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Arcam CD36 Mods

The stock version of the CD36 has a highly polished sound, clean, precise, spacious, with detail aplenty. What it lacks is depth, bass weight, the bass notes are clean, defined but ‘thin’ sounding. The midrange to high frequencies have an open and polished sound, but err on the leaner side of neutral and do display a degree of high frequency glare. The sound-stage has good width but fails to project in front-to-back depth, height; which has a flattened perspective. There is also a tendency for the same to become compressed with complex passages of music.

With such a good foundation in design already in set we were keen to hear how much more performance we could squeeze out of the CD36’s circuits. We have two levels of upgrades available for the CD36. The level-1 upgrade addresses weaknesses in the system bringing the quality of sound up to a much high level, level-2 expands on this and maximises performance to achieve the optimum results. Level-1 upgrades start with upgrades to the audio PCB, this is a modular board which is fix to a large Aluminium heatsink and houses the 4x Wolfson WM8740 DAC’s, clock circuits, voltage regulation, analogue output stage. Electroytic capacitors are upgraded for the DAC & analogue output stage bulk decoupling for improved noise rejection, superior audio properties. The analogue output stage uses active op-amps, the OPA2134 are enrolled for filter & buffer stages. The 2134 is a good op-amp, but the sound is somewhat veiled, shut in, lacking dynamics and vibrancy. We upgrade the 2134’s for the buffer section with the superior AD825 op-amps on Brown Dog adapters. With the AD825 Detail becomes optimal at both low and high levels, dynamics are powerful and controlled, the music gains a warmer, more natural sound. Next we work back to the master clock system. Given the attention Arcam have already placed on the clock system, and I quote; “Ultra-low jitter master oscillators, with individually buffered and terminated clock distribution lines to all parts of the circuitry” it may come as a surprise that it is this area we first look at. The Arcam clock circuit is a single transistor oscillator (Colpitts) which is superior to most OEM clocks we encounter. All considered the Arcam clocks still fall well below the measured and audio performance of the Superclock 4-S, which by comparison uses an advanced oscillator circuit with discretely regulated power supplies for the analogue & digital circuits. The first level-1 mod upgrades the ‘master clock’ with Superclock 4-S bringing a welcome increase in depth, scale and body to the sound; loosing that thinner and leaner quality in the stock player. There is also significant improvements in resolution, dynamics and creating a realistic 3D sound-stage; music gains height and width with improved front-to-back projection. Finally we add a resonance control panel to the lid (top cover) using the Sontech SFRT-AL. This material is a sandwich foil and specially designed for removing specific bands of noise which are harmful to audio performance.

The level-2 upgrades build on the performance of those installed with the level-1, adding additional upgrades to the audio boards logic & clock decoupling circuits to drive noise down. The main analogue power supply reservoir capacitors are upgraded to Panasonic FC type owing to their superior audio attributes over the OEM Rubycon YK type. Bybee Slipstream purifiers are installed for the audio signal outputs. The improvements here are outstanding; the most obvious improvements were in bass and dynamics, you can hear more inner detail in well-known recordings, the sound-stage is broader and deeper with very precise placement of voices and instruments, both laterally and in depth.

Summary

These latest Arcam upgrades are amongst the best gains we have heard from Arcam CD players. The level-1 modified CD36 dealt readily with musical demands placed on it where previously it had startled to buckle under the strains of complex passages. Tonally any whips of thinness were gone, notes gaining substance and refined clarity. The sound-stage the modified CD36 conjured up was far more expansive and spacious and stepping free of the constraints placed by the stock player. Playing the prodigy’s ‘Narayan’ the lower end was now blessed with a greater power and depth, shaking any dust off the cones that may have previously settled. But it was not just all about increased scale and power here, the upgraded CD36 was equally a class act at orchestral works with a richer, more natural texture to notes allowing you to hear the variations in instrument timbre with greater insight of the recorded material. The level-2 modded CD36 advances on the level-1 performance and is equivalent to adding a £2K external DAC to the CD36; such is the increase in resolution, dynamics, detailing, clarity & openness.

This modification has been discontinued.