JUNE, 1986


RECORD COLLECTORS and audiophiles do not go in much for banner-waving demonstrations; but if they did, a sizeable minority might be found with banners proclaiming something like "Nostalgia Rules OK". They would be out of step with the majority, and might even be accused of `walking backwards', but the appeal of old recordings (and in some cases old equipment) can be very strong.



Where vintage recordings are concerned there can be traced a lineage of unique performers and performing techniques which stretches all the way back to the turn of the century. It is hardly surprising that many of us like to savour again-even through a scratchy haze-the recordings of these Golden Age singers, pianists and conductors instead of just reading contemporary accounts of them. All the major record companies have always understood this nostalgic urge and have periodically dipped into their archives to reissue selected classic recordings as LP transfers. Sad to say, these LPs have been variable in quality. Successful restoration of old 78rpm records, or even early LPs, demands a great deal of dedicated skill and specialized equipment-and is even then restricted by the quality of the best original version that can be discovered.


Fortunately, the most recent wave of such reissuing has been inspired by the desirability of offering new owners of CD players as wide a recorded repertoire as possible. Thus the companies have started delving into the recent and not so recent past to bring us key recordings by Furtwangler, Walter, Klemperer, Szell, Ansermet, Barbirolli, Batten, Backhaus, Haskil, Callas, Ferrier, Flagstad and others. At the same time, new digital processes have made it possible in the best cases to refurbish these older recordings with a standard of sound quality which surpasses what would have been heard on contemporary players when the recordings were new.


A supreme example of this application of the latest technology (plus the essential ingredient of informed enthusiasm for the music) to restoring old recordings can be heard in the series of 26 programmes called "Jazz Classics in Digital Stereo" currently being broadcast on BBC Radio 2. The series is transmitted at 4.00 pin on Sundays and has reached about the half-way mark as I write. The presenter is Australian sound engineer and jazz expert Robert Parker, and he has performed marvels of enhancement on jazz recordings dating from 1917 to 1947, including simulated stereo and reverberation. The BBC have issued three LPs and musicassettes compiled from Robert Parker's transcriptions, and three Compact Discs are to follow each containing four extra numbers.


Playing Old Records

For do-it-yourself `restorers' the audio industry has begun to provide helpful hardware. For example, such diverse turntable manufacturers as Dual and Pink Triangle have recently brought out turntables with the 78rpm speed re-introduced after decades of neglect. Most of the larger pickup cartridge manufacturers still market 78rpm type replacement styli for some of their cartridges (having the required coarse-groove nominal tip radius 63µm or 0.0025 inch). This is the easiest route towards playing 78rpm records in the modern world, though some dedicated collectors still use steel or thorn needles in acoustic soundboxes! To be honest, a set of diamond styli with graduated tip sizes (such as I. had available when I used to teach Tonmeister students) is required for optimum playing of different 78rpm labels and vintages.


There are also the questions of scratch suppression, filtering and correction for the widely varying equalization curves used over the years. Scratch noise suppressors have been marketed by SAE, Garrard and others but may be difficult to find in the shops. Filtering can be tackled with some of the better designs of graphic equalizer.


However, the re-equalizer unit reviewed here is the first really dedicated device I have come across which provides convenient matching for nearly all the important equalization curves met in practice. It was sent to me by its designer Michael N. Stosich who tells me that it is not only selling well in the USA but is attracting attention in Europe too.


Basically it adds on to any modern amplifier the EQ switching facilities which used to be fitted on some of the more sophisticated amplifiers of the 1950s. (I still have in my loft the plugin adaptors for both Quad and Rogers amplifiers.) Wisely the designer has not tried to build his EQ networks into a 'front end' device where problems of matching, noise and overloading could so easily arise. Instead, his re-equaliser is designed like most of today's add-on processors as an active unity-gain unit to be inserted between the preamplifier and power amplifier (where these are separate units) or in the tape recording and monitoring loop provided on most integrated amplifiers.


Pairs of phono-sockets are fitted on the rear panel for making these connections. No sensitivity rating is quoted, though a conventional 250-500mV input/output level can be assumed. The maximum input level is given as 3.5 Volts, which should allow sufficient headroom for even the most extreme boost characteristics met in replaying some old discs.


Of course, the Re-equalizer is so called because the signals it receives will already have been `equalized' in passing through the normal IEC/RIAA circuitry in the pickup input of the amplifier. The circuit, comprising four operational amplifiers on two integrated circuits, first applies an inverse RIAA curve and drops the mean level by 32dB before applying the various switched curves-so that it is really introducing the difference between the standard RIAA curve and the older characteristics.


The front panel has a Bypass switch at the centre, for playing normal modern LPs or other material. The unit is then completely out of circuit. In the `In' position the two channels are combined, i.e. mono. On either side are the large rotary six-position switches for bass and treble EQ respectively-giving a total of 36 permutations. The designer has helpfully listed in his instructions booklet about 90 different record labels (78rpm and early 33s and 45s) with the recommended switch positions to be used. On the discs I tried, he seemed to have got it right every time, but, of course, there is no law against experimenting with either the bass or treble switches (plus your amplifier rumble and scratch filters, plus tone controls) to get the sound which pleases you best.


The actual unit is housed in quite a small metal box (240 x 40 x 140mm) with the mains transformer bolted on the outside for minimum hum induction. I was supplied with a 240V unit at my request, though the European model will normally be 220V. As supplied the unit is mounted on a full 19inch (483mm) slotted rack panel which will be ideal for professional installations. Alternatively there is a walnut case available for an extra $85.


How It Performed

For a start, although the booklet includes frequency response graphs for the various switch combinations, I decided to find out just what exactly the switches were doing by feeding in a constant voltage signal at a harmless 100mV and plotting the output on my B&K pen recorder. The results are shown in figs. 1 and 2.


Taking the bass switch first (fig. 1) it will be seen that I had set the treble switch at RIAA throughout (giving the flat response from about 1kHz upwards that we would expect). I have numbered the six available bass switch settings from I to 6. No. 1 is the "Flat" position introducing reverse RIAA bass correction and intended for use with the majority of acoustic 78s which had no EQ! Nos. 2, 3 and 6 provide three increasing levels of bass boost from turnover (3dB) frequencies of 200, 300 and 700Hz respectively. No. 4 is the "RIAA" position exactly restoring the standard EQ for playing modern LPs and some post-1935 78s, etc. Finally, No. 5 gives reduced bass to suit, for example, early American Columbia LPs.


Turning to the treble switch (fig. 2) I have here set the bass switch to RIAA (equivalent to Bypass) and position No. I is again "Flat", meaning no EQ. Nos. 2, 3 and 4 bring in treble roll-off at respectively - 5, - 10 and - 12dB at l OkHz. No. 5 is the RIAA position for most modern records, and No. 6 is NAB for early American Columbia LPs, etc.


Since all these curves (which agree very closely with the maker's graphs) are in effect added to the normal RIAA EQ built into the pickup amplifier, I have translated the plots of figs. I and 2 to show the overall change to be expected `as seen by the disc' (see figs. 3 and 4). These do make clearer the different degrees of bass boost and treble cut available. The amounts of frequency control may seem subtle or horrendous depending on your point of view. For my part, on subjective listening it was a great boon to be able to go straight to the maker's recommended setting as a starting point. Then, if the sound still seemed bass-light or over-shrill, I could make one or two adjustments and reach a satisfactory bass/treble balance.


Technically, the unit is clearly well built using high-grade components, and should give a lifetime's service. The brief specification was checked out as 100% accurate (see Table) and so reflects credit on all concerned. The unit is aimed at what is surely a diminishing market. However, if you feel the need to replay or transcribe vintage records from any era, it could be a most welcome acquisition.




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