Audiophile Preamplifier Line Stage

Offering a new experience when introduced into the Naim range of preamplifiers, the 821s address two key problems inherent in the Naim 321 design:

Naim 321 stage- key problem No. 1: Too much gain

The original Naim Audio 321 stages simply have too much gain, a throwback to the days of low-output cassette decks and tuners. The much higher output from CD players tends to overpower the Naim 321 stage, necessitating the use of heavy global feedback in order to exercise some control over the proceedings.

The use of global feedback of this magnitude, as employed in the 321 circuits, introduces a whole new set of problems which are not easily cured by simply adjusting a couple of resistors to bring down the output level.

Whilst it is possible to adjust the level of gain in this way, the sound quality of the 321 circuits, its character, alters according to the feedback applied to the devices - mostly in a negative direction.

Naim 321 - Key problem No. 2: Hiss

The characteristic hissing from the 321 circuits, when added to the main amplifier residual noise, can certainly be intrusive - especially when using sensitive loudspeakers.

The 821

Fluidity - the 821 module is completely free of global feedback and has a fluidity lacking in the 321s.

Control - The lower gain of the 821 means greater control over the volume levels - no longer will you have the ear splitting cacophony once the control is a degree or two from zero.

ALL signals passing through the preamp are handled by the 821. This means that the performance of every piece of connected equipment is enhanced to the same degree. And the hiss, predominant from the Naim circuit, is reduced to the merest whisper after fitting the 821 modules.

821 design and build quality

Developed over many, many hours of listening to a variety of circuit configurations and transistor designs against the sound of valve amplifier stages of many different configurations. Although many valve stages presented a beguiling soundstage, there was still something not quite right about the sound of a system when introducing even the best of transistor designs into the equation. A valve stage was considered but the non-availability of tubes of a consistent quality meant that one example of an amp stage would invariably sound quite different to another - not good for the reputation of any designer.

Thus began the search for a reproducible line stage and instead of relying heavily on highly technological routes to sonic 'nirvana', a return was first made back to valve circuits. Would it be possible to emulate the valve circuit using some high gain transistors?

The answer came in the form of the transconductance circuit first used in the Avondale G1 preamplifier, and now adapted in simpler form for use in the 821 modules. Having no overall feedback, these modules perform almost exactly as a valve stage would - with only a tiny element of second harmonics - well below audibility.

The stage began to evolve until it became both very sophisticated and consistent in sound quality. Employing many refinements, and using some very exotic components initially produced for the Royal Air Force, the 821 had the solid consistency needed to be manufactured in quantity.

It is necessary to hand select critical parts during the building of these modules to achieve this exceptional level of sound quality.

Hand crafted in matched pairs, the 821 modules have an ease when going about their task which other circuits fail to match. The unique local feedback circuit takes care of the transients as though they were not there at all.

Tiny details, meanwhile, appear from the mix and provide the listener with a fresh insight into their favourite music, without the grain and loss of fluidity normally found in transistor designs.