before use). The gain control connector is a male XLR connector which allows a standard microphone cable to be used as a control line to the gain control.

The Low Input Z switch changes the input impedance from 2M to 1k ohms. The 48V switch activates phantom power. When the phantom power supply is turned on or off audio is briefly muted eliminating the potentially speaker blowing pop associated with most preamps (shouldn’t someone have thought of this before?). When phantom power is activated, the high input impedance drops to 13.6 kohms. The Status lamp lights to indicate the normal operation of the preamplifier and gain control.

The Preamp’s input and output connectors and additional controls are located on the front panel. A pair of female XLR connectors and balanced TRS 1/4-inch jacks (wired in parallel) provide audio input. Audio output is provided via a pair of male XLR connectors. The Gordon Preamp automatically senses the combined impedance connected to the output (determined by cabling, connectors, the input impedance of the next device in the signal path, etc.) and sets the operating parameters for the lowest possible distortion.

Carpenter devoted significant time and energy to the exterior design, even to the selection of the buttons and knobs. Unlike the majority of today’s equipment designers whose design is simply based on what looks hip and cool, the Gordon Instrument design is based on functionality and durability. After spending time at equipment rental shops and speaking with technicians, he found that some of the trendy high dollar designs don’t necessarily hold up that well in the real world. Gordon offers a warranty to repair or replace any unit found to be defective due to factory materials or workmanship for a period of five years.

In Use

I have been fortunate enough to be able to use the Gordon preamplifier for the last several months and I have continued to be impressed over and over again. In regards to accuracy and sonic purity, the Gordon mic preamp is simply the finest preamplifier I have ever encountered. Given that the Gordon pre automatically calculates and optimizes itself to the output load impedance, not only does the Gordon sound amazing but the next device in the signal path is likely to sound better.

The Gordon does a fantastic job recording kick drum. Rather than adding color to the sound (which is not always bad), the Gordon allows you to hear the true sound of the microphone and drum. I found I needed far less EQ than I typically use when recording kick drum and in a couple of instances I used no EQ at all (this rarely happens). I also found that all of my kick drum microphones sounded good. I routinely switch between an AKG D 112, an Electro-Voice RE20 and a beyerdynamic M-88 for kick and usually only one sounds good with a particular kick and pre. With the Gordon all three sounded good, so it was a matter of determining which sounded the best for the particular song.

Recording snare drum was equally satisfying. I again found that I needed very little EQ. The pre did an outstanding job capturing the crack of the snare’s attack as well as the fullness of the drum. The resulting snare drum sound was big without being boomy and bright with out being brittle. I had great results with a pair of Sennheiser 421s to record the toms on a four-piece kit. I also had great results with using the pre along with the Royer Labs SF-12 for drum overheads.

The 1/4-inch inputs on the front panel work well. I had no problems recording both keyboards and bass direct. Bass guitar through the Gordon is stellar. The sound is punchy and tight with a huge bottom end. Studio legend Willie Weeks (Doobie Brothers, Wynonna, etc.) liked the sound so much he purchased one for his bass rig. I also had good results using my Demeter Tube DI along with the Gordon to record bass.

The Gordon really shines with acoustic instruments and vocals. I used the Gordon and a pair of Earthworks SR-77s to record hammered dulcimer with doctoral student and percussionist extraordinaire Michael Aukofer. Having recorded the instrument dozens of times over the last decade, he was amazed at the sound and quickly proclaimed it the best dulcimer sound he has ever attained.

I recorded vocals through the Gordon using the Sony C-800G, the Brauner VM1-KHE, and the EV RE20 and in every instance I had fantastic results. If I owned the Gordon, the only reason I can imagine using another preamplifier, ever, is if preamp coloration was necessary to attain the desired sound.


Although Gordon Instruments is still a relatively small company it has already begun to make its mark on the music industry. With dedicated users in all genres of music, the pre is quickly becoming a necessity to top-knobs everywhere. If you can afford it, there is no reason not to make the Gordon Microphone Preamplifier System part of your assortment of gear.

Review Setup

iZ Technologies RADAR 24 hard disk recorder with Nyquest 96 kHz card; Alesis MasterLink hard disk/CD mastering recorder; Mogami cabling; Hafler amplification; PMC TB1, AML 1 monitors; TubeTech CL-1B, Empirical Labs Distressor compressors, Pendulum Audio 6386 Variable MU compressor/limiter; Demeter Tube DI box; Brauner VM1-KHE, Sony C-800G, Royer Labs R-121, R-122, SF-1, SF-12, AKG C 28B, Earthworks SR77, AKG D 112, Electro-Voice RE20, beyerdynamic M88, Shure SM-57, Sennheiser 421 microphones.