Arny Krueger wrote:
"Arny Krueger" wrote in message

"Don Pearce" wrote in message
et
Arny Krueger wrote:

http://delback.co.uk/turntable_tests/
For grins, you might try to extract some frequency
response information from them.
The Linn Sondek in that last link has the most fearsome
wow (about 0.3% RMS) - bad enough to be a real fault, I
think.

Correct that. The predominate jitter frequency seems to be 0.55 Hz -
off-center record.



A test record shouldn't be able to go off-centre. All of mine are
drilled small, and are a very tight fit on the spindle.

d

"Don Pearce" wrote in message
et
Arny Krueger wrote:
"Arny Krueger" wrote in message

"Don Pearce" wrote in message
et
Arny Krueger wrote:

http://delback.co.uk/turntable_tests/
For grins, you might try to extract some frequency
response information from them.

The Linn Sondek in that last link has the most fearsome
wow (about 0.3% RMS) - bad enough to be a real fault, I
think.

Correct that. The predominate jitter frequency seems to
be 0.55 Hz - off-center record.

A test record shouldn't be able to go off-centre. All of
mine are drilled small, and are a very tight fit on the
spindle.

Who says that the hole was necessarily drilled or punched in the right
place?

Where else do we get 0.55 Hz FM from?

"Arny Krueger"

A test record shouldn't be able to go off-centre. All of
mine are drilled small, and are a very tight fit on the
spindle.

Who says that the hole was necessarily drilled or punched in the right
place?

Where else do we get 0.55 Hz FM from?


** A defective belt will do that to a 33.3 rpm table.



...... Phil

On Wed, 19 Nov 2008 18:11:02 -0500, "Arny Krueger"
wrote:

"Don Pearce" wrote in message
net
Arny Krueger wrote:
"Arny Krueger" wrote in message

"Don Pearce" wrote in message
et
Arny Krueger wrote:

http://delback.co.uk/turntable_tests/
For grins, you might try to extract some frequency
response information from them.

The Linn Sondek in that last link has the most fearsome
wow (about 0.3% RMS) - bad enough to be a real fault, I
think.

Correct that. The predominate jitter frequency seems to
be 0.55 Hz - off-center record.

A test record shouldn't be able to go off-centre. All of
mine are drilled small, and are a very tight fit on the
spindle.

Who says that the hole was necessarily drilled or punched in the right
place?

Where else do we get 0.55 Hz FM from?


There are some bad test records to be had. I measured some files from
two high-end turntables for an ex. Brit. 'friend' of yours. Both
showed almost the same bad results... then another test record was
used and then they showed different (not too good) results. My lips
are sealed..

On Wed, 19 Nov 2008 18:11:02 -0500, "Arny Krueger"
wrote:

"Don Pearce" wrote in message
net
Arny Krueger wrote:
"Arny Krueger" wrote in message

"Don Pearce" wrote in message
et
Arny Krueger wrote:

http://delback.co.uk/turntable_tests/
For grins, you might try to extract some frequency
response information from them.

The Linn Sondek in that last link has the most fearsome
wow (about 0.3% RMS) - bad enough to be a real fault, I
think.

Correct that. The predominate jitter frequency seems to
be 0.55 Hz - off-center record.

A test record shouldn't be able to go off-centre. All of
mine are drilled small, and are a very tight fit on the
spindle.

Who says that the hole was necessarily drilled or punched in the right
place?

Where else do we get 0.55 Hz FM from?


Well, that's the wow. The raison d'etre of a test record is that it is
in itself far better than what you are testing. If we can't trust the
makers even to put the hole in the middle we may as well all give up
right now.

d

"Jim Lesurf" wrote in message
...
Just posting to let people know that audiomisc.co.uk now includes a web
version of the 4th article in my recent HFN series on LP. This one
provides
measured results for the old Shure V15/III and compares it with some
modern
MM carts. Also has some close up photos of each stylus, etc.


Excellent article, Jim.

It confirms why even now the Shure V15III is so often
the cartridge of choice for many discerning transcription
clients.

Iain

"Phil Allison" wrote in message
...

"Arny Krueger"

A test record shouldn't be able to go off-centre. All of
mine are drilled small, and are a very tight fit on the
spindle.

Who says that the hole was necessarily drilled or punched in the right
place?

Where else do we get 0.55 Hz FM from?


** A defective belt will do that to a 33.3 rpm table.

Wouldn't the length of the belt have to be a multiple of the circumference
of the sub-platter (or whatever the belt goes around) for that to be a
cause?

"Grumps" wrote in message

"Phil Allison" wrote in message
...

"Arny Krueger"

A test record shouldn't be able to go off-centre. All
of mine are drilled small, and are a very tight fit on
the spindle.

Who says that the hole was necessarily drilled or
punched in the right place?

Where else do we get 0.55 Hz FM from?

** A defective belt will do that to a 33.3 rpm table.

Wouldn't the length of the belt have to be a multiple of
the circumference of the sub-platter (or whatever the
belt goes around) for that to be a cause?

IOW, a defective belt with dimensional issues is going to cause speed
variations that have a period that is based on its length divided by its
linear speed. The belt has to be appreciably longer than the diameter of the
driven member, so the period of its longest-term periodic contribution must
be lower than 0.55 Hz.

A belt could be defective, harden up and be so stiff that it did not provide
the desired low-pass filter action.

Also, a belt might get so hard that it slips, which may or may not create
variations that are based on the length of the belt.

Don Pearce wrote in message
news:49252ae2.230285046@localhost
On Wed, 19 Nov 2008 18:11:02 -0500, "Arny Krueger"
wrote:

"Don Pearce" wrote in message
et
Arny Krueger wrote:
"Arny Krueger" wrote in message

"Don Pearce" wrote in message
et
Arny Krueger wrote:

http://delback.co.uk/turntable_tests/
For grins, you might try to extract some frequency
response information from them.

The Linn Sondek in that last link has the most
fearsome wow (about 0.3% RMS) - bad enough to be a
real fault, I think.

Correct that. The predominate jitter frequency seems to
be 0.55 Hz - off-center record.

A test record shouldn't be able to go off-centre. All of
mine are drilled small, and are a very tight fit on the
spindle.

Who says that the hole was necessarily drilled or
punched in the right place?

Where else do we get 0.55 Hz FM from?

Well, that's the wow.

Agreed.

The raison d'etre of a test record
is that it is in itself far better than what you are
testing.

Some people seem to be a little weak on that point. ;-)

If we can't trust the makers even to put the
hole in the middle we may as well all give up right now.

Well, that's the problem with the LP format. It's dependent on all these
little mechanical thingies that even the people who are making short runs of
$50 test records can't seem to get right. What hope would there be for the
$2.95 LPs that you bought at the K-Mart store in the day of?

Well, us older folks know the answer to that - not much hope for the LP. 99%
of all music lovers moved on past the LP for this and many other related
reasons.

However, if you think that music with built-in wow is somehow "more musical"
than music with no audible flutter and wow, then that would be a pretty
strange view on "High Fidelity". To be exact, it would be "Low Fidelity".

"Iain Churches" wrote in message
.fi
"Jim Lesurf" wrote in message
...
Just posting to let people know that audiomisc.co.uk now
includes a web version of the 4th article in my recent
HFN series on LP. This one provides
measured results for the old Shure V15/III and compares
it with some modern
MM carts. Also has some close up photos of each stylus,
etc.

Excellent article, Jim.

It confirms why even now the Shure V15III is so often
the cartridge of choice for many discerning transcription
clients.

It also shows that at its best, the LP format falls way behind most other
parts of a high quality reproduction chain. Furthermore, the LP was usually
appreciably worse than the best it could be, as the two other cartridges
show.

We've got other examples of people with impressive-sounding kit that had
frequency variations on the order of 10 dB within the 50-15 kHz range.