How to set SRA after determining true vertical?

Sorry about the first pic URL. Just paste the whole thing into your browser.

If all the cutting engineers had been that meticulous, we could almost set and forget!

Neil, how did you determine the 4mm => 1 degree? I'm not disputing it, just curious how you measured it.

Dan_ed,

I too am curious but, he is right. I drew it out in Corel Draw and he is right on the money.

Doug, I'll take that remark as a compliment? (unless informed otherwise.) Actually, this thread was partly inspired by the beautiful stylus pics you posted, plus people keep asking me how to do this. I know you adjust your SRA a lot, and I wish I could too, but the SME V was apparently designed in the "set it and forget it" days. I keep mine at 1.4 degrees which seems to work well for most recordings, but if anyone out there has an xtra Tri Planar for sale cheap, I'd be interested ;~))

Dan, I don't blame you for asking. It's quite simple really, and just a matter of geometry as you will see. Unfortunately, it would be a lot easier to draw it for you, but I'll try and explain it in words first, and maybe later I'll have time to make a diagram and post it. So please leave a post to let me know if the following makes sense to you:

A typical 9 inch TA measures 23 cm (or 230 mm) from the vertical bearing to the stylus tip. Imagine now that you lift your TA with the finger lift, but instead of setting it on the record, you just keep lifting it (magically of course) up and over the back of the turntable base, and continue under and up through the base to the armrest again.

OK? So you've just made a circle with the stylus tip; so far so good? The length of this circle's circumference (in millimeters) is PI times the diameter of the circle. The radius of the circle is 230 mm (the TA length) so the diameter is 460 mm. PI is 3.1416, so PI x 460 = 1445 mm (the length of the circumference traced by the stylus).

There are 360 degrees in a circle. So each (pie-shaped) degree of our circle would contain one three-hundred-and-sixty-eth of that 1445 mm circumference. Divide 1445 mm by 360 = 4 mm.

So if you raise the stylus end, OR THE BEARING END (which is what we need to do to create SRA at the stylus end) you are going to tilt the tonearm AND THE STYLUS (which is attached to it) exactly one degree!

If you have a cool tonearm like Doug's Tri Planar, you just dial up however many degrees (times 4mm) you want. If you're stuck with something less accomodating, I've found the best way is to use a stack of automotive feeler gauges to achieve the height you want.

Converting:

Angular Tilts To Linear Measurements

1 arc second = 0.0000048481232363502727814651700363688 inch per inch

= 0.000048 inch per 10 inches
= 0.000058 inch per foot

Linear Measurements To Angular Tilts

0.000001 inch = 0.20626480624702760022105769979869 arc seconds per inch

= 0.021 arc seconds per 10 inches
= 0.017 arc seconds per foot

Got it, Neil. The calculation makes perfect sense. Guess I was expecting that you had marked up some tiny protractor or something. I just have to run the numbers for a different arm length. This seems like another good method for getting started and then adjusting by ear. Fortunately, my Graham and TriPlanar both have VTA scales. The RB 250 I'm going to mount on a Lenco project doesn't have this but I plan on using an aftermarket Rega VTA adapter.

Could you also set azimuth by looking for a perfect "X" with one of those microscopes? Of course the microscope would have to be placed in front of the cartridge. Could this be a better method than looking at the cantilever and it's reflection in a mirror?

Ketchup, you are quite right, this is an excellent way to check azimuth. There is just one leeeetle setup problem you need to solve first:

If you just place the mirror on the platter, you'll never get a scope in there to look at the image because the platter is in the way. Here are two ways to overcome the problem:

1.) If your tonearm has the vertical bearing axis perpendicular to the headshell offset, then all you need to do is shim the mirror up on something about 3/16" thick like a piece of balsa wood or foam-core. Just high enough to let you rest the end of the scope on the platter and be able to see the stylus head-on.

2.) You could cantilever the mirror a half inch or so off the edge of the platter (taping it securely to the platter, AND taping the platter to the TT base so it can't rotate!) and this will also allow you to look at the stylus head-on.

Be very careful though! You might want to use a piece of masking tape to restrict horizontal movement of the tonearm.

Nsgarch,

Great geometry refresher, thanks! And yes, it was a compliment. As we probably all know, cutting engineers allowed a wide range of SRA's when cutting lacquers. If they'd all taken such care it would make accurate playback much simpler. Tonearm height adjustments could exactly = record thickness changes. That would be nice.

A naked-eye method for (fairly) precise SRA setting has been posted in the VA FAQ's for many years:

http://www.audioasylum.com/audio/vinyl/messages/1240.html

Jon Risch, the author, offers excellent technical explanations. After studying many different cutting lathes, he recommended that a good compromise SRA for "set and forget" rigs would be 2 degrees forward of vertical, ie, top of sylus pointed away from the tonearm pivot.

Before getting the TriPlanar I used Risch's method when setting up a new cartridge. It was an effective way to settle on a baseline arm height position. Now I'm spoiled. It's easier and more fun to twiddle while listening than to fuss with maglites and magnifiers.

Regards,
Doug

How lucky are we to have such a great venue like this.Nsgarsh,you have done it again,and the other Einsteins are also an appreciated necessity.Really!

Ohhhhhhhhhh, you guy's are making my head hurt. I knew I shoud have stayed awake in algebra class (I never even made it to geometry). I'll supply the beer if one of you will just come on over to my house and set my TT up!

Chris

Simple applied trigonometry. I just can't seem to think like an engineer any more after all these years of writing software.

Thanks again, Neil.

Dan, architecture (what I do to support my audio addiction) is all about geometry, so it comes quite naturally ;~))

As I have said before and nobody pays any attention. Probably becuase they think I'm wrong. Your record could care less about the cutting edge angle. What you want is maximum contact with stylus and grove. if you are lucky this will occurr when the headshell is parallell with the record surface.

When that happens you can then use the catridge angle as a tone control rocking it back and forth by raising or lowering the back of the tonearm. vtf can also change this angle. the more down force the more the cantilever will deflect. Stereo seperation is affected by antiskate and azimuth.what you want there is the the stylus riding in the direct center of the grove. easier for linear arms.

what's important then is the angle of the stylus not the angle of the cantilever. the stylus should be perpindicular to the rcord surface. If you took an xy graph and placed it on the record surface and placed the stylus at 0,0 or dead center and measured the angle in a 360 degree rotation you want 0 degree deviation all the way around.

Take a nail and dirve it into a board at a 90 degree angle about 1" from the end. You will see that the nail will be perpindicular to the surface. Now lift the end of the board 20 degrees. the nail is no longer at 90 degrees. you have two choices either bend the end of board 20 degrees or drive the nail in at 70 dgrees to compensate.

The cartridge and arm manufacturer do this for you as best they can. There are two variables they can't account for vtf and record thickeness. those two things must be accounted for by the end user. It might be easier if you chose the same cartrdge tonearm and turntable as the cartridge designer used.

Once you determinde the the arm is level by making sure the height of the arm is the same at the stylus, midlle and pivot hopefully the stylus is now perpindicular to the recocrd surface. You should be getting maximum contact with the stylus and grove as the cartridge manufacturer intended. My sme 4 provides a line through the middle of the arm for this purpose. You can then simply lower or raise the arm for different record thickness. Of course you should determine vtf before you finalize this process.

One additional variable is the mounting of the needle on the cantilever. If you examine a number of cartridges head on, you will find that the needles are not all set perfectly perpendicular to the cantilever or the headshell. Errors can be up to 3-4 deg. This is another reason why getting the azimuth and SRA right is not as simple as making the headshell perpendicular to the platter and leveling the arm etc. For azimuth, I would assume it is more important for the needle to be perpendicual to the record in the grove, than for the headshell to be parallel to the record surface. Anyone have any experience with this as well?

Zargon-the thrust of my argument is that SRA should be used to make the stylus perpindicular to the groove or record surface not necessarily mimmicking the stylus cutting head.
If I get you agree to that,I'm satisfied. How you get there is not that important. That will get you maximum groove contact and that is what you paid for.

I was just cautioning those who might not be sensitive to needle mounting variations. Their existence serves to strenghten the need to get SRA and azimuth close, and then make small adjustments either way while listening for the optimum setting. I really have no knowledge or opinion on whether the SRA should be vertical or 1-2 deg. forward, as Doug suggests. In my single case, it appears to end up vertical, but that is only one TT setup.

If you have a spherical stylus or even an elliptical sytlus, then the actual SRA is not too critical because whether the stylus is vertical, or leaning (less than a degree) slightly forward or backward, the very rounded tip is going to fit in the groove more or less the same way in all cases.

Such is not so for (the more common today) "micro-ridge" type styli, pioneered by Shibata and van den Hul. These styli are shaped a bit like a spade shovel, broad across the groove and thinner front to back. Their long edges touch the groove on each side, in a line running more or less from top to bottom.

The cutter head is VERY spade-shaped -- a chisel actually. It is not vertical either -- never has been, even with 78s. Why? Because if it were vertical, the cuttings it produces would jam between the head and the groove and ruin the master. Instead it is tilted forward (at the top, just like you'd do with a wood chisel) so that the cuttings keep "peeling" off and out of the way.

Therefore the "wiggles" the cutter cuts into the groove are all "leaning" forward as well as wiggling side to side.

If you have a "cutter-shaped" stylus (micro-ridge) and you want it to make the best contact or "fit" with the groove, it has to be tilted forward so that its edges match the forward-leaning groove wiggles. This angle of tilt is called the Stylus Rake Angle, or SRA. It is usually between 1 and 2 degrees for most recordings. But as Doug already pointed out, there is no actual standard, and cutting lath operators have some leeway in how they want to adjust the head for a particular recording, or perhaps use with certain brands of blank masters.

This is why I recommend adjusting the SRA to just under 1.5 degrees. Then, if you have a tonearm that's easy to raise or lower, you can "fine tune" the SRA for a given record -- increasing it for a thicker record, for example, or decreasing it if your ears tell you that maybe the lathe operator set the cutter closer to 1 degree.

A "vertical" setting would never do for a micro-ridge type stylus, because the edges of the "spade" would be straight up-and-down, and would actually scrape across the tilted wiggles instead of fitting into them.

Nsgarch- you make a convincing argument. your shovel and chisel anology could be true but they move in only one plane. the cutting lathe moves in two planes. I believe your analogy would be true if the cutting head were like a jackhammer titlted forward. Then each groove would be cut from the top with the resulting angle of the jackhammer. Not so when the cutting head is moving in two planes.

Like I said I definitely hold the minority opinion.
BTW thank you for such a gentlemanly rebuttal.

Greg, actually, the chisel, or spade-shaped cutter, can only move in one plane. It's a plane that lies across the two "spade" edges. It moves diagonally (up left or right or down left or right) but remains constrained on that plane. It's movement is created by two electromagnetic drivers on each upper corner of the cutter blade. It can cut a signal (wiggly undulations) into either groove wall while cutting a smooth groove wall (no signal) on the other side, Or it can cut signals, even different signals, into both sides of the groove at the same time.

I wish I could find a decent diagram somewhere to post. If not, I'll try and whip something up and post it.

cutting in one plane would dig a hole. to make a 45 degree grooved trench you have to move in two planes n'est pas? maybe I stated it wrong.

Greg, yes you simply stated it backwards. The cutter head stays in one plane but moves in two directions.

Imagine you have a nickel on your desk. Imagine that's the cutter head looking from the front. You put your finger on the nickel. You push it up and down, left and right. But it still remains in one plane -- the plane of the table.

I am thinking the cutter head acts more like a plow vibrating fom side to side. thus the record rotates under the cutting head as the head plows ahead vibrating either to the right or left, thus there is no downward cuttiing motion. that is why I prefer the vertical position.
I think I 've made enough empiracal arguments it's time to do some research.

Greg (and anybody else who seriously wants to know how this all works,) check out this page: YOU ASKED FOR IT !!

http://aardvarkmastering.com/westrex.htm

Note: until you get down to picture no. 9, you are only shown one coil, but pic. 9 and 10 clearly show both coils (at 45 deg. to the horizontal, 90 deg. to each other) each with a pin or "link" that is soldered to the torque tube. The cutter head or stylus is installed in pic. no. 11.

At the bottom of this page (I finally found one) is a line diagram of a Westrex cutting head:

http://aardvarkmastering.com/history.htm

Any questions?

i have a question, how can one adjust correct vta, without using microscopes and other equipment ? I use a Dyna. 17D on a JMW-9 tonearm, how would i be sure that the angle of the stylus is correct ?

Readster, basically, you're on the money or you're not. HOWEVER, it's perfectly valid to take the position that if you could get kinda, sorta, close to the money, you could live with that.

Here's how I'd go about doing that:

First, let me say that of a few different cartridges I've inspected (plus what I'm learning from folks who have taken the time to check using instruments) it appears that all cartridges with micro-ridge styli are built with SRAs in the following range:

At one end of the range, the stylus is vertical in the groove when the cartridge (top surface) is parallel to the record/platter. At the other end of the range, the SRA is around 1.5 deg. when the cartridge top surface is parallel to the platter.

In other words, if you got your cartridge parallel to the platter (which generally means your headshell and tonearm too) then you know this much: the SRA is somewhere between zero and 1.5 (+/-) degrees.

Let's say from this level position, you arbitrarily apply 1/2 degree more, or about 2 - 3 mm. at the tonearm post. So now you know that the SRA is somewhere between 0.5 degree and 2 degree (depending how much or little SRA was built into the cartridge initially) but of course you don't know which end of this range your particular stylus is at.

However you can tell by listening, IF you know what to listen for. Unfortunately, this kind of "informed listening" ability is most usually gained by my making SRA adjustments up and down from a correctly set SRA.

But basically it goes something like this (assuming everything else is set up correctly -- load, VTF, ASF, overhang, tangency, etc.):

Listen first to bass. Write down what you think you hear. Is there enough? If yes, how does it sound -- crisp with slam and attack or sort of rounded and/or muddy. If there's not enough or it sounds thin, then you have too much SRA. Reduce it until you have good clean bass without bloat. If it sounds bloated and muddy after you obtain good bass response, then you've gone too far, back off a bit.

Then (or if bass was OK to start with) listen to highs and midrange. If it sounds glarey or grainey or harsh in any way, it usually means (unless it's something else in your system) the you have too much SRA. Usually you won't have very good bass either, which confirms it's the SRA and not some component or cable. Reduce the SRA until the highs are silky. Still not enough bass, reduce the SRA a bit more, it won't affect the highs that much.

Were talking about tenths of a millimmeter here. So get yourself a set of automotive feeler gauges to help determine how much change you apply to the tonearm post (unless you have a TA that provides for easy adjustment of SRA/VTA)

Once you've got good tonal balance, see how you feel about image/soundstage. This is very cartridge/arm/TT dependent. But as anyone with a SRA-adjustable tonearm will tell you, there is one magic (SRA) spot with every record where the audio hologram just snaps into focus. It's very obvious and thrilling to hear.

thanks Nsgarch, for the great detailed explanation, that will help alot.

Nsgarsh,as usual,is correct regarding aural adjustments,and listening for bass.However I have found that though "the bass thing" is high on everyone's list,what really locks in the "now we're in the ballpark" area is extreme high frequency reproduction,played back at a good respectable level(NOT cracking plaster,though),and concentrating on tonal purity at these frequencies.Also,something like a triangle,being struck repeatedly,or better yet,some handbell music(A handbell choir will have a huge variety of fine inner detail,and hopefully superb naturally resonant inner textures at high frequencies).

What should be keyed on is trying to voice to the PUREST textures.This should come across as almost sweet,without the colorations normally associated with that word.

It's all too easy to "think" we have good bass,and this can leave a gap between fine sound and "spot on",which is the Grail, all of us seek.

A few LP's to consider(not that there aren't loads of others,but these are superb,though possibly hard to find)-----Ancient Airs and Dances of Hungary(Harmonia Mundi).---Music of Ancient Greece(Harmonia Mundi)--The Pealing Bells Of the Westminster Handbell Choir,this one is UNBELIEVEABLE,also can be found for about a buck(on the Omni-Sound label)---the soundtrack to the Bdwy play RASHOMON,another incredible disc,"worth it's weight in styli",and has some amazing and different/unique high freq instrumentation,with gorgeous different music(the Carlton label,which was pressed by U.S.Mercury)---Seventy Six Explosive Percussion Instruments,a direct disc on the Sonic Arts label.This is not what you may think,and has gorgeous subtle instrumental textures,as well as bang.------Russo's "Street Music",coupled with An Amer in Paris,on Deutch Grammaphone,killer sound with a harmonica that should seem to be played by Casper the Ghost,floating between your speakers.----EMI-Rachmaninoff's Vespers(pressed in USSR,but fabs),this has a TON of massed voices at almost constant crescendo level,and will immediately tell you if the arm/cart is dialed in correctly,or it will sound like steel wool.A killer disc(so good,you almost need nothing else).---Lastly---------The EMI boxed set of Penderecki orchestral music(I think three discs)containing the JAW DROPPING Harpsichord cto,which will knock anyone out of the "listening chair"!!----Oh,I forgot to mention "The Music of Franz Waxman",on the RCA label(prefferably English,but I have the U.S. pressing)Here is some great stuff,but the Piece d'la Resistance is "Bride of Frankenstein,Creation of the Female Monster" ,INCREDIBLE,FANTASTIC,STAGGERING,and actually lovely harmonic music.My pal Sid(the LP KING,for new discoveries)surprised me with this,some time ago,and just before Halloween.A real treasure!!High frequencies,and "LOWS" you NEVER KNEW YOU HAD.Guaranteed!!!

Let's face it--Analyzing equipment is great fun,but we do it for the MUSICAL PLEASURE,and great "FINDS",that seem to be available only on LP!!

Hope I didn't waste this post,with these,but they have proved invaluable(along with countless others)for helping to dial in my set-up,as well as some of my friends.The music,and sound are all "to die for",as well!

Best!!

Fascinating. This one's a keeper. Thank you Nsgarch!!

Dear Neil: I'm with you about: " Listen first to bass. ".

What happen in this frequency range has a high influence in the whole percieved sound , if it is bloated then we have a " darkness " that preclude natural/transparent sound but if it is muddy then the music foundation " is not there " and you know it. When the bass frequency range is spot on : the whole thing are spot on, at least this is my experience.

Sirspeedy: " It's all too easy to "think" we have good bass..."
Well, yes it is too easy: for the people that are not too experienced or to the people that are not in " touch " with the live music.
Your high frequency approach is a valid one too but I think is a little more " volatil " than the Neil one ( bass range ).

It is curious, I have a record that is one of my reference ( the top one ) LP for to know how near/far I'm from the " spot on " and in this record I'm not looking for any of both frequency extremes: I'm looking in the mid range. This record is one from Janis Ian ( Breaking Silence ): side 2 track 1: here it is ( at the middle ) a battery sound that when the drummer hit it you know when its right and when this recorded " battery moment " is " spot on " every thing is right, till now never fail.

Regards and enjoy the music.
Raul.

Raul,you are aware that the cutter angle always determines where the vta will be best.All lp's vary to some degree,but I don't like to adjust to each record.I know this is not new to you.So no need to respond.Also,I use a number of lp's to make my "averaging".Also if one sets to what we hear as high freq "PURITY",over a wide range of tough to track lp's,you will be in the "perfect" zone!!BTW--If you like the wonderful "Breaking Wind",oops,just kidding,I meant "Breaking Silence",You will LOVE the Ricky Lee Jones LP,called "POP,POP"!!Out of print,but worth seeking out.

Best!

Dear Sirspeedy: " but I don't like to adjust to each record. ". I'm not either.

" Also,I use a number of lp's to make my "averaging". ". I also do the same.

Well, I like Ricky Lee Jones, as a fact a like the Music almost any kind but heavy metal ( I own some heavy netal LPs???? !! )

Regards and enjoy the music.
Raul.

Sorry Raul,Heavy metal is NOT in my collection.Almost everything else is.I would never have guessed you like Heavy Metal!!!!!!Never thought you were a heavy metal guy!!!!

Actually,other than my normal Classical,Jazz,and Avante Garde Classical,and Popular stuff,I have REALLY been going crazy over the earlier LP's of Perez Prado,and Tito Puente!!I haven't heard any newer groups that can duplicate their way with arrangements.Also,if you have heard them,originally,on vinyl,with their "original" musicians,it is hard to listen to the modern versions of this GREAT music.I just can't get used to anything electric,in great Latin music,though I had always loved Santana.Yet now that I have heard these guys,I think TITO well deserved the Royalties that he WAS payed,by Santana,for his arrangements.GREAT STUFF,those originals!!

Best!

Dear Sirspeedy: Yes those original Perez Prado/Tito Puente and the like latin music were great and today we can´t find nothing nearest. Like you, I love Santana too.

I think that not only in this music genre but in classical, jazz, pop, blues, rock, etc, etc, we are in decadence from many years to now: the great composers and interpreters all dissapears: are " things " of the past.
There is nothing growing up about: where are the Bethovens/Stravinskys,Mhalers, Beatles, Fitzgeralds, Miles, Evans, Peres Prados, Jobim, Caruso, Callas, Streisands, Presleys and the like ?. The new generations about are on a lesser/different level and maybe I don't understand exactly their " music " flavor.

Regards and enjoy the music.
Raul.

Raul,you may want to experience "some" of John Zorn's work.Available mostly on CD.The film series is where I'd start,and is magnificent music.The Tzadik label(he owns)is of very high quality!Also,if you follow some music publications,like Grammophone,etc,you can choose some of the "well reviewed" music,and download samples at some of the better "book/music" stores.This way it becomes clear that there are still talented composers out there.The problem is,that we are not exposed enough,to them.Profits drive the music business,so we have to do the work,ourselves.I have NO problem looking,hard,for NEW music,and it is real fun,when I make a new discovery.

Best!

BTW,Raul--I hope you were not too influenced by your taste for Heavy Metal,when you "waxed poetic" about all the subtle virtues of the ALLAERTS stuff.Somehow the harmonic,and timbrel virtues of something like a softly played oboe,or viola,would seem to be more in line,with what Jan is trying to communicate,than anything by Axel Rose!Not that it isn't fun to "rock out",but you get my point!

Dear Sirspeedy: I think that the best orchestra music it is making on the film soundtracks: Zimmer, Horner, Williams, Newton Howard, Kloser, Vangelis, etc.

All these recordings are almost only on CD. Many of them are great compositions.

Regards and enjoy the music.
Raul.

Dear Sirspeedy: Now that you mentioned there are very good compositions on the film soundtrack kind.
Zimmer, Horner, Williams, Newton Howard, Kloser, etc, etc, are very good ones.
Unfortunatelly almost all these kind of recordings were only in digital format, well not unfortunatelly: fortunatelly exist ! ! !.

Regards and enjoy the music.
Raul.

Raul,try to find some of the RCA "Classic Film Series" LP's.These are easily obtained,and not alot of money.There is fabulous music contained in the entire series,which is quite a few discs.GREAT STUFF,in gorgeous sound.These were pressed in both Great Britain(prefferable),and the U.S.(not quite as good as the British pressings,but fine,nevertheless)!!

Also,for some really fun stuff,in very good sound(for digital LP's),there is a series called "The Twilight Zone"!I believe there were four LP's released.I have the first two volumes.Wonderful composers,from Franz Waxman,to everyone popular in the fifties and sixties.Though the discs came out around 1981-1982.Plenty of Bernard Herman compositions were on the sound track as well.A real FIND if you search it out.Guaranteed to keep you from falling asleep,if you have become familiar with some of the TV series!!

All this stuff,will definitely provide superb fuel for the fine cartridges you love to write about.These discs contain beautiful music,wide "dramatic" dynamics,and superb timbres with lovely,subtle inner voicings that really seperate the finest of cartridges from oneanother.

Another GREAT LP,but scarce,is the soundtrack to the Bdwy play "Rashomon".On the Carlton label.Sonically this disc blows away the Twilight Zone discs,and they are not bad,at all.Recorded and pressed by U.S.Mercury,so I don't have to tell you how great the sound is.The music is INCREDIBLE,and will show off the "best",in a great cartridge,and system.Believe me,if you want to know how good your set-up is,this disc will tell you!Guaranteed!!

Worth seeking these discs out!

Best!

Wow, this thread is really full of important information. Related to this topic, I have recently heard of a “theory” from my friend that I have never heard before, and I am kind of skeptical about it. So, I think this is the place to find out the answer. Since I am a bit confused, please bear with me. His “theory” goes like this:

1, Due to the different cutting angles used by different labels (and the cutting lathe they used), Decca, EMI, etc., you will need different SRA/VTA to play the different labels of LP.

2, Different cartridge makers manufacture their cartridges with different build-in VTA (he said something like 20 degrees and 22 degrees). As such, to have a perfect playback, you need to match the cartridge (with it’s build-in VTA) to the record labels. For example, say an Ortofon, with 20 degrees build-in VTA, will fit the Decca, and another brand of cartridge, say a Clearaudio, with 22 degrees of build-in VTA, will fit the EMI etc.

3, As such, you’ll need at least 2 cartridges to ideally/accurately playback the different labels.

I am very skeptical of this “theory”, and I think this forum is the perfect place to ask whether there is any truth to it.

Thank in advance

Michael

A wrong theory carried to a ridiculous extreme.

Actually, it's a right theory carried to a ridiculous extreme.

A simpler solution is a tonearm with adjustable height. Then you can use any cartridge you like and play any record you like, while matching SRA.

A simpler solution is a tonearm with adjustable height. Then you can use any cartridge you like and play any record you like, while matching SRA

Yes -- but by adjusting height you'll be changing the stylus overhang. As you note, having two arms is the right way -- but an extremist solution!

I am still looking for an article or picture that demonstrates that angled cutting head produces an angled cut. Has the angled groove been measured? All I have ever read is that it was just assumed.

Dear Doug, Gregm,

Base on what I understand from your answers, it is the SRA that is important, not the VTA (of course, the SRA and VTA are interrelated). As long as you can adjust the SRA to fit the angle of the cutting heads, it would be ok. So, any cartridge (no matter whether it has a build-in VTA of 20 degrees or 22 degrees) can be adjusted to fit any cutting angle. Am I correct?

Now, my friend’s “theory” actual goes one step further, which I have hinted but didn’t really state out clearly in my original question. It goes like this:

Going back to my original example “say an Ortofon, with 20 degrees build-in VTA, will fit the Decca, and another brand of cartridge, say a Clearaudio, with 22 degrees of build-in VTA, will fit the EMI etc.”, his theory is that with a Decca LP, an Ortofon (due to the fit of it’s build in VTA) will always sounds better than a Clearaudio no matter how you adjust the arm/cartridge (even if you adjust the SRA/VTA for individual records), assuming the cartridges are in a similar price range. And vice versa, an EMI LP will always sound better with a Clearaudio. So, if you want to ideally play back all the LPs, you will need one cartridge with a 20 degrees build-in VTA, and another one with 22 degrees build-in VTA.

Well, based on the answers I got from you guys, I guess this theory is false.

Thanks again,

Michael

SRA is very easy to match to the cutter head rake angle. True, there is/was no absolute standard, but the range of variation is very small, and so even if you don't have a tonearm with on-the-fly adjustable arm height, you can usually find a happy setting that fits most record grooves at least 90% perfectly if not 100% all the time. The trick once again is to find the absolute vertical point described at the beginning of this thread and then go from there.

VTA is another matter altogether. It is the angle of travel described by the cutter head as it moves up and down and depends on the design of cutter's torque tube (something like a cartridge cantilever.) There is some variation here also, but the big (and impossible to match) variation is among cartridges themselves. Cantilever length is all over the place among different cartridges, so it always struck me as folly to even attempt to match cutter VTA. A mismatch wil only create forth order harmonic distortion (if I remember my reading correctly) which is virtually inaudible, and so any attempt to "dial in" VTA by ear would be futile anyway. That's why I get upset when I hear the term "VTA adjustment" in any context. Call it whatever, but what's really going on is SRA adjustment.

Greg, adjusting arm height (in the range we're talking about here) has no effect on stylus overhang. That's function of the position of the tonearm base relative to the platter spindle -- with fine adjustment available via slotted headshell mounting holes, or in the case of SME, a sliding tonearm base.

Well, based on the answers I got from you guys, I guess this theory is false.

That's wasn't my answer or Nsgarch's. I said the theory was true but that attempting to apply it would be ridiculous. Nsgarch elaborated by explaining why matching VTA between individual cutting lathes and cartridges would require too many cartridges and would be virtually inaudible anyway.

Gregadd,
Put a stick of soft butter flat on a plate.
Hold a sharp, pointed knife straight vertical, with the edges of the blade oriented across the stick.
Lower the point into the butter and drag it the length of the stick, moving it left and right as you go.

Now rotate the butter to put a fresh side on top.
Hold the knife edges across the stick as before, but angle the point sharply either point-forward or point-back.
Cut a modulated groove as before.

Compare the two grooves. They are clearly different. The modulations cut with the vertical knife have straight vertical sides. The modulations cut with the angled knife have angled sides. The only way to accurately re-trace either groove is to use a blade with the same size and shape and hold it at the same angle (SRA). Any other angle will cause the blade to slur past parts of each modulation, creating playback timing errors.

We adjust arm height for each LP. The changes we hear are consistent with SRA-matching theory. Some people do not hear the differences as readily as others. That's normal, but it doesn't change the shape of the butter!

Doug- given that stylus rake angle is such a well accepted theory somebody must have done this already. With far more accuracy than I can. From what I have gathered so far the head is more like a plow than a knife. It cuts forward and to the side. The cutting head digs down into the vinyl cutting ahead and side to side. The master is rotating underneath the head.
To further complicate matters the cutting is now being heated. This means that there is some melting going on. The articles all swear by SRA again providing no proof.

Greg, maybe you (or Doug or I) can find some microscopic groove photos that will show this rake or slant in the groove undulations clearly. I know Last used to show such photos with their products. I'll see what I can find.

Neil

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