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Trident 80B-EQ & Deca-Dent 500

500-series Module & Chassis By Bob Thomas
Published July 2017

Trident 80B-EQ & Deca-Dent 500

Trident’s celebrated EQ is now available as a 500-series module, and what better to house it in than the company’s very own chassis?

Vintage Trident consoles might never quite attain the lofty reputation, cachet and sheer desirability of some of their competitors, but back in the day they were very highly regarded. The Series 80, released in 1980, enjoyed considerable success. The 1983 Series 80B, due to its configurability and competitive price, not only became one of Trident’s best-selling consoles at the time, but also, alongside mixers from the likes of Neve, Amek, Cadac and SSL, helped build the stellar reputation that mixing consoles with a British ancestry still enjoy today.

These days, Trident produce a range of products based on their earlier designs, several of which incorporate the EQ section of the 80B. One such is the Series 80B Dual Channel, reviewed in SOS in April 2013 (, offering two channels of 80B preamplifier and EQ. At the same time as the Series 80B Dual Channel was released, a forthcoming 500-series version of the 80B EQ was announced — and that has now found a new home in the recently released Deca-Dent 10-slot 500-series chassis.


When it comes down to it, a 500-series chassis stands or falls entirely on the multiplicity of its connections and on the quality of its components and construction — and judged by those standards, the Deca-Dent passes all tests with ease and distinction. All audio inputs and outputs cater for balanced connections, and sit on the rear panel. Input signals enter via 10 high-quality XLR/TRS jack combination connectors, the first eight of which are paralleled on a 25-way D-sub connector wired to the AES59 (Tascam) standard. In contrast, outputs are available on 10 XLR-only connectors, the first eight also wired to another AES59 D-sub. I presume the lack of TRS connectors on the outputs is to keep costs down — combi connectors, as on the inputs, would present the wrong sex XLR, so the only way to accommodate jacks would be with additional sockets.

Usefully, the Deca-Dent features switches that cascade the output of one module space to the input of the next without requiring the use of patch cables. This means you can, for example, build an input channel from a preamp, an EQ and perhaps a compressor, with no need for patch cables. In addition, there’s a stereo-link switch that links odd to even-numbered modules. This switch is commonly used for linking compressor/limiter side-chains to maintain correct imaging when processing stereo signals.

Structurally, the Deca-Dent impresses with its hefty rackmountable chassis and its sturdy backplane PCB that carries, in addition to all the connectors and switches that we’ve talked about already, what are probably the highest-quality EDAC connectors I’ve encountered to date in a 500-series rack; they’re certainly the tightest-fitting ones I’ve used. Top marks all round!

Power is delivered to the modules (a full 130mA from ±16V rails to the circuitry and 150mA +48V of phantom power with all slots filled) from a chunky external power supply via a five-pin XLR connector. The presence of these voltages is confirmed by three LEDs that sit on the panel that fills out the last space-and-a-bit of the rack frontage.

80B EQ

The 500-series 80B EQ is a recreation of the original console’s four-band swept-mid EQ, and it’s designed to replicate the original’s wide bands and smooth overall character. Several present-day console manufacturers have made much in their marketing of their versions of ‘British EQ’ and its ‘musical’ qualities. Trident EQ circuits, from the A-series consoles onwards, are one of the small number of designs that are often referenced as defining the characteristics of this ‘British’ sound.

As in the original, the 80B EQ features two shelving bands that are switchable between 8 and 12 kHz for the highs and between 60Hz and 120kHz for the lows. The mid-range is covered by two peaking filters — 1 to 15 kHz in the high-mids and 100Hz to 1.5kHz in the low-mids. All four bands offer 15dB of cut or boost. Finally, there’s a switchable 12dB/octave 50Hz high-pass filter to assist you in reducing rumble effectively.

The 80B, like the Deca-Dent, is a beautifully built piece of kit. A chunky, metal chassis supports a thick front panel featuring the trademark Trident anodised green, red and black knobs. All switches illuminate when active and a solitary Peak LED serves to alert you when the signal levels inside the 80B EQ approach clipping. The internal circuitry comprises largely surface-mount devices, and is beautifully laid out (the component count isn’t particularly high, so there’s plenty of room). Reinforcing the build quality, the PCB carrying the output connectors may well be the best-looking I’ve seen so far.

Trident Tested

Inserting the 80B EQ into the Deca-Dent is not for the faint of heart or weak of thumb — it took me a fair amount of pressure to persuade a backplane EDAC to open its heart, and once in place, an even fairer amount of pull to get the 80B out of its embrace. In contrast, my API mic preamp went into the Deca-Dent without trauma and the 80B EQ slipped easily into and out of my Radial Workhorse 500-series rack. Connecting the Deca-Dent up presented no problems; I already use 25-way D-sub looms with my Radial rack, so it was simply a matter of swapping connectors, attaching the power supply and it was ready to go — and go perfectly it did.

The first eight of 10 individual audio inputs and outputs on the Deca-Dent are duplicated on AES59 (Tascam) D-subs, and combi connectors accommodate either jack or XLR connectors on the inputs.The first eight of 10 individual audio inputs and outputs on the Deca-Dent are duplicated on AES59 (Tascam) D-subs, and combi connectors accommodate either jack or XLR connectors on the inputs.

I’ve already alluded to the lack of TRS jacks on the Deca-Dent’s outputs, but there’s one other trick I think Trident have missed. The Deca-Dent has 10 slots, the first eight of which have their inputs and outputs paralleled on D-subs and XLR, leaving the last two slots without additional connectivity. If it had been up to me, I’d have put XLR and TRS I/O for slots nine and 10 on the right-hand blanking panel on the front, just to add a little more flexibility. But that’s a nice-to-have, not a missing essential feature.

When it comes to the 80B EQ module, I have no qualms whatsoever. It sounded and felt as lovely as a unit claiming its heritage should. My memories of working on an 80-series Trident console in the 1980s have obviously faded somewhat over the years, so I can’t say with any confidence that the 80B EQ sounds exactly like the EQ section of that much-loved console, but, importantly, the recreation does seem to have all of the original’s attributes as I remember them. Even though the 80B EQ, like its ancestor, is not what you’d call a surgically precise instrument — you’ve got no access to the Q of its mid-range filters — its can range in operation from being the source of gentle, unobtrusive correction to delivering some quite drastic sonic sculpting, without seeming to overwhelm the character of the source. It can be a very useful facility to have at your fingertips.


The Deca-Dent 500-series rack is a very high-quality piece of hardware. Although I’d personally prefer to see both XLR and TRS outputs alongside its XLR/TRS combination inputs, so that it would interface easily with almost any gear/cables, if you’re going to be plumbing it permanently into a studio patchbay (which, I suspect, is where the vast majority of Deca-Dents may end up), that simply won’t be an issue. While you might find yourself occasionally missing front-panel inputs to slots nine and 10, you could always make up a custom loom or rack it up with a patchbay.

The 80B EQ is simply a joy. Although I can’t claim with certainty that it sounds exactly like the original, it has all the characteristics I remember liking about Trident’s Series 80 EQ back in the day — so it’ll do very nicely, thank you, and I can see a pair looming in my credit card’s rear-view mirror.

I’d happily recommend the Deca-Dent to anyone looking for a 500-series rackmount chassis for a studio installation, where its sheer quality is going to mean a lifetime of trouble-free use. The 80B EQ is an absolute no-brainer if you’re looking to add some flavour from one of the most popular consoles of the 1980s to your tracking and mixing endeavours.


There’s a plethora of excellent 500-series racks available, so your choice will come down to the size and connectivity that you require. The API 500VR, Purple Audio’s Sweet 10, IGS Audio’s Panzer, Radial’s Workhorse and Rupert Neve Designs’ R10 are among those capable of hosting 10 modules, like the Deca-Dent. There are plenty of console-style EQs too, such as those by Neve, SSL, API, and Mäag, though I don’t know of any direct 500-series equivalent to the 80B EQ.


  • Both boast a very high build quality; the Deca-Dent’s backplane EDAC connectors are superb.
  • The 80B EQ has all the sonic attributes of its original and is a complete joy to use.


  • None.


80B EQ £369; Deca-Dent £740. Prices include VAT.

Deca-Dent $799; 80B EQ $399.

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