Check the listing for details. Trident Audio Developments A-Range 500 EQ. Condition: Very Good - Refurbished. Listed at 719.99 USD. The Legendary Trident A-Range EQ in a 500 Series Module The Trident Audio Developments A-Range 500 Series 4-band equalizer boasts a distinguished pedigree. Delivering an essential ingredient of the sound that launched hundreds of hit records in the 1970s and beyond, the A-Range 500 Series EQ is inspired by the all-discrete transistor circuit developed by Malcolm Toft and Barry Porter for the revered Trident A-Range consoles, only 13 of which were ever built. Accordingly, the Trident A-Range 500 equalizer infuses signals with rich analog warmth, verve, character, and punch, making it a welcome addition to modern DAW-based studio setups.Masterful 4-band EQ The Trident A-Range 500 EQ packs ample functionality into a 500 Series module.