The exquisite Duo-Vox Diamond Disc reproducer, an insight.
The beautifully designed Duo-Vox phonographs, provided by the Bush and Lane
Company, were capable of playing
lateral 78's and vertically cut Diamond Disc records. This was done
with a very well designed tone arm that had TWO
reproducers on it! More info on the lateral reproducer later. Today,
I want to concentrate on the beautifully engineered
Diamond Disc reproducer as shown below.
One notices immediately that the cork camping disc is more of a ring than
a disc. The diaphragm itself is suspended in the body by simple rubber
gaskets. The diaphragm is composed of a dense fiber impregnated with
phenol resin. The cork damping ring is adhered to the diaphragm. And,
THAT is the END of the "normal" design keys! Check out that stylus
suspension boss and associated springs!! Before I describe to you
how over engineered the stylus setup is, I will describe to you the delicate
nature of the diaphragm link. The diaphragm link is NOT attached
to the diaphragm at all! Instead it is held against the backside of
the diaphragm by the spring tension of the stylus.
On the backside of the diaphragm, the end of the diaphragm link sits atop
a felt washer, sandwiched above a LEATHER washer which actually
contacts the back of the diaphragm! It gets weirder!
Looking at the suspension setup at this angle, I can further explain. The
stylus has a "C" clip in front of it, which creates
a tension "loop" with the diaphragm and diaphragm link. Essentially,
the stylus link is being pulled UP with the same force
that derepresses the center of the diaphragm DOWN via a reacher bar. Confused?
It gets worse!
Surrounding the diaphragm link is a black feltoid washer which is retained
by the reacher bar. Now, what looks like a diaphragm
under the black felt washer is NOT. It is actually a fiber retaining
cup which sits atop ANOTHER black feltoid damper washer...
which ultimately sits atop the diaphragm! Insane, no?
Technically, it tracks the Diamond Disc record the same as an Edison diaphragm.
The bass response from this is nothing
short of amazing. Although heavily dampened, and under high tension,
the diaphragm produces a very sweet and natural tone.
MUCH BETTER than a Brunswick Ultona, and a lot more elusive!
More info to be added later. Thanks for reading!