Re: [AV Media Matters] Transcript Discs

[Matthew_Davies@screensound.gov.au]

Graham Newton's subsequent post has suggested some further relevant info
required , viz :-

Cetrimide is a generic name for n-cetyl ammonium bromide and should be
available from chemical supply companies. It's a surfactant (wetting agent)
and also has anti-fungal properties.

Eucalyptus oil is a mild solvent which we have observed to work well on all
manner of sticky, greasy or oily contamination. Apply with a cotton bud, a
bit fo gentle rubbing wil generally shift chinagraph marks, adhesive
residue, etc. While I always recommend testing on a non-critical part of
the disc e.g. the run out groove I am not aware of any problems with
Eucalyptus oil dissolving lacquer or other common disc materials with the
exception of gelatine.

HFE's (hydro fluoro ethers) are good solvent based cleaners for lacquers,
and can be used with care on cracked or flaking lacquer discs.  HFE 7100 is
a good replacement for Freon TF. These solvents are safe, but can be quite
expensive.

Stylus selection is, in the end, at the discretion of the operator and is
made primarily on the basis of sound quality. Appropriately sized truncated
eliptical stlii e.g. D6820TE are a good choice for direct cut discs,
spherical and conical stylii are an option also. Our experience with the
bi-pointed is that they provide better signal to noise straight of the
disc, with no significant increase in distortion. If we were a commercial
organisation I guess this would be a "trade secret" , and my post would
have been of the "send them here and we'll do them for you" variety ;-)

Very good point about the Orthoacoustic EQ standard, which requires 16db
cut at 10kHz and has a 500 Hz low frequency turnover. My main experience
with these has been in the form of limited run pressings for broadcast, but
I guess lacquers cut to this standard would also be very common (perhaps
more so in the US than in Aus). /MD