The Mapleson Cylinders - Program Notes
|The Mapleson Transfers|
|Primary Transfers and the Public Service Tape: 1981-82|
Probably the easiest way to describe the Mapleson transfers is to describe a typical work day. David Hall and I would take one of the seven original boxes the Maplesons were packed in, and work on it until the box was completed. The cylinders were packed randomly in the seven boxes; there was no program or performance order. To minimize handling, we took them as they came out of the box, often not knowing what was on the cylinder until we played it. Prior to playback, while still in their original containers, the cylinders were allowed to warm up under a 40-watt soft light. Each cylinder was examined under the microscope, and groove size and description noted. If cotton fibers remained on the cylinder from the box linings, they were blown off with an air gun. A treatment of LAST (Liquid Archival Sound Treatment), prepared especially for the cylinders by Ed Catalano, was applied if needed. The cylinders would then be placed snugly on the mandrel, but not forced.
The reproducer comprises a modified Rabco SL8E tangential tonearm, capable of tracking 100 to 200+ lpi, equipped with a Stanton 500-AL cartridge. The tonearm is driven by the groove, except when a locked or deformed groove is encountered, at which times a battery powered servo motor takes over. The mandrel is solid brass, approximately the same size as an original Edison mandrel, driven by either an Ampex two-speed hysteresis motor or a servo motor, and is mounted off the body of the reproducer, thereby eliminating any mechanical vibration. The motor is belted via a pulley (gated for the standard cylinder speeds) to a very heavy brass wheel, with the mandrel attached to it (see Figure 3).
After the correct stylus was fitted (often, many would be tried), the vertical and lateral components of the signal would be monitored. The cartridge was wired to a Mallory switch, then to a transformer-based Stanton 210 preamplifier in the linear mode wired to a patch bay. This setup allowed monitoring of the left, right, lateral, or vertically modulated groove. (One soon learns that those who insist there is no lateral modulation in a cylinder groove simply aren't listening.) The signal arrived at the patch bay at a level of--20 VU. It was then elevated by U.R.E.I. LA-3A amplifiers. Level was adjusted to peak at a maximum cylinder modulation of 0 to +3 dB, referred to NAB standards.
The next step in the chain was the Packburn Transient Noise Suppressor. Space does not permit an in-depth discussion of this device (for a detailed account, see the review in Stereophile, V/8 [October 1982], 8ff.), the chief contribution of which is to eliminate tricks, pops, cracks and other transient noises. When the signal left the Packburn, it arrived at the Owl 1 Restoration Module, used here as a low-end (20-60 Hz) and notch filter. The thump and rumble associated with most cylinders is either mechanically induced by the original machine or occurs as a result of out-of-round cylinders. This is easy to see with a spectrum analyzer. After the thumping was eliminated, the ticks and pops removed, the signal then went into a pair of U.R.E.I. 565 "Little Dippers." These filters were usually set as low/high-pass filters with an 18 dB per octave slope.
Throughout this whole process each step of the way was monitored on the BaDap and the Leader oscilloscope, checking resonances, polarity, etc. Unusual problems, as well as the final stylus selection, were noted by Mr. Hall. In all these steps, no boost or curve equalization of any kind was added or imposed. At this point, the cylinder, usually reproduced at 184 rpm, would be recorded onto 1.5 mil magnetic tape at 15 ips, on an Otari MTR 10-2. All tapings of each cylinder were verbally slated. Each cylinder was transferred completely flat, then with filtering, and followed by all previous 78 rpm and LP transfers, giving us the recorded history all in one place. The tapes were then collated alphabetically, opera by opera, and pitched to the printed music. Every effort was made to achieve accurate identification of casts and performance dates. We have compiled and edited a history of the Mapleson cylinders, with complete technical information, which is now available at the reference desk of the Rodgers and Hammerstein Archives. Analysis of some cylinders has been recorded onto video cassette for future examination. The initial transfer process began in mid-May 1981 and lasted until late June.
After completion of the transfer process onto thirty-one reels of tape, cassette copies were made for exact identification and pitching, following which a pitch-corrected working master was prepared, edited into alphabetical sequence by opera title and generally in performance order within each opera. By the end of 1981, a research tape was available for on-premises audition at the Rodgers and Hammerstein Archives.