Re: [ARSCLIST] ET groove cutting ( was "More about ET preservation", was "Comparable collections anywhere?")

["Scott D. Smith" <lists@xxxxxxxxxxxxxxxx>]

Eric,

All very good questions! I'm sure Graham will jump in here with some 
well-informed answers as well, which I would love to hear about. While I 
have never cut 16" transcriptions, here's what I can tell you from my 
experience cutting LP's and 45 RPM discs back in the day:

1. The condition of the cutting styli does indeed play a big role in the 
quality of the groove. This is especially the case if the is any debris 
stuck to the cutting edge of the styli (which was not uncommon). Some 
styli were slighty better polished than others as well.

2. The geometry of the styli also plays a big role. It was my experience 
that some styli could cause a slight "chatter" or squeal during cutting 
on some acetate blanks. This would subsequently manifest itself in the 
groove wall, where you could hear a very slight "squeal" on 
reproduction, depending on what part of the groove wall the playback 
stylus rode on (with the upper part of the wall usually being the 
problem area). The alignment of the styli and the cutting head 
temperature also were a big factor in this. It was my experience that 
slight changes in the acetate formulation of the blanks were also a 
factor (even from the same manufacturer).

3. The proper setting of the proper groove depth was also very critical, 
as too deep a cut could cause problems with the "chip" not being 
properly shed off from the edge of the styli, which was also the major 
factor that could cause the slight "squeal" alluded to above.

All in all, not a task for the faint-of-heart, even with a modern 
Neumann VMS lathe with computurized control and a preview head. While it 
was interesting, I'm glad to not have to deal with it any longer on a 
regular basis. One bad acetate, a problem with the chip running afoul of 
the styli, an amplifier noise, etc. and an hour of your time is wasted 
in a flash. If you weren't lucky enough to have a computerized lathe, 
your chances of ending up with a bad master were increased by a huge 
factor.

Of course, if you had everything working in your favor, an all the 
planets were aligned right, the resulting quality could at times be 
quite stunning. More often than not, however, the poor QC on commercial 
pressings pretty much guaranteed a mediocre finished product. Maybe the 
guy in plating went on a bender the night before, maybe the hole gets 
punched slightly off-center, the acetate gets damaged on the way to the 
plant, the list goes on. (I am, of course, not including audiophile 
discs done by Sheffield, Mobile Fidelity and others,which showed off 
what the medium was truly capable of).

Graham may have fonder memories.....me, I'm happy to see 'em go.

Scott D. Smith



Eric Jacobs wrote:

> Hi Graham,
>
> Thanks so much for the kind words.
>
> I stare at ET grooves all day it seems through a microscope, and I've
> noticed that some of the groove bottoms are sometimes not as smooth as
> others - there will be parallel striations, or in some cases the walls
> look smooth but the bottom is very rough, almost jagged.  At first I
> thought perhaps this was groove wear, but the more I think about it and
> see actual groove wear, I now think it's a poorly cut groove, like the
> cutter wasn't hot enough or was cutting too deep or was perhaps dull or
> mis-shapen or at the wrong angle...  I can look at and measure a groove
> now and pretty much know in advance how much noise I can expect from
> each stylus.  It would be nice to better understand WHY the grooves look
> the way they do.
>
> Since you've actually cut discs (wow, that is SO cool), can you shed
> some insight into what phenomenon I might be seeing?  I'd like to be
> able to classify groove condition more accurately in the technical
> metadata, including poorly cut grooves (if that is indeed the case).
>
> Eric Jacobs
> Principal
>
> The Audio Archive
> tel: 408.221.2128
> fax: 408.549.9867
> mailto:EricJ@xxxxxxxxxxxxxxxxxxx
>
>
> -----Original Message-----
> From: Graham Newton [mailto:gn@xxxxxxxxxxxxxxxxxxxxx]
> Sent: Wednesday, September 13, 2006 6:13 AM
> To: ARSCLIST@xxxxxxxxxxxx
> Cc: ericj@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [ARSCLIST] More about ET preservation (was "Comparable
> collections anywhere?")
>
>
> Eric Jacobs wrote:
>
>  
>
> > There are three things that affect the condition of ETs:
> >    
> <HUGE snip!>
>
> Eric has written a very good outline of the problems and considerations
> needed
> when handling and transferring lacquer coated discs in general and of any
> size,
> not just "ET's" (Electrical Transcriptions).
>
> For those of us who lived the era of their use, most of the problems were
> obvious, but none of us expected the deterioration and decomposition that is
> being encountered today.
>
> I actually cut 16" lacquers, as well as thousands of LP masters while I
> worked
> for RCA Victor in the early 1960's... a long time ago in a galaxy far, far
> away, and yes, it was a great adventure!
>
>
>
>
> ... Graham Newton
>
> --
> Audio Restoration by Graham Newton, http://www.audio-restoration.com
> World class professional services applied to tape or phonograph records for
> consumers and re-releases, featuring CEDAR's new CAMBRIDGE processes.
>
>
>
>