BECAUSE THE Discwasher Group distributes Telaro's "direct-to-disc" recordings, at a hefty $16 per disc, one might have inferred that the similarly high-priced Denon records Discwasher is importing from Japan ($14 suggested list) are products of the same process, but they are not. Denon, in fact, inserts an additional stage into the usual tape-to-disc processing cycle and, far from losing quality thereby, has come up with what many listeners consider the finest sound on discs.

Moreover, these are not gimmicky samplers or collections of demonstration pieces: Denon has assembled a substantial catalogue of important works in really distinguished performances. One splendid example is the two-disc set of Beethoven's Ninth Symphony, performed by the Czech Philharmonic under Vaclav Neumann, with four very good Czech soloist and the Prague Philharmonic Choir (OB-7333/7334ND). It is a first-rate Ninth - one of the best things Neumann has done on records - and never has so much of this great orchestra come through in a recording. There is phenomenal clarity of detail in every section, and yet no watering down of the rich, warm texture.

The dynamic range, absence of distortion and overall sense of realism, here and in the other Denon recordings I've heard, are quite without parallel in my listening experience, and everything seems directed solely and effectively toward the goal of naturalness rather than sensational effect. In the Ninth, the quality is the more extraordinary because the recording was not a studio job, but was taped in Tokyo's Metropolitan Festival Hall, where the performance was given in concert (before an incredibly quiet audience) on December 3, 1976.

Denon (which makes equipment as well as recordings - its turntables are also imported by a Discwasher company) calls its process "PCM," for Pulse Code Modulation.This is a digital (computerized) technique, derived from space technology; the layman may not entirely understand even the simplified explanation Denon offers of how PCM works, but no one can miss the very clear point that it does work, and live quality of these recordings is no less impressive in chamber and solo works than in orchestral material.

Most of the 70-odd titles in the initial release, in fact, are in the chamber music category, and this itself is a significant indication of Denon's serious musical purpose in developing its new technique. There are string quartets, trios, quintets and other works by Beethoven, Schubert, Haydn, Mozart, Schumann, Janacek, Bach, Telemann. Tchaikovsky is represented on the label so far not by any orchestral blockbusters, but only by his eloquent Serenade for string orchestra and his seldom-heard Piano Trio.

A glance at Denon's roster of performers - the Suk Trio, the Smetana Quartet, harpsichordist Zuzana Ruzickova, Jean-Pierre Rampal, the Jean-Francois Paillard Chamber Orchestra, et al. - and their respective repertoire might lead an experienced discophile to assume that most of the material was leased from Supraphon and Erato and that some of it has circulated here on various budget labels in the past; but this would be another inaccurate inference. Like the Ninth and Maria-Joao Pires' complete series of the Mozart piano sonatas, most of the recordings were taped in Tokyo very recently by visiting European musicians; others were made in Prague, Paris and other European cities as co-productions with various European companies - always using Denon's special PCM equipment and with a Denon production team from Japan taking part in the sessions. (Dates and sites of the sessions are given on the jackets.)

Outstanding examples of remakes are those by the Suk Trio of Beethoven's "Archduke" Trio on OX-7035 and Schubert's B-flat Trio on OX-7043, the Smetana Quartet's coupling of the two string quartets by its composer namesake on OX-7049, and Rampal's performances of the Telemann Fantasias for solo flute on OX-7007. The Suk Trio's earlier recordings of the Beethoven and Schubert works (the former adjudged the choice version of the "Archduke" only last fall in these pages) have just been deleted by Vanguard.

Of special interest outside the remake category are a pairing of Mozart's two greatest string quintets (K.515 in C major, K.516 in G minor) by the Smetana Quartet, with Josef Suk sitting in as first violist (the great violinist's only recording as violist, as far as I know, OX-7089) and a stunning account of the Mussorgsky/Ravel Pictures at an Exhibition by the Tokyo Metropolitan Symphony Orchestra under Louis Fremaux (with Ravel's Pavane as filler, OX-7072). The youngest of Tokyo's several orchestras sounds like a world-class ensemble in the Pictures , and Fremaux certainly has the measure of the piece; instead of just bigger and bigger climaxes, this production (which is by no means deficient in that respect) thrills with its sense of immediacy. I would question only the decision to break for turnover between the two sections of "Catacombs" - though this is not as much of an interruption as one might think.

The pressings themselves (by Nippon Columbia) are every bit as flat and quiet as claimed; I've encountered nothing resembling warpage, no hiss, no pre-echo. I did run into one very audible blister across three or four grooves in the finale of the Mozart G-minor Quintet, but, from the appearance and performance of the several discs I've received, I'd almost bet this was Denon's entire quota of mishaps for the year.

Among these discs, only the Beethoven Ninth is provided with annotation - and that is in Japanese only. Perhaps English notes will be supplied with future releases, but even without them these exceptional discs seem fully worth the steep price asked, if the buyer really cares about sound quality and has the equipment to get the most out of his records. Denon is certainly putting the most into them.

(So far Denon records have been sold in audio shops rather than records stores, and the only shops in this area which carry them at present are the several branches of Audio Associates, whre they are priced at $12. Discount Records will begin stocking Denon in the near future.)