What is your approach to Anti-skating?

[Thermionic Idler]

I'd like to submit a question to the collective if I may.

Most of you presumably will have an arm equipped with bias compensation a.k.a. anti-skate. What was your approach for setting it? I.E. do you not use it at all, did you do it by ear, or by use of a test LP, or the most common method of placing the needle on an unmodulated record surface and adjusting until it remained static?

Also has anyone experienced long term cartridge wear issues which could be attributed to too high/low an anti-skate setting? Is anti-skating less critical on a 12" arm?

I know this might seem odd coming from someone running an arm with no anti-skate facility but there is method in my madness!

[chelsea]

Just use un grooved part of test record,and get it stationary.

[Rare Bird]

For a start i hate sprung Anti-Skate dial.. String weight or nowt..

I work within the Manufacturers recommendation, when im happy i then move onto the blank record (no groove) see if it drifts 2/3rds down the disc..i don't set it by that it's just peace of mind to see it not drifting..

[UV101]

For a start i hate sprung Anti-Skate dial..


But what if thats all you have????

[Audioman]

Set to a little less than the playing weight and use ears to adjust up or down.

[steveledzep]

But what if thats all you have????

That's all I have on a Roksan Tabriz Zi. Fortunately, a gentle hand can set it on the fly. My MC25FL is tracking at 2.1 grammes but my anti-skate has been set by ear to 0.6 grammes. Set at 2.1 g, there is a channel imbalance, I adjust until it sounds "right" to me. My cdp tells me there isn't a channel imbalance attributable to amp or speakers etc. so I am happy.

[OneyedK]

My MC25FL is tracking at 2.1 grammes but my anti-skate has been set by ear to 0.6 grammes. Set at 2.1 g, there is a channel imbalance, I adjust until it sounds "right" to me.
Are you sure your azimuth is set correctly?
If your stylus "stands" less than perfect in the groove, this would be one of the symptoms...

[DSJR]

Each arm is different around a sort of nominal average setting, each cartridge/stylus has different requirements and so the whole thing has to be fine tuned individually. I tend to use a blank piece of vinyl to get the basic setting and tune it from there, depending on the cartridge sample.

[AlanS]

You have missed a valid option.

My approach is very chilled.

I use Anti Skate but none of the above!
Just set the dial to same as tracking why get into a lather about it?

[RobbieGong]

Yep agreed re: above post ! - Widely and most commonly recommended by turntable manufacturers to set anti skate to same as / within same range as tracking force weight, afterwhich really not worth losing sleep over. Included alongside usual azimuth / vta and protrator tonearm set up process, I've never had a problem.

[Beobloke]

If speed is of the essence I generally go for half to three quarters of the tracking weight value.

When I'm doing it properly I break out the test LP and oscilloscope and set for equal distortion in each channel.

[chelsea]

I have a weight pulley type on my arm.
It needs 4.5g anti skate and 1.9 for cart weight.

[AlanS]

I know this might seem odd coming from someone running an arm with no anti-skate facility but there is method in my madness!

When will you reveal?

[OneyedK]

Just set the dial to same as tracking why get into a lather about it?
Skating itself does depend on the shape of the stylus and the quality/polish of the diamond.
It can vary quite a bit from the VTF setting...

But it's everybodys right not to care...

[mike1210]

I use a blank record and adjust until the needle stops moving.

[steveledzep]

Are you sure your azimuth is set correctly?

Thanks for that, good point. Azimuth is as good as I can set it by eye using a flat mirror. :)

[The Grand Wazoo]

I was once told by a certain dealer (who used a turntable in his own system) not to bother with anti-skating as it always sounds better with none applied.
I never bought anything from him!

[stewartwen]

As Adam has said I use a scope and a test record. This is so the stylus sits in the centre of the groove. Although fine line stylii require very painstaking set up procedures, in the days when conical stlyii were very popular bias was not deemed as critical, but if the tracking weight was lighter than the mfrs recommended minimum all sorts of problems arose.
It is essential to use a set up procedure that uses a template which has been designed for the offset angle of the pick up arm!
If you are using a 12 inch arm by the very nature of the physical size you should need less bias compensation then a 9 inch arm. And you should get less end of side distortion.
I use a two point gauge for setting my carts up, and I never set them up by ear, as mine are becoming less and less sensitive as I am getting older. I would rather trust my scope than my hearing.
S

[AlanS]

Skating itself does depend on the shape of the stylus and the quality/polish of the diamond.
It can vary quite a bit from the VTF setting...

But it's everybodys right not to care...


Thank you for your deep concern about my stylus and vinyl.

The TT was serviced by an ex Linn dealer about 6 months ago he used to train others. Took 5 days.

He reported the stylus was in excellent condition and did not need adjustment. I trust him, he's a vinyl lover and a friend of a friend.

[prestonchipfryer]

I generally set around 75% of tracking weight and find this is okay with my arm and cartridge for most LPs. I have test records and sometimes use them to check for inner groove tracking. But as with most things it's a compromise. :)

[Rare Bird]

Each arm is different around a sort of nominal average setting, each cartridge/stylus has different requirements and so the whole thing has to be fine tuned individually. I tend to use a blank piece of vinyl to get the basic setting and tune it from there, depending on the cartridge sample.

Thats it Dave that's what i do




I work within the Manufacturers recommendation, when im happy i then move onto the blank record (no groove) see if it drifts 2/3rds down the disc..i don't set it by that it's just peace of mind to see it not drifting..

[Thermionic Idler]

When will you reveal?

Firstly thanks so much to everyone for replying and voting so far, apologies for missing the fifth option of setting to the same indicated value as the VTF --- it's been a few years since I've seen an arm with a graduated antiskating dial so I'd forgotton about that!

At the moment it's neck and neck between the HFN test record and ear usage which is interesting, I'd have thought the unmodulated vinyl method would have been most popular but shows you can't assume anything!

Why did I bring it up? With both Koetsu and SPU cartridges the Schick produces a beautiful sound, but its lack of antiskating provision is beginning to cause me concern. I did question it before purchase too, but took the decision to trust the designer based on research into other arms like the Shindo and professional Telefunken broadcast arms which were all anti-skate free. The thinking is that longer effective length and lower cartridge compliance should render anti-skate largely superfluous, so you can remove a potential source of resonance. The Stereophile reviewer didn't seem to find an issue with it either and I heard no issues during audition.

However on occasions where the stylus is trying to read very tricky passages, I have noticed a fairly consistent tendency for the right channel to 'let go' before the left. To be fair it's quite a rare occurrence. What's causing me more difficulty is cueing - I'm now hand cueing a lot of the time because quite frequently if I set the stylus down using the cueing lever, it hits an un-grooved section and is pulled towards the centre with such force that it skips over the lead-in grooves and lands in the music. This has happened with both the SPU (3g VTF) and the Koetsu (1.9g VTF) and can't be good for stylus or LP's!

I wish more than anything that I wasn't having this issue because I pretty much cannot fault the Schick's sound. I also know that Les @ Walrus Systems in London recommends running Koetsu's sans anti-skate for best sound. But it's with something of a heavy heart that I'm beginning to consider anti-skate equipped alternatives because of worries over the long term health of my cartridge and LP's, the former represented a significant investment and the latter are irreplaceable. Hence my other thread over in the Idle Vice forum about the Audio Origami PU7.

[RobbieGong]

BTW- Surely one of the vote questions should be ' I set same as tracking force as popularly recommended' or something along those lines - surely :scratch: (Otherwise the votes incomplete - flawed for me :rolleyes: )

[Rare Bird]

No because pick-up arms have crap settings that cannot be relied on , the reason i would not rely on spring/dial settings...

[RobbieGong]

What ??? The vote is asking how we set anti-skate, and trust me, a lot of people set to the same as tracking force....

[Rare Bird]

Never!

[RobbieGong]

Never!

What do you mean by never ?

[Rare Bird]

I'm just puzzled why!

[RobbieGong]

I'm just puzzled why!

Now I'm puzzled why you're puzzled. I actually made my suggestion that setting to the same as VTF should surely be one of the questions before I noticed that Dave had already apologised for it not being included as a 5th option in the vote. I still think it should somehow be included. It is how plenty of people I am in no doubt set their anti-skate and like me the options available in relation to the question do not apply. Therefore, I and they cant vote - But hey it aint just about me or them is it !?! :eyebrows:

[AlanS]

Now I'm puzzled why you're puzzled. I actually made my suggestion that setting to the same as VTF should surely be one of the questions before I noticed that Dave had already apologised for it not being included as a 5th option in the vote. I still think it should somehow be included. It is how plenty of people I am in no doubt set their anti-skate and like me the options available in relation to the question do not apply. Therefore, I and they cant vote - But hey it aint just about me or them is it !?! :eyebrows:

Valiant effort but I think you sadly are wasting your time.

[Rare Bird]

Hi Alan although you choose to ignore my repeated PM.s +1

[AlanS]

Hi Alan although you choose to ignore my repeated PM.s +1

Hello
You might be sending but nothing arriving this end since your last mention of PMs.

[Thermionic Idler]

Unfortunately I can't find any means of adding that option after posting the original one. Which I suppose would make sense... you don't add candidates to the local council elections in the last hour before the polls close do you? :)

I did try to add all the options I could think of but as I said, it's been some 15 years since I last used an arm with a graduated anti-skate dial (on the SL1200's I used to have) so it didn't come to mind I'm afraid.

[Marco]

I use my ears to judge the setting of the bias, the same as I do (ultimately) with every other adjustment parameter on a turntable... Once the alignment protractors and stylus scales, etc, have done their job (all they can do is get you in the right ball-park area), final fine-tuning, to ensure that the T/T is performing optimally, should always done by listening! :exactly:

Oscilloscopes? Pah! They belong in science labs or an equipment designer's workshop, not in a music enthusiast's listening room... How do musicians tune the instruments they play? They use the the God-given organs at the sides of their heads (in conjunction with their brain)! Well, it's no different for an experienced audio enthusiast (who knows exactly what to listen for) when fine-tuning the sonic presentation of the components in his or her hi-fi system.

Ultimately, I always trust my ears, as they've rarely let me down :)

In terms of anti-skating, in my experience, the optimal setting is rarely the same as the preferred one for VTF - it is almost always LESS than that, but not by a huge margin. For example, on a cartridge that tracks at 2g, I'd expect the optimal bias setting to be somewhere between that and 1.5 on the anti-skating dial. The bias, for use with my SPU, is set at 2.7, on the dial, and the VTF is set at (the optimal) 3g.

However, Andre's right - the thread and weight arrangement for adjusting anti-skating, should your tonearm use it, is much better than any spring-loaded dial.

Marco.

[Rare Bird]

That your new Merc in Avatar, Marco?

[RobbieGong]

That your new Merc in Avatar, Marco?

Yeah, Why no more Techie Avatar Marco ? :)

[Marco]

That your new Merc in Avatar, Marco?

Yeah, dude, it's my new baby: a C320 Avantgarde Sport SE estate. 3.2L turbo-diesel, 225BHP, 150MPH, cruising machine. I love it! :)


http://img542.imageshack.us/img542/2043/mercw.jpg (http://imageshack.us/photo/my-images/542/mercw.jpg/)

I need to do some proper pics of my own. That's it outside the dealer's where I bought it from. Here are a few more of the interior:


http://img809.imageshack.us/img809/9362/mercspeedo.jpg (http://imageshack.us/photo/my-images/809/mercspeedo.jpg/) http://img822.imageshack.us/img822/7604/mercinterior2.jpg (http://imageshack.us/photo/my-images/822/mercinterior2.jpg/)


http://img546.imageshack.us/img546/7388/mercinterior3.jpg (http://imageshack.us/photo/my-images/546/mercinterior3.jpg/) http://img442.imageshack.us/img442/603/mercinterior.jpg (http://imageshack.us/photo/my-images/442/mercinterior.jpg/)


Marco.

[Marco]

Yeah, Why no more Techie Avatar Marco ? :)

Lol... Just a temporary wee change, matey!

Marco.

[Rare Bird]

im suprise tbh..

W0ijHj4VjU8

[Yomanze]

I have an acrylic mat that is perfect for setting anti-skate, just adjust until the tonearm stops moving. :)

[Marco]

im suprise tbh..

W0ijHj4VjU8


Love it! But unfortunately classic cars aren't very practical. I need something that will get Del and I, and my mum and dad, over to France and Italy on holiday, reliably and in comfort, and most importantly, that has plenty of room for bringing back wine and goodies...! :eyebrows:

The Merc has all the necessary toys: automatic transmission, sat-nav, air-con, cruise control, on-board trip computer, electric (memory) seats, parking sensors, Xenon headlights, tinted rear windows, 8-CD changer Harman Kardon 'surround sound' stereo, etc, etc :)

We still have Del's Morris Minor Traveller, for Sunday afternoon drives in the summer around North Wales. The Moggie will be getting some much needed TLC soon!

Marco.

[Rare Bird]

im suprise tbh.. Don't want to hear bollox excuses LOL...maybe upgrade in the futures! :D

[Marco]

Hahaha - aye! I'd love to treat myself to nice vintage Aston Martin, or perhaps a 1963 Alfa Romeo Guilietta:


http://img854.imageshack.us/img854/7458/alfaromeogiuliettafrfli.jpg (http://imageshack.us/photo/my-images/854/alfaromeogiuliettafrfli.jpg/)

Pure sex!! :eek: :stalks: :stalks:

But again, that would only be for sunny Sunday afternoons, driving around the local lanes!

Marco.

[Rare Bird]

Sorry i was so long had to change my panties :eyebrows:

[Marco]

Hehehe... I thought that they were rubber and 'moisture' proof? :D

Marco.

[Rare Bird]

:eyebrows:

[walpurgis]

Andr'e I saw your "MCs are cack" comment. I could change your mind if you heard my MCs and I'm an ADC user too like yourself.

Anyway regarding 'anti skating' I just use what sounds right, you soon know when it's wrong, you get horrible noises. I used to find conical tipped Deccas the most sensitive to this.

Its a balancing act between downforce and bias anyway, play it by ear I say.

[OneyedK]

Oscilloscopes? Pah! They belong in science labs or an equipment designer's workshop, not in a music enthusiast's listening room... How do musicians tune the instruments they play?
It's a bit sad to see that a lot of objective measurements are "forbidden" arts here.
It takes a while to train your ears to be able to do subjective (and more or less) correct measurements while adjusting setup.
In the case of anti-skating, an oscilloscope can be a valuable measurement device. Besides, people who use an oscilloscope will use their ears at the same time. To know what correlation exists between what they see and what they hear. It's more likely to achieve perfect (does that even exist?) setup using the proper measurement equipment, than without it.
I'm not claiming that everybody NEEDS proper measurement equipment, but it certainly helps...

Another setting that is hard to do without measurement equipment, is azimuth. With the naked eye, you can get close. With you ears, you can do nothing. (you can hear if it's wrong, but there's no way to know in what direction you need to correct.)
Adjust it with Adjust+ and your ears will tell you that it's perfect.

And How do musicians tune the instruments they play?
Well, in the real world, often the ears can be used, very often a strobe tuner is used as well. But it's not cool for them to talk about it either... :(

[Marco]

Hi Karl,


It's a bit sad to see that a lot of objective measurements are "forbidden" arts here.


Not forbidden (far from it), but on AoS we promote the use of one's ears, as the final arbiter, when assessing the sonic performance of audio equipment. Objective measurements may be used up until that point, but our view is that our ears should always have the final say on what sounds most 'correct' to the listener.


It takes a while to train your ears to be able to do subjective (and more or less) correct measurements while adjusting setup.


Indeed... That is why there is no substitute for experience! ;)

But how do you acquire the necessary experience if you don't allow your ears to make some of the important decisions? You have to 'train' them to know what to listen for, and when you succeed, in my experience, the results are more trustworthy in 'real world' applications than those achieved by man-made measurement apparatus alone.


In the case of anti-skating, an oscilloscope can be a valuable measurement device. Besides, people who use an oscilloscope will use their ears at the same time.


Sure, but I wouldn't know which way round to hold an oscilloscope, let alone know how to make sense of the readings! I'm being slightly facetious, of course, but as a staunch subjectivist and non-technical person, using test equipment just doesn't come naturally, especially as I get superb results already, simply by using my ears, together with 25+ years experience of setting up turntables.

Also, how much does a decent oscilloscope cost? Chances are, I'd rather spend the money on records! :D


To know what correlation exists between what they see and what they hear. It's more likely to achieve perfect (does that even exist?) setup using the proper measurement equipment, than without it.


Well I guess much would depend on the accuracy of the measurement equipment used, and the ability of the user to interpret the results equally as accurately, versus his or her ability to achieve the same results or better, simply by using their ears.

Often, for example, I've been able to determine, simply by listening, when a cartridge is tracking at the optimal VTF, only for it later to be confirmed by measurement, on digital stylus scales. I've also done the same with cartridge alignment, where I've determined, through listening, where the optimal position should be, as indeed confirmed later by a protractor. I enjoy testing myself like that!

Don't get me wrong, I'm not anti-measurements, but for me their use will always be secondary in importance to the results achieved, in the final analysis, by listening. What I'm against is people becoming lazy and shunning the use of their ears in favour of what test equipment says, simply because the results achieved by the latter may superficially seem more accurate.


Another setting that is hard to do without measurement equipment, is azimuth. With the naked eye, you can get close. With you ears, you can do nothing. (you can hear if it's wrong, but there's no way to know in what direction you need to correct.)


Indeed, although you're also relying on the accuracy of the headshell spirit level used, which in reality isn't terribly brilliant, and also that it's only measuring what is level at one specific point. What if the armboard that the tonearm (and thus headshell) is fixed to isn't 100% level? The reading you get then, in order to determine the correct setting for azimuth, will be false.

Yes, I use a spirit level to adjust the azimuth on my cartridge, but only to get the setting in the correct ballpark area. The final fine-tuning is always done by ear (in my case, through a very revealing set of headphones), where the optimal level of anti-skating is also determined, using my usual test music, as the arbiter.


And How do musicians tune the instruments they play?
Well, in the real world, often the ears can be used, very often a strobe tuner is used as well. But it's not cool for them to talk about it either...

Lol... Probably not. However, what do you think they did before strobe tuners were invented? Some of the best musicians that were ever born, and who produced the most amazing music the world has known, used their ears to tune the sound of their instruments, and the validity and success of that testing methodology still exists today, in both the worlds of musicians and audio enthusiasts alike :)

Marco.

[OneyedK]

Also, how much does a decent oscilloscope cost?
Not much, a cheap digital (PC/USB) two channel scope will do.
In the low frequency domain, they are fairly accurate and both channels will have the same errors.
Besides, we're not looking for absolute measurements, but relative measurements. (difference between channels)
I wouldn't buy an oscilloscope just for setting anti-skating.
But it's a valid and correct method.


although you're also relying on the accuracy of the headshell spirit level used
Errrrr? No, I rely on the measurements, both of amplitude and phase.
With phase being the most important...
And yes, a decent headphone can help a lot in this case, but the measurement of Adjust+ is so good, I cannot improve it by ear.


However, what do you think they did before strobe tuners were invented?
They had big problems in those times, but a lot of time to solve them.
Getting an orchestra to play "in tune" was a big part of the job.
And only a limited number of singers could cope with the pitch they were tuned in.
Contrary to popular belief, not all great musicians had (have) "absolute" hearing.
So they also had to take a reference and tune from there.

I think both subjective measurements (ears) and objective measurements (machines) have to go hand in hand.
Besides, this would save a lot of people heaps of cash.

[Marco]

Not much, a cheap digital (PC/USB) two channel scope will do.


How much is "not much"? Let's discuss figures. How many records could I buy for the price of a decent oscilloscope?


I wouldn't buy an oscilloscope just for setting anti-skating.
But it's a valid and correct method.


Yup, for you it is. I'd have little or no use for one. It might make a nice ornament though, lol! The "correct" method, for me, will always be that which, in the final analysis, creates the results my ears determine as being 'correct'. It's as simple as that :)


Errrrr? No, I rely on the measurements, both of amplitude and phase.
With phase being the most important...


Sorry, I wouldn't even know what that was, in relation to ascertaining the correct setting for anti-skating, let alone how to measure for it! In that respect, my friend, we live in different worlds.


They had big problems in those times, but a lot of time to solve them.


Well, I'm not short of time, and the best things in life are often worth waiting for! ;)


Getting an orchestra to play "in tune" was a big part of the job.
And only a limited number of singers could cope with the pitch they were tuned in.
Contrary to popular belief, not all great musicians had (have) "absolute" hearing.
So they also had to take a reference and tune from there.


Sure, but there's probably a valid reason why the best all-analogue recordings and musical performances (particularly in the jazz and classical musical arena), from the 1950s are, sonically, unsurpassed today - and one of those reasons is how the musicians and recording engineers of the day were absolute masters of their art, trusing their ears and experience to achieve the superb results that they did.

Would today's measurement apparatus, if they'd had access to it, have produced even better results? I'm not so sure, particularly if they got lazy and started using said 'gadgetry', as a matter of course, and relied on it, more than their ears and collective experience - thus stifling natural flair and artistic creativity in the process, the latter which I'll always care much more about with sound or music than any 'measurist's' notion of 'technical accuracy'....


I think both subjective measurements (ears) and objective measurements (machines) have to go hand in hand.


Not "have to" - only if such an approach suits your mentality and/or technical abilities. For the majority of today's audio enthusiasts, who aren't technically minded and have little interest in an objective approach to audio (count me in), that won't be the case.


Besides, this would save a lot of people heaps of cash.

Only if they're comfortable with using complicated measurement apparatus (and I mean anything more complicated than operating an alignment protractor or a set of stylus scales), and thus can derive an accurate meaning from the test results, and put it to the best use when setting up their turntables. Like I said, that's unlikely to apply today to the majority of end users of audio equipment, whose main interest is in listening to music, not pissing around with oscilloscopes.

Marco.

[AlanS]

Besides, this would save a lot of people heaps of cash.

what heaps of cash? My stylus is new I have a spare and my discs sound fine. My bowel movements are regular

[OneyedK]

what heaps of cash?
I was referring to people who experience "bad" sound and sell something that was simply not setup correctly.
I've seen a lot of people trying to solve audiophile problems by throwing cash at it.
--> I learned English from a book and Hollywood movies, it's possible that something get's lost or misunderstood in translation :)
Glad to hear your bowel movements are regular, especially during the holiday season :drunk:


How much is "not much"? Let's discuss figures. How many records could I buy for the price of a decent oscilloscope?
http://www.conrad.be/ce/nl/product/101672/Velleman-PCSU200-USB-oscilloscoop-2-kanaal-oscilloscoopvoorzetstuk-USB-scope/1113031&ref=list
€175...
Another option, for peepz not comfortable working with an oscilloscope is Adjust+.
http://shop.adjustplus.biz/
Slightly more expensive, but easy to use, most measurements are started automatically by a pilot tone on the test record.
And really, their method for setting azimuth is truly amazing.
Even if you don't want to use/buy it, have a read...
http://www.adjustplus.de/?lang=en
http://www.adjustplus.de/Download/AP_Azimuth_Compendium_english.pdf

btw, I'm not a dealer of all that stuff, just a very happy and convinced user ;)

[Marco]

I could buy quite a few records, Karl (especially second-hand ones), for €175. Which do you think I'd derive more pleasure from owning: those or an oscilloscope.....? ;)

Marco.

[prestonchipfryer]

What is the point of measurement? when your lugholes can tell you if things ain't right!

As for bowel movements;:eyebrows: AlanS means anal retention, which is a totally different matter.

[OneyedK]

AlanS means anal retention, which is a totally different matter.
Try Belgian beer, you'll know what I mean :cool:

[prestonchipfryer]

Try Belgian beer, you'll know what I mean :cool:

Cheers but I'm teetotal. :lol:

[Thermionic Idler]

What I worry about is the fact that my ears are good but my sonic memory is crap. Sometimes I make a change to VTA and ...... hear no difference whatsoever. Or 'imagine' that I did hear a difference. But is it better or worse and did I just imagine it? :doh:

Doesn't help when VTA adjustment consists of taking off the needle, applying the stylus guard just in case, undoing an Allen bolt, watching the arm slip down further than you meant it to slip and try and move it back to where you think it was before plus or minus a bit....... it goes on.

And yet... somehow you instinctively know when things are right.

I prefer to use measurements to get things in the right ballpark and confirm with my ears whether things sound right or not. If they don't, then heave a big sigh and start tweaking.

[Beobloke]

My oscilloscope cost me £12 at a car boot sale....

Nice Merc, Marco! (with the tiny exception of the rear 'privacy glass' which I detest!)

[RobbieGong]

What I worry about is the fact that my ears are good but my sonic memory is crap. Sometimes I make a change to VTA and ...... hear no difference whatsoever. Or 'imagine' that I did hear a difference. But is it better or worse and did I just imagine it? :doh:

Doesn't help when VTA adjustment consists of taking off the needle, applying the stylus guard just in case, undoing an Allen bolt, watching the arm slip down further than you meant it to slip and try and move it back to where you think it was before plus or minus a bit....... it goes on.

And yet... somehow you instinctively know when things are right.

I prefer to use measurements to get things in the right ballpark and confirm with my ears whether things sound right or not. If they don't, then heave a big sigh and start tweaking.

Totally understand what you are saying. Some carts are very vta sensitive too in my experience and where with the stock Techie arm I've found the sweet spot in the tiniest of turns as well as making setting vta a piece of cake. It's why the on the fly of the stock Techie arm is Superb with a capital S. I so wish it was on all arms.

[Marco]

Nice Merc, Marco! (with the tiny exception of the rear 'privacy glass' which I detest!)

Lol... I know where you're coming from (it reminds me of something a 'bad-ass' drug dealer might fit), but it'll probably do a good job of keeping my parents cool in the back of the car, when we drive them to Italy in the summer :)

Marco.

[RobbieGong]

Lovely, fully speced tourer Marco, would suit my wife and the kids a treat :eyebrows: I also like the Audi's :)

[nat8808]

Lol... I know where you're coming from (it reminds me of something a 'bad-ass' drug dealer might fit), but it'll probably do a good job of keeping my parents cool in the back of the car, when we drive them to Italy in the summer :)

Marco.

Haha, people will think they are gangsters when you turn up.

[nat8808]

Lovely, fully speced tourer Marco, would suit my wife and the kids a treat :eyebrows: I also like the Audi's :)

I was amazed at how you could pick up a 4.2L Audi S8 Quatro for less than £6k already. Must be one of the biggest bargains out there, although the Lancia Thema turbos and Alpha Romeo 164s out there for a few hundred always tempt me for my first taste of luxury driving.

[nat8808]

My main concern with anti skate is mostly to prevent bent cantilevers so I adjust so that it doesn't feel any forces either way on a blank groove.

Just a quick thought and question, is the anti-skate Required different on the innere and outer grooves? As the circle gets tighter The forces should change so which anti skate methods are best at providing that curve? A spring at the end of linearity or perhaps a twisted thread ( like well tempered) anything else?

[Barry]

My main concern with anti skate is mostly to prevent bent cantilevers so I adjust so that it doesn't feel any forces either way on a blank groove.

Just a quick thought and question, is the anti-skate required different on the inner and outer grooves? As the circle gets tighter The forces should change so which anti skate methods are best at providing that curve? A spring at the end of linearity or perhaps a twisted thread ( like well tempered) anything else?

It is usually asssumed that since the frictional force between the stylus and the record groove is proportional to the velocity (of the groove under the stylus), the maximum anti-skating force should be applied to the outer grooves. This is what is done with SME's falling weight arrangement.

As to how much, again since it is proportional to the friction between the sylus and groove, it is proportional to the tracking force. In practice I find that half the suggested bias is sufficient. I don't use a blank disc - just set the bias to half the tracking force and use my ears.

[MartinT]

To properly adjust bias (anti-skate is a misnomer - if your arm skates while playing music, there is something VERY wrong with the setup), you need a test record. Set the arm's bias to the nominal setting on the dial/weight for your tracking weight, then play the standard tracking test. Carefully adjust the bias either way to ascertain that audible distortion is minimal. If everything is ok, play the torture test and repeat. Be aware that your cart may not track this test at all well. The technique remains the same: find the centre setting where distortion is minimal.

It's fine to use a 'scope for this, or even an app for your phone that listens and displays the sinewave. You can easily see if there is distortion at the peaks of the waveform. Highly useful and won't cost you much at all.

One point: USING A BLANK RECORD SURFACE WON'T WORK! The friction seen by a stylus in a groove and on the surface of a blank disc are markedly different. The stylus is not designed to skate on a blank surface and the bias setting you find with this method will be wrong. In fact, different stylus profiles need different bias settings as their contact patch in the groove varies, which is why older arms have different settings for spherical and elliptical stylii on their dials. You need a real groove!

[Rare Bird]

Martin
I don't set it using a blank disc, i use that disc to see if there's any unacceptable drifting, just peace of mind really.Ive always done this & had absolutly no problems what so ever.

[Barry]

One point: USING A BLANK RECORD SURFACE WON'T WORK! The friction seen by a stylus in a groove and on the surface of a blank disc are markedly different. The stylus is not designed to skate on a blank surface and the bias setting you find with this method will be wrong. In fact, different stylus profiles need different bias settings as their contact patch in the groove varies, which is why older arms have different settings for spherical and elliptical stylii on their dials. You need a real groove!

Good point Martin, and one which explains why one can't simply 'dial in' the tracking force into the bias adjuster. Elliptical stylii present a groove 'footprint' that is about half that of a spherical tipped stylus. Hence less bias is needed. I find an amount equivalent to half the tracking force to be a good start.

[Andrei]

I avoid the problem altogether. I never drive when it is icy.

[Marco]

If you wipe your botty properly, too, after doing a shatzen, you'll also avoid any skidmarks! :eyebrows:

Marco.

[Macca]

I avoid the problem altogether. I never drive when it is icy.

I thought we were discussing how best to express a hatred of Torville and Dean...

[Barry]

...
If you are using a 12 inch arm by the very nature of the physical size you should need less bias compensation then a 9 inch arm. And you should get less end of side distortion.


No, not true - it all depends on the transverse offset distance of the arm. The transverse offset distance is the effective length of the arm multiplied by the sine of the arm offset angle. The turning moment about the arm pivot, is given by the frictional force between the stylus and the record groove multiplied by the transverse offset. It is this turning moment that is conteracted by the bias control.

The transverse offset can be identical between arms having different effective arm lengths. For example: the SME M-9, M-10 and M-12 arms despite different effective arm lengths have the same transverse offset distance.

Personally I prefer the falling weight method to that using springs. Metal springs can have a sound of their own - and that applies to turntable suspension as well.

The amount of bias depends on the shape of the stylus used as well as the tracking force. I start with a bias value that is half the VTF and experiment from there. The suggested figure for bias equal to that of the playing weight, goes back to the days when most cartridges used a spherical stylus having a groove 'footprint' roughly double that of an elliptical sylus, and hence requiring greater bias.

[John Gordon]

Hi all,

There is a current trend to ignore biasing to compensate for skating forces as it "sounds better". I don't have a problem with that. People can do what they want if it they think it sounds better. What annoys me is when they try and justify it by saying skating forces don't exist, or when tonearm manufacturers do the same as an obvious cost saving measure. The only justification for not including an antiskating facility is if the arm is long and is used with conical stylii at high VTF. Skating force will still exist, but will tend to be overwhelmed by VTF and merely be a moot problem for uneven stylus and record wear.

Most tonearm manufacturers who provide calibration for antiskate, try and make it simple to use by providing a relationship between downforce and bias - ie 2g VTF uses 2 on the bias dial. This doesn't imply that the bias provided is 2g. It will be less, usually around a third of VTF, depending what the designer has decided is appropriate. Perhaps it would be better if the bias was calibrated as an effective torque at the stylus. Many manufacturers simply leave it uncalibrated.


Hi Barry,
You should maybe look again at how the skating forces are generated.

The longer the arm, the less the skating force. For a pivoted arm, as the effective length increases, the angle between the groove tangent and the line between stylus and arm pivot decreases, therefore the turning moment decreases for a given VTF, as it is dependent on the resultant of the forces, which does not remain the same. For a very long arm, or a tangential arm, the skating force approaches zero as the above mentioned angle approaches zero.

Similarly, as the variation between the above mentioned angle and the cartridge offset angle is reduced with a longer arm, tracing distortion is reduced. On the other hand, as the angle increases as the arm approaches the centre of the disc (or rather a point around 15mm beyond it), the tendency to skate increases.

The skating force is generally taken to be proportional to the VTF and the coefficient of friction between stylus and record. However with different stylii, the area of contact changes, so that the pressure varies, therefore the force is dependent on the area - a larger area equals a smaller force, all other things being equal.

Your transverse offset distance, or Linear Offset, as it is generally known, has no bearing on anti skate. Your are correct in saying it is the same for arms of whatever length with the same geometry, but that is all.

Hi Martin T

Anti-skate or bias, whatever you call it, is a result of inward forces generally called skating forces. I personally used to call it bias, but most call it anti-skate, which is fair enough, as skating is what happens when the stylus is not restrained by the inner groove wall and sufficient VTF or anti-skate (bias).

Using a blank area of disc may or may not work. it depends on the contact area of the stylus, which may or or may not be the same as the area when in the groove. Admittedly it is imprecise, but is good for illustrating the principle of skating force and the biasing necessary to compensate for it.

John

[MartinT]

Thanks for contributing, John. Are you in the industry?

[John Gordon]

Hi Martin,
I used to manufacture tonearms, stopped doing that 15 or so years ago, and have recently been dragged back to the fringes of analogue thanks to a couple of blogs I write. I am currently trying to make my escape again...

Read all about it here:
www.odysseytonearms.blogspot.com (http://odysseytonearms.blogspot.com)

John

[MartinT]

Ah, the fabled Odyssey. Cool!

[Barry]

Hi Barry,
You should maybe look again at how the skating forces are generated.

The longer the arm, the less the skating force. For a pivoted arm, as the effective length increases, the angle between the groove tangent and the line between stylus and arm pivot decreases, therefore the turning moment decreases for a given VTF, as it is dependent on the resultant of the forces, which does not remain the same. For a very long arm, or a tangential arm, the skating force approaches zero as the above mentioned angle approaches zero.

Similarly, as the variation between the above mentioned angle and the cartridge offset angle is reduced with a longer arm, tracing distortion is reduced. On the other hand, as the angle increases as the arm approaches the centre of the disc (or rather a point around 15mm beyond it), the tendency to skate increases.

The skating force is generally taken to be proportional to the VTF and the coefficient of friction between stylus and record. However with different stylii, the area of contact changes, so that the pressure varies, therefore the force is dependent on the area - a larger area equals a smaller force, all other things being equal.

Your transverse offset distance, or Linear Offset, as it is generally known, has no bearing on anti skate. Your are correct in saying it is the same for arms of whatever length with the same geometry, but that is all.

John

Sorry John I don't agree. The turning moment about the arm pivot depends on the linear offset, the shape of the stylus and the VTF. Regardless of the length of the arm there will always be a linear offset if the arm has an offset angle. The amount of bias for a given VTF is the same for the 12" SME arm as it is for the 9" arm.

[Dominic Harper]

Totally agree with John on this one.

[Beobloke]

I am currently trying to make my escape again...



As long as we see an Odyssey RP6 first.....;)

[John Gordon]

Hi Barry
I think you are confusing cartridge offset angle which is a fixed angle determined by the geometry chosen by the designer having a fixed Linear Offset, and horizontal tracking angle, which is simply the variable angle formed by the groove tangent and a line drawn from stylus to arm pivot, and which differs from the cartridge offset angle by an amount dependant on the chosen geometry and the length of the arm except at two null points. At all other points, and with increasing divergence outwith the record dimensions, they are not the same.

The Linear Offset as you say, can be seen as the radius about the arm pivot at which the stylus friction generates a torque, but the torque due to the skating force resultant acts at right angles to the stylus/arm pivot line at the stylus, and so, but only at the nulls, is in the ratio of linear offset to effective length. Therefore the longer the arm the less skating force needed.

As effective length increases overhang decreases, because tonearm geometry for typical pivoted arms neccessitates an overhang and offset to allow the orientation of the stylus and cantilever to the groove to be optimised for minimum distortion according to the geometry chosen for a particular record size, and they both decrease with increasing effective length

However, the skating force depends almost entirely on the overhang component for its generation, as an arm without cartridge offset, but with overhang will still skate. The reason being that the friction caused by VTF pulls the stylus in one direction and the stylus is constrained by the arm pivot, which is not in the opposite direction, and so the stylus wants to move inwards, the force causing this being the resultant of the above forces.

The easiest way to see this is to imagine a straight arm, no headshell offset, but with overhang, as it approaches the spindle and ultimately moves behind and beyond it due to the overhang. You can then see that the stylus would be dragged inwards, and the notional Linear Offset of an arm with a cartridge parallel to the groove at that point, becomes extreme.

John

[John Gordon]

Thanks Martin

Hi, Beobloke
RP6? unlikely.... stick with that RP1...

John

[oldius]

I am confused. That is all.

[Si74]

"Most tonearm manufacturers who provide calibration for antiskate, try and make it simple to use by providing a relationship between downforce and bias - ie 2g VTF uses 2 on the bias dial. This doesn't imply that the bias provided is 2g. It will be less, usually around a third of VTF, depending what the designer has decided is appropriate. Perhaps it would be better if the bias was calibrated as an effective torque at the stylus. Many manufacturers simply leave it uncalibrated."

Not in a negative way but I could understand this if it were made clear in the manual/instructions but I've never seen this so it's ???? to help the numpties?
& dials on an Oddity, I ask you

personally I just listen to what happens when I drop the arm onto the record & adjust accordingly. Most test records will be f----d after a couple of plays & anyone not classing them as useless 30 years ago probably has no idea how to set up a turntable..
however Rega think vta is trivial and lots of arms have no azimuth adj? so what do I know.

[Marco]

personally I just listen to what happens when I drop the arm onto the record & adjust accordingly.

Me too, and it really doesn't need to be any more complicated than that. Ultimately, trust your ears!

Much as I respect John's obvious technical knowledge on the subject, about 70% of what he's written has went sailing straight over my big daft nut!! :scratch: :confused:

;)

Marco.

[the engine]

I just took my anti skate off and I can't here any difference what so ever. No shift in balance...no added distortion when cranked up...NOWT !!
Just a thought though. If the inward force is a natural thing , why fight it ? Are we not then putting un natural stress on the workings of the cartridge by physically 'pulling' it against a natural force ?

[Rare Bird]

Me too, and it really doesn't need to be any more complicated than that. Ultimately, trust your ears!
.

+1 regarding your ears, people should use them more often.

All this getting too technical gets up my back, there's no need for the average joe to worry about headache technicalities that should be the headache of the manufacturer/designer.I am a believer of doing things right but some people :rolleyes:

[Marco]

...there's no need for the average joe to worry about headache technicalities that should be the headache of the manufacturer/designer.

Ain't that the truth, brovva! Adjust the fundamentals to the best of your ability, then simply trust yer lugs, worry not, and enjoy to the music!! :exactly:

Anything else, unless you have the right mindset, is liable to induce (unhealthy) neurosis.

Marco.

[walpurgis]

I agree with the foregoing 'keep it simple' observations and expressed a similar view earlier. You can make life as complicated for yourself as you like, but in the end, it's not so much 'you know when it's right', as you'll damn well hear when it's wrong! (same applies with tracking force, VTA and azimuth)

[RobbieGong]

I agree with the foregoing 'keep it simple' observations and expressed a similar view earlier. You can make life as complicated for yourself as you like, but in the end, it's not so much 'you know when it's right', as you'll damn well hear when it's wrong! (same applies with tracking force, VTA and azimuth)

Too true ! And thats why afterwhich you'll then know when it sounds right :)

[Barry]

Ain't that the truth, brovva! Adjust the fundamentals to the best of your ability, then simply trust yer lugs, worry not, and enjoy to the music!! :exactly:

Anything else, unless you have the right mindset, is liable to induce (unhealthy) neurosis.

Marco.


All this getting too technical gets up my back, there's no need for the average joe to worry about headache technicalities that should be the headache of the manufacturer/designer. I am a believer of doing things right but some people

Ah - in which case my reply to John is best left unposted, as I'm afraid it would be quite technical (of a similar nature to my 'Knowledge' article on cartridge/tonearm alignment). :rolleyes:

[Marco]

No, no, please continue, Barry. As long as John and you understand each other, that's all that matters! ;)

Marco.

[Rare Bird]

Thats right don't let anyone views detract you from the topic, Tchnicalities maybe important to a lot but i just pick out the basics i require/feel important to me.

[Barry]

Thats right don't let anyone views detract you from the topic, Tchnicalities maybe important to a lot but i just pick out the basics i require/feel important to me.

Sound good practice to me. :)

[walpurgis]

Go on, go all technical on us, we can take it!

Perfectionism is to be admired as long as it doesn't get to be obsessive.

[Barry]

Go on, go all technical on us, we can take it!

Perfectionism is to be admired as long as it doesn't get to be obsessive.

My approach to 'anti-skating' is as I described: for cartridges with an elliptical stylus, I start with a setting corresponding to half the VTF and experiment from there using my ears and conventional records. I don't use a blank disc, for reasons Martin explained, thought I understand the 'peace of mind' it gives.

My contention is with the statement that 12" arms need less in the way of bias than 9" arms.

[Rare Bird]

(I have to admit the blank disc idea is just idleness on my part)

How i would do it..

Set up roughly by manufacturers recomendations.

Select various unmodulated section of the record..with a small eye glass , slowly do a series of needle drops , the tip should fall dead centre groove..Adjust accordingly by adding or deducting bias.

Move to heavily modulated areas, this is a bit harder to monitor but should fall ok if the unmodulated sections work out..try to avoid your brain impoding as you settle with the best compromise across the whole recurd :)

[Si74]

It's really not an exact science. I have some very expensive mc's where the cantilever is slightly skewed? with not many plays, some due to excess bias , some due to not enough and none due to silly settings. Till they settle in who knows? A slight twist, a slight tweak on the bias.
Azimuth worries me far more than bias but even with a torch and huge magnifying glass, the cantilever on my Koetsu defeats my fading eyesight, the zyx picks up so much crud that the only answer is the occasional trip to J7 for an inspection/clean under his scope. To be honest my 42 year old love of vinyl is being sorely tested by some of the shit records I buy at 20 odd quid a pop, and this coming from someone who didn't own a cd player till about 15 years after they promised us the earth:-)

[John Gordon]

Hi all,
I'm a bit surprised at some of the responses to what was intended as a clarification (although perhaps not as clear as it might have been) of a subject that is generally misunderstood.

I was simply saying that the skating force exists, is easily seen, and for half a century the overwhelming majority of designers have incorporated a way of compensating for it, because if you don't, the VTF is not the same on both sides of the groove. End of story. That aspect is not a "sounds good" issue, just a fact.

Some people don't wish to understand why it happens, some people do. Some people think it doesn't matter, some people do. Some prefer the sound withbias some without. There are set ups that need less compensation, some more. Playing the same size disc, long arms need less than short ones.

By all means, if someone is confused by it, set it to the manufacturers recommendation, and forget about it, and if that doesn't work, get someone to do it for you. Or buy a linear tracker.

If you want a car analogy, given past content of the thread, consider sports car suspension and steering geometry. Most people know nothing about it, and don't care, but that doesn't mean the designers haven't thought about it, or that they pick numbers out of a hat.

However, if you wanted to play around with it yourself, it might be an idea to know why it was done the way it was before chopping and simplifying on the basis that your old Austin Cambridge didn't have any of that fancy bollocks and still managed to get round corners...

And, Barry, as the length increases, (with Linear Offset remaining the same), the overhang gets less and less, the offset angle gets less and less, the arc the arm travels approaches a straight line (thereby reducing tracking error), and the skating force approaches zero. Think about it. Therefore a longer arm needs less bias to equalise the VTF. Whether the difference is audible is another matter.

John

[oldius]

John

I certainly appreciated some of the technical input that you have provided I just didn't understand a lot of it and that is my fault, certainly not yours.

This thread in general has lead me to re assess my anti-skate application. I am now using the blank section of the hi-fi news test record as a guide followed by the first two test tracks; I can't believe that in normal use I would face something as difficult to track as tests three and four.

All three of my arms use a string and weight solution or a variation of it with no measure or guide as to the weight applied. In this regard, setting to the manufacturers recommendation becomes a bit of a guess so a test record and ears for me.

If you can offer any further advice for a luddite then I would definitely appreciate it!

[John Gordon]

Hi Oldius,
Most manufacturers offer some sort of guidance, even with string and weight. If you don't have that guidance, stick it in the middle of the range, play some female vocal with minimal or no accompaniment, (or some flute which is also revealing) and if you can't hear any edginess or imaging anomalies when tracking inner grooves, pour yourself a drink, put on a record you like, and sit back and enjoy it. If you hear edginess in the right channel, move the weight away from the arm pivot. If the left, towards it. If both, increase VTF. Then have that drink.

If you use a test record use headphones if you can, as that helps to hear any edginess with less extreme tracks. As has been said, using a test record a number of times can damage tracks on the record if mistracking is severe. Of course, the same applies to whichever record you use and hear mistracking, test record or otherwise.
John

[walpurgis]

I have some very expensive mc's where the cantilever is slightly skewed? with not many plays, some due to excess bias , some due to not enough and none due to silly settings.

Going off topic a bit. I have a dodge which has worked on a few cartridges with skewed styli. As long as the tip is still vertical and there's no twist out of alignment, give the cartridge a holiday for a few months with a small blob of 'blutak' holding the stylus slightly offset from straight in the opposite direction to the skew. This eventually resets the cantilever suspension slightly and takes the stylus back to it's central position. I have had success with a Goldring G800 a JVC Z-1S and a Grado FT+. Take care to remove all the blutak, as it can leave small bits behind.

[Qwin]

A lot of people do set the anti skate to the same value as the tracking weight. Mainly because the manufacturers often sugest this (as a starting point). You have to remember they want to paint there product in a good light and a significant proportion of their customers will not know how to set it optimally, so they give them something guaranteed to track whatever is thrown at it and they can then be satisfied with their purchase as it does not skip and in their eyes "tracks well". That does not mean to say it is correct for best sound reproduction, stylus and or record wear.

As for the pole, I think using the test record is relevant but the best way is to measure distortion, but we don't all have a scope or know how to use it. As for using an unused part of the record and finding the extremes at which the needle will be dragged one way or the other accross the record and setting at a value mid way between the two, this also has relevance. I personally set it as low as I can, till it starts to skip, then increase it slightly. As has been pointed out different shaped sylus run at different depths so can be more tolerant to skipping but the ideal setting is the same regardless of shape. And lets not forget, the required anti skate setting is continuously variable accross the record. Bit like trying to fix a knull point, it will only be right at a certain sweet spot.

If you really want to get it right, get a linear tracker :drool: which have their own set of issues.

[synsei]

What is your approach to Anti-skating?

I arrive at the ice rink armed with a baseball bat... :door:

[Andrei]

The easiest way to see this is to imagine a straight arm, no headshell offset, but with overhang, as it approaches the spindle and ultimately moves behind and beyond it due to the overhang. You can then see that the stylus would be dragged inwards, and the notional Linear Offset of an arm with a cartridge parallel to the groove at that point, becomes extreme.

John

John, that surely is what skating is. I once had a maths teacher who taught me a method of solving complex problems: - Make them simple. The way I see it is as you have described. Another hypothetical is to imagine a tonearm that was, say six inches *. It is going to have so much sideways force that it will be pushed off the record.

* Freudians: F off, I have a nine inch tonearm.

[Qwin]

John - your post #99

I think you have it wrong as I understand it. Applying anti skate does not REDUCE the difference in pressure between the inner v outer walls of the groove, it INCREASES the difference.

To explain, the outer wall pushes the stylus towards the centre of the record due to the point of contact in relationship to the curve of the groove. The record groove outer face is hitting the outside edge of the stylus as the record rotates. This causes uneven pressure between inner and outer walls and pushes the arm across the record.
To prevent the arm wandering off, designers incorporate a device (spring or weight) that pushes in the opposite direction to balance it out and prevent the movement. This force is pushing towards the outer edge of the record and is further increasing the force against the outer face of the groove.

This is why the lower the anti skate force you can run, the smaller the difference between the inner and outer wall side loading but there is allways going to be a difference even if no anti skate is used. Increasing the Vertical Tracking Force, (stylus presure) increases the load to both walls by roughly the same amount.

Someone shoot me in the head if I have this wrong, because this has always been my understanding of how it worked. :scratch:

[Barry]

And, Barry, as the length increases, (with Linear Offset remaining the same), the overhang gets less and less, the offset angle gets less and less, the arc the arm travels approaches a straight line (thereby reducing tracking error), and the skating force approaches zero. Think about it. Therefore a longer arm needs less bias to equalise the VTF. Whether the difference is audible is another matter.

All the while the arm geometry has a linear offset, there will be a clockwise turning torque about the arm pivot, caused by the friction between the stylus and the record groove.

The longer the arm, the smaller will be the offset angle, and so too will be the deviation from tangential tracking. The angular variation of this deviation across the record playing area will 'modulate' the offset angle and affect the linear offset and thus the turning torque. That is the turning torque, or bias, will not be constant across the record surface. But since the angular error is much smaller than the offset angle, there will always be a net bias inwards towards the centre of the record.

This is counteracted by an outward force applied to the arm by a thread and weight, or by a spring. Usually the bias calibration is related to the tracking force used (since the frictional force is proportional to the tracking force). Too little bias will cause mistracking on the right-hand channel, too much will cause mistracking on the left-hand channel.

[Qwin]

Some of these explanations are getting a bit wordy in the language of techno-speak. :lol:

I am sure I am not alone in wanting to grasp a basic understanding of this fundamental principle which non linear tracking arms have to work with.

Barry - If I can use the following diagram lets see if I have it right this time and put it in a way that the majority of us can relate to.

Let’s forget about grooves for the moment and just use a plain disc for the example:

http://www.jkwynn.co.uk/Pics/anti_skate_forces.jpg

If the stylus is dropped at location “1” the friction of the stylus on the rotating disc will exert a considerable force in direction “A” but very little in direction “B”.

If we were to do the same for location “2” the friction would apply a lot of force in direction “B” but little in direction “A”. So the arm would be pulled very sharply to the right.

This is the basic principle involved. Because of overhang you get a small but significant force in direction “B”. The greater the overhang, the greater the force and this is what the anti skate devices are trying to compensate for?

It would seem there for that the natural tendency is for the pressure to be exerted against the inner wall of the groove and that the anti skate pushes towards the outer wall to try and balance things out?

Sorry for dumbing it down but we can’t all keep up and I’m sure many would feel, as I do, a lot happier when setting things up if they had a little bit of a clue as to how it all works in principle. We see the arm wonder across the record, nice if some of the mysticism can be removed. I include myself in this.

I can see what you are saying about the constant change across the sweep of the arm but I am really just getting back to the fundamentals here. :cool:

[Barry]

Hello Ken

It’s difficult to comment on your diagram and subsequent argument, since for any straight arm (that is, one that does not use an offset angle in its geometry), minimum tracking error is achieved through the use of stylus underhang, whereas cranked arms that use an offset angle, achieve minimum distortion through the use of stylus overhang. (H. G. Baerwald ‘Analytic treatment of Tracking Error and Notes on Optimal Pick-up Design., J.S.M.P.E., December 1941, pp. 591 – 622).

All modern pivoted pick-up arms use both an offset angle and stylus overhang; and it is the combination of offset angle along with the effective length of the arm that gives the arm a linear offset. If you imagine a line projected through the cantilever, back to the pivot plane, this line along with the line representing the effective length of the arm (from pivot to stylus point), will form a right-angle triangle. The short side of this right-angle triangle is called the linear offset (= L.sin θ, where L is the effective length and θ is the offset angle).

The turning torque or bias is then given by μT.Lsinθ, where T is the tracking force and μ is the coefficient of friction between the stylus and the record groove. Thus the bias is proportional to the tracking force.

The longer the arm, the smaller the value of θ, but for any arm of finite length the value of θ will be finite (~ 18° - 24° according to Baerwald (IEC)) - so too the bias.

[Qwin]

Wooooow, Barry back up man. Have you any idea how many vinyl lovers just glazed over and reached for the CD remote? :D

I was suggesting we keep it to general principles explained in a way we can all understand. “(= L.sin θ, where L is the effective length and θ is the offset angle)”.
Come on, who actually uses the maths when setting up a cartridge. Baerwald and Co did this for us and the maths is only there to prove the principle anyway. Most people just want to understand the principle, not the maths.

I think we were talking at cross purposes to an extent. I was trying to demonstrate and explain forces relating purely to anti skating and put it in an easily understood way. I was not referring to alignment and offset and is why my example proposed a plain disc without grooves.

Although you say it is difficult to comment on my argument, you kind of did, in a round about way and suggested I was on the right lines, which I appreciate.
I am referring to the overhang. The greater the overhang the greater the bias towards the centre of the record, for the reasons I gave. Also that because the friction of the stylus and its relevant position on the revolving disc causes this bias, increasing the tracking weight, increases the friction, which increases the amount of bias towards the centre.

The alternative scenario is if the stylus is underhung and its contact point on the revolving disc is more akin to the lower left quadrant in my diagram. Here the bias is towards the outside edge of the disc, the greater the distance the stylus is underhung the greater the bias towards the outside edge. This explains why some anti skate controls have plus and minus values. Many people struggle to understand this concept. No maths needed, just a simple explanation with pictures.

I appreciate the overall scenario is complex and the temptation is to try and give an accurate but technical explanation, the thing is there’s not much point if you loose half your audience along the way.

Just keep hitting me over the head Barry, eventually some of it will sink in. ;)

[trio leo]

I've read through all 109 posts and I feel I'm still a little confused, varying opinions and methods coupled with some obviously experienced techie stuff that went over my head.

I must have had the VTA and azimuth correct on my Trio L07D, because I often tried anti skate ON and OFF and I couldn't hear any difference, NOTHING changed, no sibilance, no distortion left or right, no shifting of sonic image and I got the same results using an SPU at 3g or another MC at 2g.

I feel I SHOULD be using anti skate for peace of mind, but I'm still not sure whether it matters, as many records I've had for 30 years still sound great.

Though I do accept I'm a numptie when it comes to technical stuff and I maybe missing the salient point.

When I get my td 124/11 set up in it's new plinth I am going to take some time, with an eyeglass and listening to get the best results.

If I use the anti skate I will trust Audio Technica know what they're doing and set the weight mark the same as the tracking weight.

enjoy your music

regards Al

[John Gordon]

Andrei
You have it right.

Qwin
you also have it right in your second post with the diagram, the groove does guide the stylus, but the inner face of groove has a greater share of the VTF, which is why antiskate pulls the arm outwards, and why cartridges with high tracking forces appear to need less antiskate, as the high force keeps the stylus securely in the groove, albeit still with different forces on each face.

Trio Leo ( and anyone else)
For peace of mind, set bias as recommended by the arm manufacturer. The bottom line is that there is a skating force in all pivoted arms which will result in more downforce on the inner face of the groove and less on the outer. The inner may wear faster due to the increase, or the outer face due to intermittent mistracking. When VTF is reduced to a point where it is less than the inherent skating force, the arm will skate, so avoid setting VTF below the manufacturer's recommended level. These are physical aspects of replay.
If anyone thinks their system sounds better without antiskate and wish to set it like that, fair enough. In the same way, and for the same reasons you might, for example, set the speed of your deck at 35rpm...

Barry
(and anyone else who is interested in the technicalities, otherwise ignore):)

Your description is correct up to a point, and so I don't see why you feel you need to disagree with me, except that you are still confusing cartridge offset with horizontal tracking angle, which is why you are stuck on linear offset.

The angle of the cartridge offset is chosen by the tonearm designer based on assumptions of record dimensions and tonearm length. It is found, as you say, using various formulae. The record dimensions give both nulls and linear offset. The cartridge offset angle at the nulls is calculated using the desired effective length and the linear offset. A corollary of this is that, for a given alignment, both the nulls and the linear offset remain the same for all effective lengths.

The point to note here is that the cartridge offset is equal to the tracking angle only at those points, and only because the designer chooses it to be so. Anti-skate is a result, not of cartridge offset angle, but of the tracking angle, i.e. the angle between the groove tangent at any given point and a line from arm pivot to stylus, which is dependant on the overhang, not the cartridge offset angle. This is a physical fact, not a designer choice, which is why Qwin's example using straight arms is perfectly valid.

John

[Barry]

No, I’m not confusing offset angle with the tangential tracking error angle. Figure 1 of http://www.audiomods.co.uk/papers/randhawa_pickupdesign.PDF , I hope, makes this clear. It also supports my claim that the side thrust (Fs, in the notation of Fig 1), depends on both the offset angle and the tracking error angle; the latter of which tends to modulate the former, but being so much smaller than the offset angle means bias compensation is required for all pick-up arms of a finite length.

The clockwise turning torque caused by the frictional force between the stylus and the groove and the offset geometry of the arm is shown in the figures towards the bottom of page 5 of:
http://dl.dropbox.com/u/66369472/SME%20Series%20II%20pickup%20arm%20leaflet.pdf .

The bias correction provides an anti-clockwise torque to counteract this.


I’ll stop now, as I don’t seem to be helping anyone with this thread.

[John Gordon]

Barry
Thanks for that link to the Randhawa article in Wireless World. I have the original in my files. I'm glad that you are aware of the difference between cartridge offset angle and tracking angle.

Therefore you should be able to see that the point is that antiskate has nothing to do with cartridge offset but everything to do with tracking angle. The diagram you quote makes this perfectly clear in the inner grooves where the angle referred to is D+alpha, which simply is acknowledging the fact that the tracking angle is not the cartridge offset, and is increasingly not so with reducing radius. The variable is the tracking angle not the cartridge offset. The fact of the difference being called tracking error acknowledges that cartridge offset is not the relevant factor.

Of course bias is required for all arms of typical effective lengths. There are very few 100 cm arms. However, the point is that linear tracking arms need no bias because they are effectively a pivoted arm which is infinitely long, therefore need no offset nor overhang, and so illustrate the result of increasing effective length. All arms need some antiskate. The amount and the extent to which it varies accross the record wil depend on the specific arm and record. A 9" arm set up for LPs but playing a 7" single for example will need lots. A 12" arm set up for playing 7" singles will need hardly any.

Regarding the torque produced by friction, of course there is a torque as referred to in the SME sales blurb you link to. The point under discussion is how that is generated, and in the SME sheet it refers to the arm, as opposed to the cartridge, being offset, although explaining it in this way simply confuses as it gives no explanation or mention of what the arm is supposed to be offset to, which doesn't help. What it is saying is that the arm pivot is offset from the groove tangent, and any torque will be a function of that, ie the tracking angle, which varies with overhang.

The bottom line is that if you set an arm with zero overhang, where overhang is defined as being the distance a stylus is beyond a line passing through the spindle perpendicular to the stylus to arm pivot line, then it will experience no skating forces, whether it has cartridge offset, and thereby linear offset, or not.

But perhaps this is enough of this all this stuff. It probably only serves to alienate.

I am sure we are agreed that the main point is that people should use antiskate, whether they can hear a benefit or not. It should be the default position, unless, basically, they are convinced it is the work of the devil and their records and stylii are made of material that is infinitely long-lasting, irrespective of what they subject them to. Good luck to them.

Using minimal or no anti skate is a bit like recommending you drive your car until the tyres are almost worn out and are only just gripping and no more, as that's where it handles best.... !

John


John

[Barry]

We're probably closer than you think. It all comes down to terminology; my 'obsession' with offset angle, rather than tracking angle, is because the difference between the two is small. This difference is ~ 1.7 degree compared with an offset angle of ~ 21 degree. The variation in side thrust across the record playing surface will be ~ +/-7%.

The SME diagram should be seen as showing the offset of the cartridge, not the bending angle of the arm. In that context, maybe the following diagram, courtesy of the vinylengine, might be germane (some of the Greek characters do not come out properly, but the text can be understood nonetheless):

http://web.eject.co.za/s8nspawn/hifi/skatef.pdf

The first person to sensibly discuss bias and its correction was John Crabbe. He wrote about his thoughts in "Dynamic Side-thrust in Pickups", Wireless World, May 1960, where of course, he outlined his 'weight on a thread' bias compensation method. (I can't find a copy of this article. Do you have one? If you do would you mind scanning it and putting it on the forum?)

Regards

[WOStantonCS100]

I've got me one of these thingamacheesenuts and can't seem to find the anti-skate dial. :scratch: Every now and then I take another look to see if one pops up. Nothing yet. :D

http://www.trans-fi.com/Terminator%20III/Tomahawk/T3Tom1.JPG

[Qwin]

Hi Bif, the "Terminator" is what I will be using on my current SL-1200 II project.
Vic at Trans-Fi very kindly leant me a non working assembly to use for establishing my mounting points in the plinth. What a nice chap! :)

[John Gordon]

We're probably closer than you think. It all comes down to terminology; my 'obsession' with offset angle, rather than tracking angle, is because the difference between the two is small. This difference is ~ 1.7 degree compared with an offset angle of ~ 21 degree. The variation in side thrust across the record playing surface will be ~ +/-7%.

The SME diagram should be seen as showing the offset of the cartridge, not the bending angle of the arm. In that context, maybe the following diagram, courtesy of the vinylengine, might be germane (some of the Greek characters do not come out properly, but the text can be understood nonetheless):

http://web.eject.co.za/s8nspawn/hifi/skatef.pdf

The first person to sensibly discuss bias and its correction was John Crabbe. He wrote about his thoughts in "Dynamic Side-thrust in Pickups", Wireless World, May 1960, where of course, he outlined his 'weight on a thread' bias compensation method. (I can't find a copy of this article. Do you have one? If you do would you mind scanning it and putting it on the forum?)

Regards

Hi Barry,
I'm not old enough to have got the 1960 article... thankfully, but if I do come across it I shall post it.

I had a look at the diagram you linked to. It is a bit misleading as it shows the straight arm with underhang. If the offset arm had been set up similarly the variation in skating forces would have been similar. The arm pivot doesn't care whether the cartridge is offset or not. It is subject to the same torque.

I'm sorry to keep on about this, but I think our discussion is useful, as there are those who advocate not using any anti-skate, on the basis that it either doesn't exist, sounds better without it, or, worse, that it is some arcane theory that can be ignored in order to maybe even reduce manufacturing costs and enable arms to be supplied without it....

Therefore to try and explain clearly, as I'm sure we both are trying to do, is well worth it.
John

[Barry]

Hi Barry,
I'm not old enough to have got the 1960 article... thankfully, but if I do come across it I shall post it.

I had a look at the diagram you linked to. It is a bit misleading as it shows the straight arm with underhang. If the offset arm had been set up similarly the variation in skating forces would have been similar. The arm pivot doesn't care whether the cartridge is offset or not. It is subject to the same torque.

I'm sorry to keep on about this, but I think our discussion is useful, as there are those who advocate not using any anti-skate, on the basis that it either doesn't exist, sounds better without it, or, worse, that it is some arcane theory that can be ignored in order to maybe even reduce manufacturing costs and enable arms to be supplied without it....

Therefore to try and explain clearly, as I'm sure we both are trying to do, is well worth it.
John

Haha – I wasn’t suggesting you were old enough to have read the WW article at time of publication, I just though being an arm designer you might have a copy as part of your reference material.

It’s interesting that a straight arm without offset or overhang is always tangential to the groove and does not suffer any bias either inwards or outwards. Despite this, the geometry is not used as the stylus mounted on such an arm traces an arc as the arm moves from the outermost groove to the innermost; whereas of course the record was cut along a radius, the chord to the arc described. What this means is the replay stylus will slowly advance along the groove as the pivoted arm swings inwards from the outer groove. It reaches a maximum in the middle of the arc, with the error corresponding to the sagittal distance between the arc and the chord.

Clearly this geometric sagittal error causes a phase and timing error, so Percy Wilson et al. suggested the use of both overhang and cartridge angular offset. And this is my point – we have to consider practical arms, which as we agree, will suffer a tendency or bias in a direction towards the centre of the record.

One of the fallacies is that longer arms do not require bias compensation. They do, but the variation of this bias as the arm moves across the record will vary less than it will do with shorter arms.

[WOStantonCS100]

Hi Bif, the "Terminator" is what I will be using on my current SL-1200 II project.
Vic at Trans-Fi very kindly leant me a non working assembly to use for establishing my mounting points in the plinth. What a nice chap! :)

Hey Ken,

Vic certainly is a great chap to work with; superb customer service! I had the T3 on another turntable I was using for most of the year; but, have returned it to a 1200... ...as I've returned to a 1200 as my main table. With the MN bearing and wide swath of available upgrades (and the !sound!), I just can't seem to stay away.

I'm not sure I would call it "anti-skating" per se; but, I do level the arm (two screws on the right) so that when the cart is on dead wax it neither drifts to the left or the right when the record is spun. Not quite the same as skating force, though, considering how the stylus tracks the groove.