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AudiophonicsTM is the name I use for my audio
designs which I originally developed between 1992 and 1996, and continue to work on some thirty years later.
I was prompted to design the 8"
Sphere Speakers as I was
unhappy with the sound quality of conventional square box speakers.
There were also visual issues of a domestic nature to consider.
The Sphere Speakers
were demonstrated at the 1993 Hi-Fi show at Heathrow, along with my
Marble and Granite Shelving System.
The Sphere Speakers
also featured in several Hi-Fi and other Lifestyle magazines including
GQ and House & Garden (see the
Reviews Page).
Following on from the
Sphere Speakers I
designed a separate Bass
Speaker to extend the low end response. I considered several options
and in the end settled on a sealed box design with two drivers mounted
face to face. I was particularly keen to be able to reproduce classical
organ music (Bach for example) which can play havoc with ported designs.
The Sphere Speakers
however were so accurate with their light and fast aluminium cones ("The
only enclosed speakers that sound as transparent as electrostatics."
from one knowledgeable listener) that deficiencies in the audio quality,
in particular the power amplifier, became apparent. So I went back
to first principles and after much contemplation the principle of the
Zeus Audio Amplifier was born.
Original Zeus Amplifier Schematic - 1994 (updated
2004).
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It took me the best part of two years to get from "I
wonder if..." to "It works - and I understand why!". Along the way I had
some interesting times trying to unravel the mysteries of transformer
design.
Once I had the amplifier part of the audio chain sorted
out my attention then came on the source reproduction side of things, as
now deficiencies in that quarter were now apparent!
So in 1996 I built my own CD player from a hacked SCSI
CD-ROM drive that had front panel controls for track selection as well
as the standard play/stop button.
2004 - I restarted my audio work and over the
subsequent months designed the upgrade Zeus75 power amplifier.
Investment in a Hi-End sound card and measurement software gave me new
tools for measurement and optimisation that I could only dream about a
decade previously.
2005 - I extended the Zeus philosophy to a pre-amp /
line driver and prototyped both mosfet and tube single ended versions
using the same input and output transformers in both cases.
2006 - I started development of a RIAA pre-amp
front end and a tone arm.
2007 - A the beginning of the year I built my end to end
Zeus system which is used for daily listening (as opposed to "bits on
the bench" for testing). This represents the minimalist system which I
can build to order.
Please
note however that being based in the UK I have to pay European prices
for materials and since I am building one offs I don't get any savings
in materials costs i.e. I pay just the same as you do when buying
transformers from Sowter or
Lundahl, or components from RS and
Farnell. So if you would like me to build you a Zeus system, it will be
suitably and reassuringly expensive.
2008 - I prototyped a number of internal DAC
upgrades for my Oppo DV-980H optical media player. I also started full-time employment
as a technician in the Department of Physics at Imperial College London.
2022 - Finally get everyting together and now our 5.1 system is entirly Zeus based. The Left and Right rear channels use the Zeus-35 amps I built back in 1995.
2023 - This year so far has been experimenting with
singel-ended output configurations. I am still working for Physics at ICL.
See the discussion over at the DIYaudio Forum...
Zero Feedback Impedance Amplifiers
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