The Talking Machine Forum — For All Antique Phonographs & Recordings

gregbogantz wrote: Although there may have been variations in the weights of the various components in these inertia arm systems during their several years of manufacture, the several in my possession I have measured and they produce the same tracking force as the earlier straight arm in my RE-75 which is also about the same as that of the Victor acoustic orthophonic reproducer at around 150 grams.

You mean LATE straight arm, don't you? The counterweight was made heavier towards the end of production of the first series Micro-Synchronous Electrola. Earlier machines tracked rather heavier, and the hollow arm Electrolas of 1926, 1927 and 1927 tracked heavier still. late examples of. The inertia arm, those dating after 1933 or so, tend to track at a lighter weight than the arms used on the RE-57 and Radiola 86 because they were designed for use with an improved pickup, with a combination of viscoloid and spring damping. Of course these late pickups are pretty thin on the ground, as combinations were not selling all that well in 1934 and 1935. A pickup arm that I own which was salvaged from a High Fidelity Victrola R-99 (the fellow from whom I purchased it sold the amplifier and speaker to Asia and broke up the otherwise clean cabinet ) tracks at 95 grammes.

Note that the Victor engineers found that the more heavily counterweighted tone arm of late 1930 tended to increase record wear, particularly on heavily recorded discs for the incompliant stylus would tend to ride up to tfragile tops of the grooves in the loud passages. This the Inertia arm corrected. Record wear is actually appreciably lessened with the use of this improved arm as opposed to earlier, less compliant units, most particularly the crude, rigid, poorly counterbalanced GE pickup arm used on the Radiolas 47 and 67.

By the way, Mr. Bogantz do you still offer your excellent diaphragms for Diamond Disc machines? I purchased a machine with one of your rebuilt reproducers on it some years ago and found it to be really excellent.

Vanya, you are absolutely correct in noting that too LITTLE tracking force can be more detrimental to record wear than having too much. If the tracking force is insufficient to compensate for the low compliance and high moving mass of the stylus assembly, the stylus may leave contact with the groove wall momentarily during high velocity, high amplitude modulation. It then will return to contact by smashing into the groove wall. The impact of the mass of the stylus assembly slamming back into the groove wall will impart momentarily HUGE pressure at the point of contact which will result in creation of a divot, compression, scratching, scarring, or other physical deformation of the groove wall which will result in permanent damage to the wall. This behavior is known as "mistracking".

Too many users of modern playback equipment seem to feel that they can get away with the minimum tracking force listed by their cartridge manufacturer. If a range is quoted as from 0.75 to 1.5 grams, the customer feels completely confident in operating the pickup at .75 grams. In fact, that force may be adequate only for playing classical chamber music records which have very little recorded audio level. When that low force is used to play loud jazz or rock records, the stylus will likely mistrack and cause permanent record damage. Had the user opted for the 1.5 gram operating force, he would avoid the destruction of his louder records.

Thanks for your kind words about my DD diaphragm. Yes, I have available diaphragm designs for the Edison DD reproducers as well as for the Diamond A, B, C, and D models and for the L, M, and O models. You can hear them in operation in several of Valecnik's YouTube videos. Bruce has several of my designs, but you'll have to ask him which ones are in use in which of his videos. PM me if you are interested in more info on the diaphragms. All new customers are sent a copy of my reproducer rebuilding instructions which I think you'll find are very complete. This document also includes hints on how to "tune" the clamp ring on the reproducer to modify the sound to your particular taste.