Keith Marshall

Ever since my teenage years I have been fascinated by the reproduction of recorded music. Building my own equipment was a financial neccessity in the 1960’s, which prompted me to find out how things work and how to to improve them – a learning curve that has continued to the present day, more than a half century later.
I was born in the UK but have resided in the Netherlands for very many years. I may be known to some as the owner and designer of the Dutch loudspeaker brand Impulse. I retired from doing this 5 years ago and have spent the intervening years pursuing my interests in analogue audio. Having recognised the overriding importance of the phono pre-amplifier I set about developing a couple of interesting models that would eventually prompt me to start up my old Audio Wise company again in February 2018. In this process I have been greatly helped by Richard Murdey of RJM Audio (see below).
More of less by accident I also stumbled upon the concept of the little known and understood passive pre-amplifier – a device which, when executed properly with state of the art components,  can not only replace a conventional pre-amplifier but outperform it by a considerable margin! The resulting new Audio Wise Passive Pre-amplifier  is also now available  together with HiFi Collective’s very versatile Glasshouse design.
In all of my involvement with HiFi equipment over the years I have discovered time and again that simple things tend to sound better than complicated ones – hence the theme for this website –

“Less is MORE” Audio


Richard Murdey

Richard, born in the UK and educated in Canada, is currently a research scientist at the University of  Kyoto, Japan, where he is working on organic semiconductors. Since his early student days, he has developed an interest in DIY electronics: activities that lead to him establishing RJM Audio in 1999 – which specialises in offering “homebrew” recipes and kits to the DIY audio community. Probably the most well-known of Richard’s projects is the VSPS – the Very Simple Phono Stage – a design in keeping with the “Less is More” principle that I strongly believe in.
Today his various headphone and phono stages have evolved into the Sapphire headphone/line amp and Emerald MM/MC phono stage, available as bare boards or kits at RJM Audio. Richard’s speciality is making attractive, electrically optimized board layouts, though he also enjoys simulation, electronics theory, and circuit design.
I am greatly indebted to Richard for providing me with his innovative circuits and very high quality printed circuit boards used in my range of phono pre-amplifiers. He has been a major source of inspiration in getting my products to their current quality.
The VSPS circuit together with the superb S-Reg (shunt regulated power supply) form the heart of my SOLO phono stage, while the more advanced and elegant Emerald design for MM and MC cartridges – also featuring the S-Reg – is used in the TRIO and TRIO P.

Lourens Ouweltjes


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