[Vintage-Audio] Re Super Thin Dynaflex

[Robert Nickels]

Duane Fischer, W8DBF wrote:
> At what point in time did the record changer and turntable companies 
> change the tracking weight from 3 grams+ to about 1 gram?
This is an interesting question Duane, because I've been working on a 
turntable that it is said paved the way for this transition.  I refer to 
the Weathers turntable, which was based on the Capacitance Or FM 
Cartridge developed by Paul Weathers at his comany, Weathers Industries 
of Barrington, NJ in the 1950s.  Let me quote (somewhat edited by me) 
from a website I found that discusses this topic rather well:

His theory was, the less work the stylus must do, the more accurate the 
pickup can be. In magnetic, dynamic and piezo-electric pickups the 
electric signal is generated by the motion of the stylus itself, which 
requires a certain minimal bulk. Even with the most careful engineering 
a vertical pressure of four to eight grams was necessary to make such 
pickups work properly, and the moving mass of the stylus must remain a 
measurable quantity. If you could design a pickup in which the signal 
voltage was already there, and the motion of the stylus would merely 
modify it, then you would approach the perfect pickup.

Literally hundreds of patent applications have been filed on such 
designs, and a few such pickups have actually been manufactured. The 
most successful of them is the Weathers, which is called a "capacitance" 
pickup or an "FM" pickup because the stylus causes frequency deviation 
of an oscillator that is demodulated to produce the audio signal.  The 
Weathers pickup consist of a fixed metal plate  and a parallel 
free-floating plate separated by a tiny air gap. The floating plate is 
attached to the stylus. As the stylus traces the wiggles in the groove 
of a spinning record, it causes the floating plate to flutter toward and 
away from the charged plate.  This capacitive change is demodulated to 
produce left and right channel audio. 

The author of the website cites several advantages of the 
Weathers..."Since it tracks at a pressure of only one gram, it wears 
both records and styli much more slowly than any other pickup available 
at the time.  The moving mass of the stylus has been reduced to the 
point where it is scarcely measurable, which means that the frequency 
response is practically unlimited - the Weathers has tested out to 
30,000 cycles."

I can't verify all this but I can say that the Weathers I have sounds 
good, thankfully after all the years the stylus is intact, which I'm 
sure is pure unobtainium today.  Ironically, a surplus dealer in Omaha 
has a few similar turntables (not all in working condition) if anyone 
would like to take a look: 
http://www.surplussales.com/Equipment/Audio.html  (the separate basswood 
tone arm and demodulator unit for sale for $350 are identical to mine).

The simplicity of the tonearm itself is striking - it's nothing but a 
piece of basswood with a basic gimbal mount attached.  The tonearm rest 
uses a magnet to hold it in place.   The stylus connects to the 
headshell via two pairs of slide-in spring contacts, an there's another 
set of similar contacts where the cartridge leads attach to the 
electronics.  The FM demodulators are each contained in an aluminum can 
(looks like an IF can) that is potted with some waxy goop, and plugs 
into six PC terminals.  That's a lot of series connections that have to 
all work in order to get output, but I think cleaning and fighting 
intermittents has produced a working unit.  The drive mechanism is also 
unique - nothing more than a tiny synchronous motor and a soft rubber 
drive wheel driving the inside surface of the very light aluminum 
turntable.  It's a unique design throughout - even the power is turned 
on and off by a lever that tilts a sealed mercury switch.

So that's my answer to the 1 gram trackin question - Paul Weathers did 
it first and the rest figured it out later.

73, Bob W9RAN