Tom Evans Audio Design -
Groove+ phono preamplifier
The Groove phono stage is the result of over 10 years of R&D
in vinyl replay. In low level phono applications it is imperative
that the voltage regulation supplying the gain circuit is not noisier
than the quietest passages recorded, and that its transient response
time is at least as fast as the devices in the downstream circuit.
There's not much point in improving the audio circuit when the
voltage regulation that supplies it is anything less than superb.
Now Tom Evans has developed the Lithos voltage regulator, a milestone
in power supply voltage regulation, and of course, in musical reproduction.
The Lithos is 53 times faster, 1000 times quieter, and 5 orders
of magnitude more accurate than the 'best' regulators available.
Thus, Lithos voltage regulation, is the foundation for the stellar
performance of The Groove phono stage.
The Groove is a true dual mono design. Channel separation is
limited only by the specifications of the cartridge used. 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.
Finally, the output stage is capable of driving several meters
The chassis for The Groove is made of Perspex, an acrylic polymer
that is tough, offers excellent mechanical isolation properties
from microvibration and has no inductive capacity. These characteristics
combine to give the Groove its extra quiet performance.
The Groove+ is a Groove with a substantially upgraded power supply
including a larger transformer, increased capacitor rating, and
an extra layer of Lithos regulation between the standard unit's
internal daughter boards and the mains. The four layers of isolation
deliver a noise floor of -180dB. "The power supply makes
instruments more solid, but above all, more natural. It brings
the music presence," says Roy Gregory of Hi Fi+ magazine.