In article
,
D.M. Procida wrote:
RJH wrote:

Well, it won't do that without some force. Something is pushing it
back. Maybe it is not as free as you think. Alternatively, look at
Jim's suggestion that the bias is set wrongly. I don't know how it
is applied on this arm, but if you adjust it off as far as possible,
that will tell you if it is responsible.

d


Sounds like a combination of wildly out tracking weight, bias
adjustment and turntable level. Can't think how/why else that could
happen. Has the TT been moved or adjusted recently?

I had a new cartridge fitted a while ago by a local hifi shop.

On further checking, the tracking weight is too low.

In fact it can't be set higher than 1.6g (for a Goldring Elan cartridge)
because the cartridge has been mounted right at the close end of the
mount, rather than in the middle.

If the overhang is wrong the skating force may be out, and could cause
problems consistent with your report.

Do you have an alignment protractor and a test LP? FWIW I tend to recommend
the Analogue Productions "Ultimate Test LP". I did some comparisons of test
LPs a few years ago and concluded this was better made than many others. If
you don't have one, I think you can get something like a PDF on the web
somewhere of a protractor to print and stick to a card.

If they'd put it in a more sensible place there'd be a proper range of
adjustment.

I'll try it on 1.6g and see what happens, but I am not very impressed by
the way it was installed.

Again, if you alter the downforce you should try a test LP as it will show
up any mistracking or marked rise in distortion if you haven't got the
right 'trade off' for the various factors involved.

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

Jim Lesurf wrote:

In fact it can't be set higher than 1.6g (for a Goldring Elan cartridge)
because the cartridge has been mounted right at the close end of the
mount, rather than in the middle.

If the overhang is wrong the skating force may be out, and could cause
problems consistent with your report.

Do you have an alignment protractor and a test LP? FWIW I tend to recommend
the Analogue Productions "Ultimate Test LP". I did some comparisons of test
LPs a few years ago and concluded this was better made than many others. If
you don't have one, I think you can get something like a PDF on the web
somewhere of a protractor to print and stick to a card.

I'll give that a try.

Thanks for the advice,

Daniele

On 14/12/2012 14:16, Jim Lesurf wrote:
In article , Bob Latham
wrote:
In article , Jim Lesurf
wrote:

My only personal experience with the Linn was ye olde Ittok/Asak.
Which I found a total PITA. Massive end-of-side distortion even when
aligned as well as possible. It always puzzled me that people seemed
not to notice this.

I've never noticed it at all.

It depends on the type of music played. It seemed very obvious to me on
orchestral climaxes with massed strings, etc, at an end-of-side. But may
well not be noticed on others things like rock music with electric guitars
and drums. It may also hinge a bit on how familiar the listener is with
live music inc things like massed strings, etc. And FWIW my impression
was that the mistracking could give more 'impact' to rock music, so
a result that I guess some people would like, depending on taste in
music, etc.


I found it very cartridge dependent. For example, I simply couldn't get
a Goldring (1040 ISTR, and not cheap) cartridge to track properly at all
on inner tracks, with distortion on vocals and strings.

I've had this experience with several other cartridges, and leaving
installation error aside (it's one of the few things I can get right!),
I found it baffling that the issue wasn't widely reported. Sample
variation? who knows.

The solution for me was/is the AT OC series. I imported a couple from
the US - about 1/4 of UK retail after tax and handling.

Back to the OP - I think this phenomenon is too subtle to explain what's
happening though.

Rob

In article om, RJH
wrote:
On 14/12/2012 14:16, Jim Lesurf wrote:
In article , Bob Latham
wrote:
In article , Jim Lesurf
wrote:

My only personal experience with the Linn was ye olde Ittok/Asak.
Which I found a total PITA. Massive end-of-side distortion even when
aligned as well as possible. It always puzzled me that people seemed
not to notice this.

I've never noticed it at all.

It depends on the type of music played. It seemed very obvious to me
on orchestral climaxes with massed strings, etc, at an end-of-side.
But may well not be noticed on others things like rock music with
electric guitars and drums. It may also hinge a bit on how familiar
the listener is with live music inc things like massed strings, etc.
And FWIW my impression was that the mistracking could give more
'impact' to rock music, so a result that I guess some people would
like, depending on taste in music, etc.


I found it very cartridge dependent. For example, I simply couldn't get
a Goldring (1040 ISTR, and not cheap) cartridge to track properly at all
on inner tracks, with distortion on vocals and strings.

My comments (above) were really directed at the Asak, having had to use one
for some time before/during a show ages ago. I've *assumed* the Ittok
wasn't really a main factor. But for all I know, it was. However the
experience just encouraged my move towards a direct-drive and a Shure.
Happy with that to date. :-)

More generally, poor tracking can arise for various reasons, due to
cartridge, or arm, or some detail of setup not being correct. Lots of
variables to get 'not quite right', alas.

I've had this experience with several other cartridges, and leaving
installation error aside (it's one of the few things I can get right!),
I found it baffling that the issue wasn't widely reported. Sample
variation? who knows.

The solution for me was/is the AT OC series. I imported a couple from
the US - about 1/4 of UK retail after tax and handling.

Back to the OP - I think this phenomenon is too subtle to explain what's
happening though.

Rob

In general, something I noticed over the years was that MC carts often
tended to have a far higher tip mass, and much lower compliance than
something like ye olde Shure MMs. That does mean more force is needed to
push the stylus modulation. I suspect that also means it becomes easier for
something like a setup problem or arm pivot friction to tip pun alert!
the mistracking up to high levels, or cause the stylus to leap out of the
groove in extreme cases. The difficulty, though, is trying to diagnose the
specifics in cases which you can't check though and measure or experiment
with. So we can only guess the reasons for the OPs problem and suggest
plausible candidates for investigation.

When I did compare some 'modern' cartridges a few years ago I did like the
Orthophon 'M2 Black'. But my feeling was that even this had a much higher
tip mass and low compliance than an old Shure. However it worked well. I do
regard AT as a good maker, but I haven't tested or used any of their
cartridges in decades. So as things stand if I wanted a new cartridge it
would be the M2 Black, I guess. It is annoying that some items (like the AT
OC) are 'difficult to get' in the UK. Much the same problem as afflicts
things like SACDs or high res downloads. Given the touted 'globalised
market' it is curious that individuals may have to go out of their way to
get such items from Japan or the USA. Sometimes in the face of restrictions
on purchase.

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

On Fri, 14 Dec 2012 13:54:30 +0000,
(D.M. Procida) wrote:

RJH wrote:

Well, it won't do that without some force. Something is pushing it
back. Maybe it is not as free as you think. Alternatively, look at
Jim's suggestion that the bias is set wrongly. I don't know how it is
applied on this arm, but if you adjust it off as far as possible, that
will tell you if it is responsible.

d


Sounds like a combination of wildly out tracking weight, bias adjustment
and turntable level. Can't think how/why else that could happen. Has the
TT been moved or adjusted recently?

I had a new cartridge fitted a while ago by a local hifi shop.

On further checking, the tracking weight is too low.

In fact it can't be set higher than 1.6g (for a Goldring Elan cartridge)
because the cartridge has been mounted right at the close end of the
mount, rather than in the middle.

If they'd put it in a more sensible place there'd be a proper range of
adjustment.

I'll try it on 1.6g and see what happens, but I am not very impressed by
the way it was installed.


It seems to me that it may be something wedged around the tone arm
pivot (you mentioned a cartridge change in your later posting). If you
can, take a closer look at the cartridge lead wires where they exit
the tone arm and verify whether or not they are misrouted in such a
fashion as to create the effect of springy 'end stop'.

Regarding cartridge tracking downforce, it's usually best to choose
the upper end of the recommended range, rather than the lower end. A
1.4 gramme downforce equates to a 1 gramme groove wall force which,
with an effective tip mass of 1mg (typical for most quality
cartridges) yields a maximum acceleration of 1,000G. Loud passages on
some heavily modulated pressings can easilly exceed the 1,000G mark.

Insufficient down force will create mistracking distortion (where the
stylus stops following the groove wall modulation (the HiFi equivilent
to the issue of weak valve springs on a high revving souped up car
engine where this produces valve bounce).

In this case, the groove wall modulation falls away from the stylus
tip faster than the downforce can accelerate it, resulting in it
parting company only to smash into the groove wall when the modulation
starts to (or has started to) reverse direction.

A record played sufficiently often on such a setup will eventually
suffer groove wall damage emulating the original tracking distortion
when the condition is either corrected or it is played on a better and
properly setup turntable. IOW, insufficient downforce does more harm
than a modest excess of downforce ever will.

Regarding the issue of sideforce bias compensation, the word
"anti-skating" should never grace any discussion involving record
decks and tone arm setup. The correcting bias can only be an
approximation to counter an effect directly attributable to the
overhang required on a single pivot arm to minimise angular
displacement from the ideal 90 deg wrt the tangent at the point of
contact.

There was a period (mercifully brief, afaicr) where you could buy a
blank grooveless record to calibrate your "anti-skate" compensation.
The (bogus) idea being that you could immediately see the effect of
the adjustments as a veering away from the halfway point either
inwards or outwards. Sadly, the condition that pertained with a blank
grooveless disk was so radically different to 'real life' that any
such adjustments became totally inappropriate when playing an actual
vynil disk recording.

The best way (apart from using the tone arm or cartridge
manufacturer's guidelines) was to use a test record with a range of
fixed frequency tones specially chosen for the task at varying levels
and points along the groove where you could carefully audition for
mis-tracking distortion or (for those more technically dedicated) use
a distortion meter or oscilloscope.

When I was doing this, some 30 odd years ago, I was staggered by how
much of the highest level of 300Hz test tone energy was reaching the
pivot of the SME3009 (detected by the vibration that could be detected
by a finger tip pressed to the junction of the arm's pivot bearing
mounting and the baseboard.

The SME was mounted to the baseboard using rubber vibration damping
gromets - those gromets were quite obviously having a (hopefully)
beneficial effect in reducing the risk of pivot bearing chatter adding
to the mistracking distortion levels.

Some manufacturers (B & O being one that comes readily to mind) did
try to eliminate this issue by using a servo tracked arm hanging off a
slide bar and lead screw assembly running parallel to 90 degrees wrt
the tangent of contact of the stylus tip with the groove. It certainly
solved the sidethrust issue but introduced other issues (which,
afaicr, may have been more significant that those in the traditional
arrangement - quite possibly the idea was simply dropped due to the
relatively high cost and added complexity for a marginal improvement).

--
Regards, J B Good

Johny B Good wrote:

I'll try it on 1.6g and see what happens, but I am not very impressed by
the way it was installed.


It seems to me that it may be something wedged around the tone arm
pivot (you mentioned a cartridge change in your later posting). If you
can, take a closer look at the cartridge lead wires where they exit
the tone arm and verify whether or not they are misrouted in such a
fashion as to create the effect of springy 'end stop'.

No, there was no springiness at the end, but the arm wasn't adequately
weighted, and probably the bias was set incorrectly.

Some manufacturers (B & O being one that comes readily to mind) did
try to eliminate this issue by using a servo tracked arm hanging off a
slide bar and lead screw assembly running parallel to 90 degrees wrt
the tangent of contact of the stylus tip with the groove. It certainly
solved the sidethrust issue but introduced other issues (which,
afaicr, may have been more significant that those in the traditional
arrangement - quite possibly the idea was simply dropped due to the
relatively high cost and added complexity for a marginal improvement).

I knew someone in the 1980s who, for his Sixth Form electronics project,
designed and built a parallel tracking tonearm using parts from a model
train set.

There is one thing I don't understand about bias though.

It seems to me that since the spiral groove moves the needle inwards, it
must be the face of the grove that's towards the outer edge of the
record that's exerting a force on it.

In other words, if the groove were a wide U-shaped-channel rather than a
V, the needle would be pushed inwards by the wall of the channel on the
outside.

So I'd expect there to be higher pressure from the needle on that face
of the channel.

Yet bias adjustments exert a force moving the tonearm outwards, in the
opposite direction, which seems to me will further increase the pressure
on that wall, whereas to eliminate it, the bias should encourage the arm
to swing towards the centre.

Daniele

On Sat, 15 Dec 2012 20:11:03 +0000,
(D.M. Procida) wrote:

Johny B Good wrote:

I'll try it on 1.6g and see what happens, but I am not very impressed by
the way it was installed.


It seems to me that it may be something wedged around the tone arm
pivot (you mentioned a cartridge change in your later posting). If you
can, take a closer look at the cartridge lead wires where they exit
the tone arm and verify whether or not they are misrouted in such a
fashion as to create the effect of springy 'end stop'.

No, there was no springiness at the end, but the arm wasn't adequately
weighted, and probably the bias was set incorrectly.

Some manufacturers (B & O being one that comes readily to mind) did
try to eliminate this issue by using a servo tracked arm hanging off a
slide bar and lead screw assembly running parallel to 90 degrees wrt
the tangent of contact of the stylus tip with the groove. It certainly
solved the sidethrust issue but introduced other issues (which,
afaicr, may have been more significant that those in the traditional
arrangement - quite possibly the idea was simply dropped due to the
relatively high cost and added complexity for a marginal improvement).

I knew someone in the 1980s who, for his Sixth Form electronics project,
designed and built a parallel tracking tonearm using parts from a model
train set.

There is one thing I don't understand about bias though.

It seems to me that since the spiral groove moves the needle inwards, it
must be the face of the grove that's towards the outer edge of the
record that's exerting a force on it.

In other words, if the groove were a wide U-shaped-channel rather than a
V, the needle would be pushed inwards by the wall of the channel on the
outside.

So I'd expect there to be higher pressure from the needle on that face
of the channel.

Yet bias adjustments exert a force moving the tonearm outwards, in the
opposite direction, which seems to me will further increase the pressure
on that wall, whereas to eliminate it, the bias should encourage the arm
to swing towards the centre.


You need to examine what's going on quite closely to figure out
what's actually happening in this case. The classic tone arm provides
overhang and offset (angle wrt a line joining the stylus tip and the
pivot bearing).

The 'benefit' being achieved here is a reduction in the angular
variation error that the stylus cantilever suffers wrt to the ideal of
tangential alignment with the groove.

Without the offset and overhang, this happy state of affairs will
only exist at one point during playback with serious departures at the
start and end if adjusted for perfect alignment to happen in the
middle (unless you care to use a 3 foot or longer tone arm to reduce
this error - an impractical solution).

The overhang and offset considerably reduces the angular errors by
lining up perfectly at two (or was it three?) points along its
traverse but there is a price to pay.

Since the drag from the stylus is pretty closely aligned to the
offset angle the drag force is trying to pull the stylus towards the
spindle and is only restrained from doing so by the resultant increase
of force on the inner groove wall. The best analogy I can think of is
that of keeping a horse drawn barge away from the bank the towpath is
on by judicious use of the tiller to compensate the shorward component
in the towing force vector provided by the horse.

If no measures are taken to compensate this drag induced side thrust,
the trackability on the outer wall will be noticably less than on the
inner wall which, at the louder parts of the recording, cause the
onset of tracking distortion to manifest itself prematurely on one
channel whilst the other is still coping quite nicely and with
something to spare.

The side bias is designed to reduce this overhang/offset induced
unbalance of tracking pressure between the stylus tip and the two
walls of the groove. There's no point in having just one channel of a
stereo pair being able to cope with the louder passages if the other
channel has already started to exhibit gross tracking distortion. The
side bias only mitigates the worst effects of this imbalance since it
can't exactly cancel all the variables involved.
--
Regards, J B Good

In article , Johny B Good
wrote:
On Fri, 14 Dec 2012 13:54:30 +0000,
(D.M. Procida) wrote:

RJH wrote:


It seems to me that it may be something wedged around the tone arm
pivot (you mentioned a cartridge change in your later posting). If you
can, take a closer look at the cartridge lead wires where they exit the
tone arm and verify whether or not they are misrouted in such a fashion
as to create the effect of springy 'end stop'.

Yes, that is quite a plausible cause of a rise in sideways force.

Regarding cartridge tracking downforce, it's usually best to choose the
upper end of the recommended range, rather than the lower end. A 1.4
gramme downforce equates to a 1 gramme groove wall force which, with an
effective tip mass of 1mg (typical for most quality cartridges) yields a
maximum acceleration of 1,000G. Loud passages on some heavily modulated
pressings can easilly exceed the 1,000G mark.

[snip]

Regarding the issue of sideforce bias compensation, the word
"anti-skating" should never grace any discussion involving record decks
and tone arm setup.

Erm... if you wish to be picky about that, you may also need to be so about
calling "grammes" as "tracking downforce". :-)


There was a period (mercifully brief, afaicr) where you could buy a
blank grooveless record to calibrate your "anti-skate" compensation. The
(bogus) idea being that you could immediately see the effect of the
adjustments as a veering away from the halfway point either inwards or
outwards. Sadly, the condition that pertained with a blank grooveless
disk was so radically different to 'real life' that any such adjustments
became totally inappropriate when playing an actual vynil disk recording.

The best way (apart from using the tone arm or cartridge manufacturer's
guidelines) was to use a test record with a range of fixed frequency
tones specially chosen for the task at varying levels and points along
the groove where you could carefully audition for mis-tracking
distortion or (for those more technically dedicated) use a distortion
meter or oscilloscope.

Again, I'd agree with that! The old 'blank disc' approach for this is
likely to be useless.

When I was doing this, some 30 odd years ago, I was staggered by how
much of the highest level of 300Hz test tone energy was reaching the
pivot of the SME3009 (detected by the vibration that could be detected
by a finger tip pressed to the junction of the arm's pivot bearing
mounting and the baseboard.

I have long felt that the growth in anxiety about 'tone arm resonances'
stemmed from the MC carts that grew popular having much lower compliance
and tip mass than the Shure/Empire/etc MMs. Thus injecting much higher
vibrational force into the arm.

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

In article
,
D.M. Procida wrote:
Johny B Good wrote:


There is one thing I don't understand about bias though.

It seems to me that since the spiral groove moves the needle inwards, it
must be the face of the grove that's towards the outer edge of the
record that's exerting a force on it.

In other words, if the groove were a wide U-shaped-channel rather than a
V, the needle would be pushed inwards by the wall of the channel on the
outside.

So I'd expect there to be higher pressure from the needle on that face
of the channel.

Yet bias adjustments exert a force moving the tonearm outwards, in the
opposite direction, which seems to me will further increase the pressure
on that wall, whereas to eliminate it, the bias should encourage the arm
to swing towards the centre.

As JBG has explained in detail. The (unwanted) radial force comes from the
geometry of the way the arm holds the stylus wrt the record. This is why I
referred to 'overhang'. The stylus is located at a point that is further
from the pivot than the place along the arm that is perpendicular to a
radial line. i.e. overhung. And angled.

The rotating groove 'drags' the stylus. Some of this force tries to pull
the arm. But the drag is inclined inward at an angle to the arm. So it also
tries to rotate the arm and move the stylus inward, radially. In the
absence of any other correcting forces being applied this (normally) means
the stylus pushes against the 'inner' wall (i.e. the one closer to the
center of the LP) than the 'outer' wall. So an "anti skating" or "bias"
force is added to try and counter this effect by trying to pull the arm
outward by a balancing amount.

This isn't just a matter of keeping the sylus in the groove. It also
affects the level of distortion and mistracking of louder sounds. So has an
audible effect on the music.

IIRC the 'bias' idea was actually devised by John Crabbe (editor for many
years of HFN) who (I think) came up with the 'thread and weight' method.

The problem is that the actual drag varies. Depends on the details of the
LP and the stylus. So varies as you play a normal LP, and from one LP to
another. Hence any adjustments made using a test LP tend to be just getting
you into the right kind of setup. Better than not bothering, but not a
complete solution.

Slainte,

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

Johny B Good wrote:

Since the drag from the stylus is pretty closely aligned to the
offset angle the drag force is trying to pull the stylus towards the
spindle and is only restrained from doing so by the resultant increase
of force on the inner groove wall. The best analogy I can think of is
that of keeping a horse drawn barge away from the bank the towpath is
on by judicious use of the tiller to compensate the shorward component
in the towing force vector provided by the horse.

I'm still struggling with all this.

Still:

* the horse (tonearm pivot) stands firmly stationary by the side of the
canal

* the horse is connected to the barge (stylus) not with a rope, but a
rigid bar, that means horse and barge must always face the same
direction

* the rapidly-flowing canal (the vinyl groove) tugs at the barge as it
goes by

* because the horse is offset from the direction of the water's tug, the
whole assembly of horse, bar and barge wants to rotate around the horse,
towards the bank

I think I understand that, but it must be more complicated.

For example, when the needle is in the middle of the side (assuming
that's where the tonearm is parallel to the tangent of the groove) that
would be like having the horse directly upstream of the barge, not to
one side.

And, either side of that middle, the force on the tonearm must always be
towards the middle of the side, suggesting you'd need positive bias
adjustment for the first half and negative bias for the second.

Daniele