Trident A-Range 500 Series EQ Module Review
- High pass switchable: 25 / 50 / 100 Hz
- Low pass switchable: 9 / 12 / 15 kHz
- Peak LED
Another staple unit that you are able to see in many various studios worldwide. The Trident A-Range 500 Series EQ is a discrete-transistor recreation of the legendary four-band equalizer from the original 1970s A-Range console.
It features custom-wound inductors in the mid bands, vertical faders offering ±15dB of boost/cut, and switchable high-pass and low-pass filter banks.
We’ve found its inductor-driven saturation and natural transient compression deliver a musical warmth that’s hard to replicate digitally. Below, we’ll break down its control architecture, tonal characteristics, and best studio applications.
What Is the Trident A-Range 500 Series EQ?
The Trident A-Range 500 Series EQ packs the iconic four-band equalizer from the original 1970s A-Range console into a single-width 500 series module.
Designed by Malcolm Toft and Barry Porter, only 13 original consoles were ever built, making this a faithful re-creation of the original circuit that’s otherwise nearly impossible to access.
The Trident A-Range 500 delivers the original four band Trident A-Range topology through discrete transistor circuitry and custom inductors wound specifically for the mid-frequency bands.
We’re looking at a design that prioritizes signal integrity without digital compromise.
Its single-slot footprint means you can populate a 500 series chassis efficiently, while modest power consumption of approximately 60mA per module keeps rail demands minimal across multi-slot configurations.
The Sound of the A-Range: Inductor Tone and High-End Sheen
Because the A-Range’s two mid bands rely on custom-wound inductors rather than op-amp-based gyrator circuits, they introduce subtle harmonic saturation and a natural compression of transients that softens aggressive boosts into something intrinsically musical.
The discrete circuitry further colors the signal with gentle phase shifts that widen the stereo image rather than smear it, delivering that signature high-end sheen without brittleness.
Where clinical digital EQs expose every decibel of boost as a literal, sometimes harsh alteration, the a-range 500 eq’s musical equalization curves round off peaks organically.
We can push aggressive boosts on vocals and acoustic guitars, adding 10dB of presence, and the custom inductors keep the result silky, never strident.
Meanwhile, the punchy low end stays tight and weighted, resisting the mud that plagues lesser analog designs.
Four-Band Control Architecture: Fader Gain and Switched Frequencies
Four vertical faders and four stepped rotary selectors define the A-Range 500’s control surface, giving each band a dedicated boost/cut slider offering +/-15dB of continuous gain alongside a frequency knob that clicks through preset center or corner points.
This four band Trident A-Range® equaliser arranges its high and low shelving sections at the extremes, HF clicking through 8k, 10k, 12k, and 15kHz while LF covers 50, 80, 100, and 150Hz.
Between them, two inductor-driven peaking equalisers handle the midrange: HM spans a frequency range of 1k-7kHz, LM covers 100Hz-1kHz, all via stepped rotary frequency selectors.
The boost and cut amounts read instantly from fader position, and this use of faders makes it very easy to achieve visual recall mid-session, a critical advantage in any 500 series module workflow.
High-Pass and Low-Pass Push-Button Filter Banks
Sitting below the four-band EQ section, the A-Range 500’s dedicated filter banks offer three push-button frequency selections per section, 25Hz, 50Hz, and 100Hz for the high-pass filter, and 9kHz, 12kHz, and 15kHz for the low-pass filter. These fixed-frequency points let you surgically remove problematic content at both spectral extremes.
What sets this design apart is the simultaneous button engagement feature. Pressing multiple high-pass or low-pass buttons at once creates compound filter slopes steeper than any single selection provides.
Need to aggressively clean subsonic mud? Stack the 50Hz and 100Hz high-pass buttons together. Want to tame brittle top-end extension? Combine the 9kHz and 12kHz low-pass selections for a sharper rolloff.
This approach delivers flexible, creative filtering without adding intricacy to the signal path.
- Boost/Cut range: +/-15dB (variable via per-band faders)
- Choice of 3 highpass and 3 lowpass filters
- Equivalent input noise: -85dBu (unweighted, no boost or cut)
- Maximum output before clipping: +28dBu (10k load)
Real-World Studio Applications: Vocals, Guitars, and Drums
When you put the A-Range 500 across a lead vocal channel, the HF shelf at 10kHz or 12kHz with a gentle 3-5dB boost delivers that signature Trident “air” without the brittle, sibilant artifacts you’d get from a standard parametric push.
The inductor-driven HM band at 3kHz or 5kHz opens up vocal presence, cutting through dense arrangements without phase smearing.
On drum overheads, this equaliser adds top-end shimmer via the 15kHz shelf while the LM band at 250Hz controls muddy buildup.
For snare, boost the HM at 2kHz for crack and body.
Acoustic guitars benefit from the A-Range 500 HF shelf for sparkle and LM cuts at 250Hz for clarity.
Bass guitars gain focused weight through the LF shelf at 80Hz.
Is the Trident A-Range 500 Series EQ Worth It? (Final Verdict)
Having put the A-Range 500 through its paces across vocals, guitars, and drums, the verdict’s straightforward: this module earns its place in any serious 500 series rack.
The Trident A-Range 500 EQ delivers legendary vintage British console equalization with a unique place in audio history that no plugin truly replicates.
This 500 series EQ is built for:
- Tracking engineers seeking silky high-frequency air without harshness
- Mix engineers wanting inductor-based midrange character on every session
- Studio owners investing in timeless, client-attracting analog gear
- Professionals who prefer a fader-driven workflow over conventional knob-based EQ
- Anyone chasing extreme boosts that remain musical and phase-coherent
The combination of discrete transistor circuitry, custom-wound inductors, and versatile filter stacking makes this a definitive purchasing decision for innovation-minded audio professionals.
Frequently Asked Questions
Q: Can Multiple High-Pass and Low-Pass Filter Buttons Be Engaged Simultaneously?
A: Yes, you can stack multiple filter buttons simultaneously, sculpting steeper, more complex rolloff slopes. We’re layering filter curves like building blocks, giving you unique combined responses beyond standard single-frequency selections for precise spectral shaping.
Q: What Is the Power Consumption on Standard 500-Series Rack Rails?
A: It draws approximately 60mA on standard +/-16V DC 500-series rails, so you’re looking at minimal power consumption. We’d recommend verifying your rack’s total current budget when populating multiple slots.
Q: How Many Original Trident A-Range Consoles Were Ever Manufactured?
A: Only 13 original A-Range consoles ever rolled off the line, a lightning-strike production run. We’ve distilled that rare, inductor-driven EQ topology into a single-width 500 series module, putting legendary circuitry within reach.
Q: Does the Module Include an Overload Indicator for Clipping Detection?
A: Yes, it includes a dedicated Overload LED that alerts you to internal clipping, letting you push the discrete transistor circuitry hard while maintaining real-time gain-staging awareness, essential when driving those inductor-based mid bands aggressively.
Q: Who Originally Designed the Trident A-Range Console’s EQ Circuitry?
A: Malcolm Toft and Barry Porter originally designed the A-Range console’s EQ circuitry in the early 1970s. We’re talking discrete, inductor-driven topology that’s defined legendary recordings, and now you’ve got it in a single-width 500 series module.
Conclusion
We can’t overstate how remarkable it is that the original A-Range console’s DNA, sourced from just 13 units ever built, now fits in a standard 500-series slot.
The discrete transistor topology, custom-wound inductors, and four-band architecture deliver that rare combination of surgical control and analog warmth we’re always chasing. If you’re serious about inductor-based EQ character, the Trident A-Range belongs in your rack.
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