Re: arsclist Thanks and Cactus Needles

[Graham Newton <gn@xxxxxxxxxxxxxxxxxxxxx>]

Western Folklife Center
Steve Green wrote to arsclist@xxxxxxxxxxxxxxxxxxxxxxxx:

> I've been very interested in the Speak-O-Phone Company that made
> personal disc cutting machines and aluminum alloy discs back in the
> 30s.  
> Because of the soft aluminum used in the discs, steel needles are not
> appropriate for playing back the records.  Instead needles made of
> cactus thorns, bamboo, or other fiber material are needed in order to
> avoid damaging the record.  At least, that is what the company stated
> on some of its packaging and I assume that audio archivists today do
> in fact use some sort of soft needle

Bad assumption.

In the days of the Speak-O-Phone Company, "needles" were steel, and
"needle" pressures were measured in ounces because of the heavy and very
non-compliant nature of the phono cartridge and arm that carried them.  

I actually have an RCA Victor "Victrolac" sleeve that says "Use 3 to 4
oz. needle pressure, never more than 5 oz.", an admonition that would
rapidly be fatal to the soft aluminum disc, and it was for this reason
that the fibre needles were issued.  

With today's stylus pressures measured in grams (typically 3 to 5 grams
for coarse groove records) there is no need, or benefit to be had, by
attempting to use a fibre stylus.  Yes, I suspect there would be some
nominal wear by playing the disc, even with gram-pressures and a high
compliance stylus/cartridge, but no more than the normal accumulation of
wear from the physics of rubbing two objects (stylus and groove)
together. 

Further, to attempt to use a fibre "needle" you would have to resort to
an old phono cartridge with a set-screw for holding it.  It would
doubtless be heavy and very low compliance, which would further damage
what is already a fragile artifact.  

My comments apply to ANY old phonograph recording... attempts to play on
"vintage" equipment with the mis-guided idea that "thats what was
intended" will result in the rapidly accelerated demise of the object.


... Graham Newton

-- 
Audio Restoration by Graham Newton, http://www.audio-restoration.com
World class professional services applied to phonograph and tape
recordings for consumers and re-releases, featuring CEDAR processes.