Robert, I'm not quite sure what's going on in your reproducer
experiment. The needle mounting cavity in the Victor ortho reproducer's
needlebar is nothing special, it's merely a triangular bore with a setscrew
located approximately halfway along the length of one of the flat sides to
clamp the needle into the opposing "V" trough of the bore. But I can guess
at several things:
(1) You could have some dirt inside and at the very end of the bore that
is causing the needle to not seat firmly into the V groove when you insert
it fully. This will cause some decoupling of the needle with the needlebar.
When you don't insert the needle fully, you don't engage the dirt which then
allows the needle to seat into the V more tightly.
(2) You don't mention which direction the loudness changes. Inserting
the needle less fully into the bore will result in it's sticking out farther
which changes the mechanical "gain" of the needlebar system. The longer the
distance from the needle point to the pivot of the needlebar, the less
loudness you will get. Just a small change here can be audible.
(3) If you are inserting the needle just enough so that the thumbscrew
just engages the blunt end of the needle, you are not securely clamping the
needle against the V groove. As it wiggles, the needle itself will lever
against the thumbscrew as a fulcrum and flex against the V groove, causing
some error in transmitting the vibrations to the needlebar. This will cause
a loss of volume.
Any of the above scenarios will change the volume as well as change the
frequency response and may cause distortion which can be interpreted as
"improved" high frequency response.
Greg Bogantz
----- Original Message -----
From: "Robert Wright" <[email protected]>
To: <[email protected]>
Sent: Friday, August 28, 2009 5:00 AM
Subject: [Phono-L] An interesting observation
Been meaning to post this for a few days now...
I was recently
spinning some discs on my Victor Orthophonic suitcase model, and it
dawned on me to try something out. I slipped a new needle into the
shank, and I pulled it back out maybe a millimeter or so, just enough
to keep the blunt end from resting against whatever it rests against
before tightening the thumbscrew. I immediately heard a noticeable
difference in volume (maybe 1 to 2 dB), slightly wider frequency
response, and most significantly, an openness (for lack of a better
word) I'd never heard before on any windup phono. It seemed like all
this time, something was slightly constricting the diaphragm, just like
pretty much every windup phono I've ever heard in person, and suddenly
there was a whole new freedom to the sound pouring out of it.
Has anyone else ever tried/noticed this? Mr. Bogantz, is this my
imagination?
Best to all,
Robert
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