Serious vinyl quality control problem?
 

On Wed, 4 Feb 2009 19:25:10 +0200, "Iain Churches"
wrote:


"D.M. Procida" wrote in
message
...
I was interested in how heavily modulated vinyl could be, so I popped
an old record (Long Hot Summer Night, Jimi Hendrix, Track Records
1968) under the microscope for a look. And what did I find? Two
adjacent grooves clearly broken into each other:

http://81.174.169.10/odds/grooves.jpg

Was this a really common back then, or is this kind of thing a rarity?

I had a friend with a Bee Gees record. On the first song, there was a
very audible pre-echo of the opening moments (it was something very
loud, "Tragedy" perhaps).

I never really investigated it. I presume it must have been print-though
from a badly stored tape, but I guess it could have been a very
badly-cut record.

Pre-echo can be either - tape or disc. Master tapes were usually
wound and stored tail out to prevent print through caused by storage.
At Decca, we tried to avoid winding by using forward or reverse
play as this gave less winding tension on the reel, and reduced printing.

Iain


Well, there is no excuse for tape print-through at the start of a
track to find its way onto a disc - that bit should be muted. But it
is easy enough to tell which you have by the timing.

d

--
Pearce Consulting
http://www.pearce.uk.com

Serious vinyl quality control problem?
 

"Don Pearce" wrote in message
...
On Wed, 4 Feb 2009 19:17:45 +0200, "Iain Churches"
wrote:


Don Pearce wrote in message news:4992beba.108434515@localhost...
I was interested in how heavily modulated vinyl could be, so I popped
an old record (Long Hot Summer Night, Jimi Hendrix, Track Records
1968) under the microscope for a look. And what did I find? Two
adjacent grooves clearly broken into each other:

http://81.174.169.10/odds/grooves.jpg

Was this a really common back then, or is this kind of thing a rarity?


Neither rare nor common.
It was normal practice to examine heavily modulated passages
under ther microscope after cutting both the test and the final
master. Many cutting engineers used to also test cut loud segments
with excessive lateral excursion several times as a practice run.

But it was impossible to check every single patch with the microscope.
The master was never played, but the initial test cut usually was. If
no problems were encountered with say an SME 3009 and Shure V15
then the master went to the factory.

Are there tracking problems with the Hendrix, Don?

Iain



No, not at all. I was just feeling a bit bored and curious. I thought
that even in '68 there was some automation that predicted amplitude
and widened the pitch a little.


Yes, there was. Most cutting room tape machines had a standard
head bridge with the erase and record heads removed. There was a
"pre-cue" head, about the same distance again upstream, which fed
a servo amp. In addition, manual pitch adjustment was available.

Iain

Serious vinyl quality control problem?
 

On 2/4/2009 9:10 AM Brian Gaff spake thus:

The worst I've encountered is the very audible signal from the adjacent turn
so to speak.
I wonder what your sample had been played on though.

What you're describing has nothing to do with vinyl; you're talking
about "print-through", which is an artifact of the tape mastering
machine feeding the cutter, where you can hear signals from adjacent
lengths of tape.


--
Personally, I like Vista, but I probably won't use it. I like it
because it generates considerable business for me in consulting and
upgrades. As long as there is hardware and software out there that
doesn't work, I stay in business. Incidentally, my company motto is
"If this stuff worked, you wouldn't need me".

- lifted from sci.electronics.repair

Serious vinyl quality control problem?
 

David Nebenzahl wrote:
On 2/4/2009 9:10 AM Brian Gaff spake thus:

The worst I've encountered is the very audible signal from the
adjacent turn so to speak.
I wonder what your sample had been played on though.

What you're describing has nothing to do with vinyl; you're talking
about "print-through", which is an artifact of the tape mastering
machine feeding the cutter, where you can hear signals from adjacent
lengths of tape.

I've heard it a number of times over the years on first play of a vinyl
record, on both 33 and 45 rpm discs, and the pre-echo has always been
*exactly* one revolution ahead of the peak, both on the lead-in and
between tracks or in quiet passages. I'd put it down as an artifact of
either the material of the master deforming slightly while being cut, or
distortion of the plastic while the hot record was cooling after coming
out of the mould. Unless, of course, the feed reel on the tape deck
being used just happened to rotate at the same speed as the turntable.

--
Tciao for Now!

John.

Serious vinyl quality control problem?
 

On 2/4/2009 10:49 AM John Williamson spake thus:

David Nebenzahl wrote:

On 2/4/2009 9:10 AM Brian Gaff spake thus:

The worst I've encountered is the very audible signal from the
adjacent turn so to speak.
I wonder what your sample had been played on though.

What you're describing has nothing to do with vinyl; you're talking
about "print-through", which is an artifact of the tape mastering
machine feeding the cutter, where you can hear signals from adjacent
lengths of tape.

I've heard it a number of times over the years on first play of a vinyl
record, on both 33 and 45 rpm discs, and the pre-echo has always been
*exactly* one revolution ahead of the peak, both on the lead-in and
between tracks or in quiet passages. I'd put it down as an artifact of
either the material of the master deforming slightly while being cut, or
distortion of the plastic while the hot record was cooling after coming
out of the mould. Unless, of course, the feed reel on the tape deck
being used just happened to rotate at the same speed as the turntable.

The latter is much more likely. Can't see how the vinyl could deform
that much and still retain an accurate image from the mold.


--
Personally, I like Vista, but I probably won't use it. I like it
because it generates considerable business for me in consulting and
upgrades. As long as there is hardware and software out there that
doesn't work, I stay in business. Incidentally, my company motto is
"If this stuff worked, you wouldn't need me".

- lifted from sci.electronics.repair

Serious vinyl quality control problem?
 

I was interested in how heavily modulated vinyl could be, so I popped
an old record (Long Hot Summer Night, Jimi Hendrix, Track Records
1968) under the microscope for a look. And what did I find? Two
adjacent grooves clearly broken into each other:

http://81.174.169.10/odds/grooves.jpg

Was this a really common back then, or is this kind of thing a rarity?

Poor quality control from U.S. record suppliers was a large part of
what led me to pretty much stop buying vinyl back in the 1980s.

I became disgusted with the frequent need to return brand-new albums
to the store (often more than once!) in order to get a copy which did
not have objectionable pressing defects.

My impression was that the causes of problems were several-fold:

- Cutting the master with too much modulation (such as the case
you've noticed). This didn't seem to happen too often, but it
did happen sometimes, and was not limited to U.S. pressings (I got
one from Island U.K. which was cut so hot that it was almost
impossible for even a good cartidge to track).

- Poor-quality vinyl stock. This became a really serious issue
during the OPEC oil embargo in the 1970s, as the price of "virgin"
vinyl soared, and most record-makers started using an increasingly
large amount of "regrind" from recycled-and-shredded LPs in their
vinyl mix. I once got a copy of Mike Oldfield's "Hergest Ridge" LP
which had a chunk of paper sticking up out of the groove... they'd
clearly re-ground at least one record into the vat without removing
the entire label area properly :-)

I don't think that the vinyl quality of U.S. mainstream LPs ever
fully recovered after the embargo ended.

- High levels of noise in the groove, which I suspect was due to a
combination of worn stampers and too-fast pressing cycle times
(inadequate time for the hot vinyl to fill the grooves and solidify
properly).

- Scuffs, dirt, and dust from poor handling during manufacture.

I have a feeling that the high cutting levels of some U.S. pressings
may have been in part an attempt to reduce the impact of the noisy
vinyl.

For quite some time, I bought almost all of the music I liked on
imported pressings. European pressing plants, and (especially!)
Japanese ones, were turning out pressings that were quieter and
sounded much better than the U.S. equivalents. It was worth it to me
to pay an extra dollar or three for an import copy of an album I
really wanted, and I dealt with an importer (Greenworld / Paradox in
Torrance, CA) which carried 'em.

Unfortunately, the RIAA and the U.S. labels made a stink about these
"parallel" imports, claiming that the importing of same was an
infringement of the labels' exclusive U.S. license to distribute many
titles. The U.S. government cracked down (I understand that Customs
started seizing shipments), and it became essentially impossible to to
buy an out-of-country pressing of any title which was licensed to a
U.S. label.

I was quite unhappy with the situation and stopped buying music
almost entirely... didn't start again until several years into the CD
era.

--
Dave Platt AE6EO
Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Serious vinyl quality control problem?
 

"David Nebenzahl" wrote in message
s.com...
On 2/4/2009 10:49 AM John Williamson spake thus:


I've heard it a number of times over the years on first play of a vinyl
record, on both 33 and 45 rpm discs, and the pre-echo has always been
*exactly* one revolution ahead of the peak, both on the lead-in and
between tracks or in quiet passages. I'd put it down as an artifact of
either the material of the master deforming slightly while being cut, or
distortion of the plastic while the hot record was cooling after coming
out of the mould. Unless, of course, the feed reel on the tape deck being
used just happened to rotate at the same speed as the turntable.

The latter is much more likely. Can't see how the vinyl could deform that
much and still retain an accurate image from the mold.


I've met that as well, pre-echo exactly one revolution of the disc ahead. It
would seem to be a remarkable co-incidence if all tape spools revolve at
exactly 33 1/3rd rpm! I'm not sure that the fact that you don't understand
the process is important.

David.

Serious vinyl quality control problem?
 

"David Nebenzahl" wrote in message
s.com

I've heard it a number of times over the years on first
play of a vinyl record, on both 33 and 45 rpm discs, and
the pre-echo has always been *exactly* one revolution
ahead of the peak, both on the lead-in and between
tracks or in quiet passages. I'd put it down as an
artifact of either the material of the master deforming
slightly while being cut, or distortion of the plastic
while the hot record was cooling after coming out of the
mould.

The former being the most likely. Remember that when hot plastic is being
deformed to create grooves, it is being supported by the die. When the
lacquer is being cut, the previous groove is not being supported by anything
but air.

Unless, of course, the feed reel on the tape deck
being used just happened to rotate at the same speed as
the turntable.

Unlikely.

The latter is much more likely. Can't see how the vinyl
could deform that much and still retain an accurate image
from the mold.

Heat and pressure backed up by solid metal can really work! ;-)

Serious vinyl quality control problem?
 

Don Pearce wrote in message news:4992beba.108434515@localhost...
I was interested in how heavily modulated vinyl could be, so I popped
an old record (Long Hot Summer Night, Jimi Hendrix, Track Records
1968) under the microscope for a look. And what did I find? Two
adjacent grooves clearly broken into each other:

http://81.174.169.10/odds/grooves.jpg

If you have a scanner, use it to get a good image of the record:
http://www.photosig.com/go/photos/vi...=viewportfolio

Serious vinyl quality control problem?
 

"Arny Krueger" wrote in message
...
"David Nebenzahl" wrote in message
s.com

I've heard it a number of times over the years on first
play of a vinyl record, on both 33 and 45 rpm discs, and
the pre-echo has always been *exactly* one revolution
ahead of the peak, both on the lead-in and between
tracks or in quiet passages. I'd put it down as an
artifact of either the material of the master deforming
slightly while being cut, or distortion of the plastic
while the hot record was cooling after coming out of the
mould.

The former being the most likely. Remember that when hot plastic is being
deformed to create grooves, it is being supported by the die. When the
lacquer is being cut, the previous groove is not being supported by
anything but air.

Exactly. And in addition the lacquer surface is softened
to some extent by the physical heating of the cutter stylus
for a quieter cut.

Iain