A rare find and true reference phono preamplifier.The Groove
RIAA stage is
the result of over 10 years R&D into disk replay. In developing the Eikos
CD player, Tom argued that as long as the voltage regulators supplying the
board were noisier than the quietest passages recorded, and their transient
response time was slower than the devices were capable of, there was no point
in improving the circuit topology until these fundamental problems were solved.
Two years later, he had developed the Lithos voltage regulator, a milestone in
musical reproduction. The device is 53 times faster, 1000 times quieter, and 5
decimal places more accurate than the previously 'best' regulators available.
Thus was laid the foundation for The Groove phono stage.
The Groove is a dual mono design using one Lithos 7
regulator per side to supply power to each mono signal path p.c.b. The
regulators are powered by a dual mono
mains power supply. Channel separation is therefore limited only by the
specifications of the cartridge used. All resistors are Holco precision metal
film. At the front end, Tom has used very low noise I/Cs (less noise than a
50-Ohm resistor). This stage is followed by a passive RIAA EQ circuit. The
third stage is an ultra linear gain amp; around this he has placed the active
lower frequency filter to roll off subsonics. The fourth stage is the output
stage, which is capable of driving several meters of interconnect.
The case, if made of any metal other than copper, would
have a deleterious effect on the sound quality, as field effects of even
non-ferrous materials interfere with electron flow. For this reason, the
casework is of Perspex, a material with no inductive capacity.
Since its launch in the UK, it has become the industry
standard. The Groove can be upgraded to the Plus spec.The Groove+
is a Groove
with a severely uprated power supply (larger transformer, increased smoothing
caps, and an extra layer of Lithos regulation between the standard unit's
internal daughter boards and the mains), which makes a substantial difference.
The four layers of isolation allow a -180dB noise floor. The mains pcb has been
replaced by the Lithos 6, a complex class A regulator. Its outputs then feed
the dual mono Lithos 7s on the signal pcbs. The external mains supply box
contains a 70 watt transformer designed and manufactured in house. The
transformer has an electrostatic screen to remove any RF noise, then rectified,
smoothed, and regulated before leaving the box and heading for the Lithos 6.
The ultra-low noise and distortion of this product provide audiophiles with the
greatest possible dynamic range and resolution available.
"The power supply makes instruments more solid, but
above all, more natural. It brings the music presence" says Roy Gregory in
Hi Fi+. Truly fabulous.
Sixmoons Blue Moon Award: