EXPERT opinion: Bruno Putzeys (Purifi, Hypex, Kii, Mola Mola)

  • Eigentakt — German for self-pulsing and the name lent by co-developers Lars Risbo and Bruno Putzeys to the self-oscillating Class D amplifier technology slowly emerging from under their Purifi umbrella that also includes, among others, Peter Lyngdorf and is simultaneously tackling loudspeaker driver design.

    Each Eigentakt 1ET400A mono module makes a footprint no bigger than an XL iPhone but operates at 94% efficiency — a sharp reminder why designers like Risbo and Putzeys favour Class D. This is high-end audio amplification for the climate change era. The specifications sheet pokes a first finger in outmoded Class D prejudice’s eye: 425 Watts into 4 Ohms, ~131dB(A) dynamic range, THD below 0.00017%, a sub-65μΩ output impedance (for sky-high damping factor) but a rather modest 12.8dB of gain – the rest must come from the partnering input stage.

    According to Putzeys, the Eingentakt’s specs speak to its audible performance, apparently a considerable step up from the nCore modules that he developed for Hypex. One Hypex hangover is the business model. Purifi will eventually sell Eigentakt modules to the DIY crowd but already underway is their licensing to third party manufacturers who will implement Eigentakt modules in their own commercial products.

    In recent weeks, Purifi has dispatched demonstration samples to Srajan Ebaen at 6moons and Doug Schneider at Soundstage!, each fitted with an in-house developed input stage and power supply and wrapped in a basic chassis. Both DIY-ers and commercial implementers are expected to supply their own.

    A pair of Purifi Eingentakt 1ET400A in the NAD Masters M33.

    The UK’s Nord Acoustics was first out of the gate. Their range of web-direct Eigentakt-based mono, stereo and three-channel amplifiers starts at £625 and increases according to the number of channels, chassis type and connectors.

    Nord has been closely followed by NAD who last week announced (via press release) that their Purifi-based integrated amplifier had finally begun shipping. Unlike the Nord, the NAD Masters M33 (US$4999/€4999) comes fully loaded with Future-Fi accoutrements – a BluOS streaming module and Dirac room correction – to squarely land within this publication’s purview and at this commentator’s door by way of UPS.

    What better time to get Bruno Putzeys on the horn to talk about Purifi’s Eigentakt but also the mathematical/DSP smarts deployed in the Kii Three/BXT and the Mola Mola Tambaqui DAC.

    Listen via SoundCloud, Spotify, Apple Podcasts or this embedded player:

    Watch a 2018 video interview with Bruno Putzeys here.

    Written by John

    John currently lives in Berlin where he creates videos and podcasts for Darko.Audio. He has previously contributed to 6moons, TONEAudio, AudioStream and Stereophile.

    Darko.Audio is a member of EISA.

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