Based on a classic design and bursting with transformers, the Successor from Heritage Audio combines a vintage sound with serious flexibility.
I'm not quite sure why, but of all the vintage approaches to compression, the diode-bridge circuit seems to be the one which has been least exploited by the many manufacturers creating either hardware clones or analogue-modelling plug-ins. It's all the more surprising given that the most notable examples of this technology — the Neve 2254 mono and 33609 stereo compressors — have proved enduringly popular in a number of roles, not least the 33609 as a stereo bus compressor. However, that situation seems slowly to be changing (see the 'Alternatives' box), and Madrid-based Heritage Audio are one of the latest companies to breathe new life into this old technology: their Successor, which clearly draws on the Neve approach, is a 1U rackmountable stereo bus compressor, manufactured in the EU.
A cursory glance and the Successor's front panel instantly reveals its muse, the painted, battleship-grey fascia and winged knobs giving it a particular vintage appearance that wouldn't look out of place in a studio from the 1970s. Though there are two channels, this is a true stereo compressor — so there's a single set of controls, which stretches across the width of the unit in an unbroken line from the all-black meter on the left to the power switch on the right. After the meter, which displays the amount of compression on its 0-20 dB scale, comes the Dynamics In switch, and in addition to activating the compression circuitry this also switches on the meter illumination — a very neat alternative to the customary green or red LED.
The Threshold control ranges from -20 to +20 dBu and, like the Successor's other rotary control (Blend), is detented to ensure repeatability of settings. Ratio is a six-position stepped switch, selecting between compression ratios of 1.5, 2, 3, 4, and 6:1, or a limiting ratio of 20:1. The Attack control is similarly stepped, accessing attack times that are initially pretty speedy (50 s to 0.2 and 0.5 ms), and then increase in ever-larger steps to 2, 5 and 20 ms. Release is another six-step switch, its first four positions covering times of 25, 50, 100 and 400 ms, and its final two steps switching in the A1 and A2 automatic release timings, which are fast when peaks are being compressed and slower when more sustained program material is being dealt with.
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