The latest incarnation of the unique Avondale Audio zero feedback,
single ended, transconductance design.
The circuit, designed by Les Wolstenholme, is a revised version of
that used in the well-known and revered 'Graduation One'
preamplifier. Here, it has been adapted so as to be suitable for
owners of Naim Audio preamplifiers who desire the highest level of
musical clarity that these excellent preamplifiers can achieve.
In considering the output levels of most modern source
components, the 821s provide more of a match than the over-
sensitive 321 modules fitted to the Naim pre-amps. In reducing the
821 overall gain to around three, the user then has finer control over
the volume level.
The high gain and heavy feedback of the original 321 modules
produces an intrusive ‘hiss’, audible in some cases from the
listening position. The 821s have no such problem - they are
almost totally silent and the bonus of having no global feedback
means that transients are handled with consummate ease allowing
a deeper insight into the music.
Drawing upon a wealth of knowledge and experience Avondale
Audio has taken this deceptively simple circuit to an audibly higher
plateau of performance. A few of the immediate upgrades in the
layout and materials are:
· Thick 2mm PCB substrate with gold plated pads
· Avondale’s unique ‘litz’ PCB tracking in the signal path
· Double thickness copper track for reduced impedance
· Revised component position results in shorter signal path
· Large film capacitors used in the signal path
· Extremely high grade ‘Bulk Foil’ resistors
· Nichicon KZ and Panasonic Electrolytic Capactors
· Premium polystyrene and polypropylene capacitors
· Matched transistors for each pair
Made for the Naim NAC32, NAC32.5 and NAC72 models as well
as our own Avondale 821 Preamplifier.