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Trident Audio Ltd S40 Channel Strip

The Trident Audio S40 ($2,495) is a single-channel microphone and instrument preamplifier, compressor/limiter and equalizer in a two-space rack mount case.

This year marks console designer John Oram’s 40th year in the recording industry. It also marks the 30th anniversary of the classic Trident Series 80 console.
Product PointsApplication: Recording

Key Features: Single-channel, microphone and instrument preamp, compressor/limiter, equalizer, Class A

Price: $2,495

Contact: Trident Audio/Guitar Center at 800-391-8762, Web Site
Oram started out in the 1960s at JMI Vox, helping to design the venerable AC50 and the 1141 “SuperBeatle” amplifiers among others. But he is best known for his contributions and designs during the 14 years he spent at Trident Audio Developments.

Oram and his company, Trident Audio Ltd., have resurrected the Trident name and have been releasing faithful remakes of Trident designs. The S40 channel strip combines elements of several vintage Trident products with more recent preamp and dynamics designs.


The Trident Audio S40 ($2,495) is a single-channel microphone and instrument preamplifier, compressor/limiter and equalizer in a two-space rack mount case. The S40 sports the familiar red and green aluminum knobs found on original Trident consoles. Oram indicates all circuits run under Class A conditions and that the latest components were used where noise matters, slower TL070s where the classic Trident sound needed to be retained.

The input section features a transformerless mic preamp and a Hi-Z instrument input. Front panel controls are a 48V phantom power switch, phase reverse switch, stepped input knob and 1/4-inch instrument jack.

Plugging a cable into the front panel instrument input jack switches into circuit via relay a 10M-ohm gain stage. Oram says he knows a thing or two about instrument preamps, having designed similar sections for Washburn, Martin, Lowden, Charvel Jackson and others.

The mic pre is based on the extended frequency response Trident TSM series input module. This is the same preamp design found in the Oram Pro range as well as the new Trident Series 80 5.1 console. According to the mnanufacturer, the preamp measures an E.I.N. of -126.4 dBu (with 200 ohm input source); at max output of +28 dBu, dynamic range is a whopping 154 dB.

Next on the front panel is the dynamics section, imported from Oram’s SonicComp range and the Series 80 5.1 console. Controls in this section are attack, release, ratio and threshold knobs as well a pre/post-EQ switch (normal state is post-EQ) and circuit bypass switch. The compressor circuit VCA is configured in side chain mode as a feedback element, so the signal path remains pure when the signal is below threshold.

The equalizer section combines the classic Series 80 four-band shelving/peaking EQ section with the TSM Series low and high-cut filters. The four-band section features ±15 dB high and low shelves with switchable knee frequencies of 7 kHz/12 kHz and 50 Hz/150 Hz respectively. In the middle are two ±15 dB sweepable bands with ranges from 150 Hz to 2 kHz and 1.5 to 15 kHz. Mid-band Q is one half octave and the shelves are 4 dB per octave. All boost/cut knobs are center-detented and the entire EQ section can be bypassed.

The output section features a center-detented output gain with a swing range of ±15 dB. A “vintage” VU meter can monitor either gain reduction of output level. Gain reduction zero VU reading can be calibrated via a front panel recessed trim pot.


My early 24-track studio experience was heavily Trident-oriented. For many years, Series 70 and Series 80 consoles were all I knew. So it was with fondness and curiosity that I set to work on reviewing Oram’s Trident Audio S40 hybrid channel strip.

After several initial sessions with the S40, it was apparent that these were indeed Trident circuits under the hood. The EQ section immediately recalled the trademark Series 80 sound.

At the same time, with the EQ bypassed, the box can produce clean (and loud) signals with full and wide frequency response. This makes for a highly flexible and creative “all-in-one” production tool.

Oram has smartly set the input peak LED to come on at +9 dB at the output, leaving a further 19 dB of headroom to cover transients and additional gain from added EQ.

At higher input ranges, pleasing character (i.e. subtle distortion) can be induced, though its effect on following circuits needs to be monitored and adjusted accordingly. This was especially true of the dynamics section, where higher levels at the preamp input can lead to smearing, even when the threshold was adjusted accordingly. This can equal great tone and warmth with instruments such as guitar and bass; on vocals, the effect was less suitable.

As always, attention to gain structure is key. I point this out because, in a multiple stage box such as this, monitoring internal gain structure is not as obvious a task. The effect of input gain on processors down the line is critical in understanding the wide range of tones this box can yield. Not to put too fine a point on it, but this is why I found the S40 to be an excellent tool for creative engineers to explore, but neophyte engineers used to “set and leave” boxes, presets and plug-ins may not be as enthused.


Overall, this is one of the best channel strip boxes to cross my studio desk. The box can yield a host of tonal qualities and color or act as a clean “straight wire” preamp; the highly capable instrument amp is icing on the cake.

Oram and Co. paid great attention to providing the working engineer with controls and tools that make sense and are, for lack of a better word, “musical” and not clinical.