[tomytoons]

Damn, Wayne
That "nifty little box" you got there is cool. You should  sell that.
I like it.

D

[Ericus Rex]

Yes, tracking force must be applied to set correct SRA. The point I was really trying to make is that "correct" SRA of 92 degrees is not always with the cartridge top parallel to the record surface. As Michael Fremer's pics on the analog planet show, many cartridges are not parallel and some differ quite a bit from samples of the same model.  One should always listen and/or measure. (if you have a usb microscope) I doubt that anyone can say just where the correct SRA will be given the apparent variations. So we all have to listen and/or measure and trust our ears.

I imagine there are manufacturing variations in suspension stiffness that would affect the SRA at a given tracking force.  I.E. using the body of the cart might not always be the best reference for canitlever/stylus angle.  I'm with Neobop on this one; don't stress out about the exact angle.  Just use your ears and enjoy the music.

[Russell Dawkins]

"90º" - "92º" - how in blazes can you visually determine the angle of the stylus tip in the groove to an accuracy of anything closer than ±2º or so?
Surely you must be guessing to some extent. Do you think auto-suggestion may come into play at some point in the process?

Are the angles cut by the cutting lathe always the same? Do you need to optimize the playback angle for different cutting standards? If so, you'll need to be able to adjust quickly over at least a 5º arc depending on whether you are playing European, British or American made recordings, and what year they were made:
http://www.hi-fiworld.co.uk/vinyl-lp/37-technology/73-vertical-tracking-angle.html

Furthermore, ideally the playback stylus should duplicate the movement of the cutting stylus and that includes the vertical component of the motion which is required by stereo (it is the "S" component) - and that brings the distance of the stylus tip from its pivot point into play, because as the stylus moves up and down its angle with the surface is constantly changing because it is pivoting. The only way for the replay stylus to duplicate these angles would be for the pivot distance to be the same as the cutting stylus.

The best solution to me is one that is too-infrequently implemented by turntable manufacturers - easy, on-the-fly, VTA adjustment - and adjusting by ear, disc by disc.

[Wayner]

Hard-cores are using a USB microscope, taking a picture, copying it and doing some drafting on it to measure the as is condition. Then they adjust according to which direction they need to go.

I have a camera that can zoom in very close, and used with a reading magnifier, can get the same results. You can guess, I guess, but then that kind of goes against the whole point of the thread, I guess.....






 

[jimdgoulding]

Think Rex is probably right.  In the end, it probably comes down to what tonearm, age of suspension, and other things.  At the moment, my Rega tonearm's bottom side is precisely parallel with the record surface and the cartridge body is half a hair lower, or very slightly, at back.  I know that doesn't sound right, but that is the way it looks.  The stylus tip appears to be at a 90 or 91 degree angle to the record surface.  When playing I imagine that changes a bit what with stylus drag.  My tracking weight is 1.5 grams, BTW.

I dunno what to make of the magnified stylus tip cut photo published by BaMorin earlier.  If what he says is accurate then I must be in the 92 degree neighborhood.  However, if Wayner's illustration is more accurate, I'm too low.  I'm gonna talk with the fellas at Grado next week, Ba.  I'd also like to talk to some recording engineers like Keith Johnson, for example, and will try.  I don't put much credence in what MF has to say.  Some, of course, but who annointed him Guru.  And is everything cut at 92 degrees?  Since when, if so.  Imaging is currently restored and the midrange seems more balanced.  Previously, tho, with the tonearm lower at the back of the arm, my midrange was just so palpable and pure I thought I had died and gone to heaven, even tho there was a loss to soundstaging, one of the things my system does well, and this is the reason I am continuing to raise (or lower) the arm a half a hair at a time.     

Good photo, Wayner.  I can't quite see as expertly with my 15X magnifying glass but pretty close, which should answer your question, Russell, and, yes, in the end you're very right, IMHO.

[Russell Dawkins]

I have a camera that can zoom in very close, and used with a reading magnifier, can get the same results. You can guess, I guess, but then that kind of goes against the whole point of the thread, I guess.....

So, are you saying this looks like 92º to you? It looks to me more like 96º if I had to guess, or 6º off the vertical.

Unless I'm miss-interpreting the information in my link above, the cutting angle is standardized around 15º-20º. From the "Standards" paragraph:

"It would appear that the cutting world is now achieving an effective modulation slant on disc of around 15° in the United States and 18° in Europe and that for minimum distortion we should therefore be aiming for these figures in pickup cartridge vertical tracking angle. As you might have guessed, the point I am about to make is that in spite of adequate passage of time too many cartridges do not appear to approach this ideal."

[jimdgoulding]

Think I'll give Reference Recordings' 45rpm "Dafos" a spin tonite.  Wish you were here.  Think I agree with you, Russell, bout the photo.  Maybe, Wayner, you're overdoing it?  Where did you get that illustration on page one?  Thanks.

[Wayner]

Perhaps you gentlemen forget that I'm an engineer, and the stylus shown is indeed at 92°. Not 93 or 96. I have carefully measured it and it is at the angle I want it to be. I'm not going to spend further time illustrating even more stuff on this, but rest assured, I am more fussy about this shit that most of you...I do after all, have the obsessive/compulsive disorder. That simply means that I do not rest until all is correct.

If you watch the Big Band Theory, I would be Sheldon. (but not gay).

Wayner

[jimdgoulding]

Wayner, your opinion, your research, is well regarded in these parts, you bet yer dang skippy.  So, for dummies like me, what BaMorin says about when the cartridge body is parallel to the phono record at rest, the stylus cut would then equate to 92 degrees tracking in use is incorrect.  If I misstated Ba, please clarify.  Thanks.  I'd still like to know where that illustration came from.  Is that something you created?  Thanks, again.

[neobop]

So, are you saying this looks like 92º to you? It looks to me more like 96º if I had to guess, or 6º off the vertical.

Unless I'm miss-interpreting the information in my link above, the cutting angle is standardized around 15º-20º. From the "Standards" paragraph:

"It would appear that the cutting world is now achieving an effective modulation slant on disc of around 15° in the United States and 18° in Europe and that for minimum distortion we should therefore be aiming for these figures in pickup cartridge vertical tracking angle. As you might have guessed, the point I am about to make is that in spite of adequate passage of time too many cartridges do not appear to approach this ideal."

I've seen other photos of Wayners' that look perfect with perpendicular reference lines. Some USB scopes have a vertical line or target which would make it easier, provided it's 90 degrees from the cantilever.  A photo like that or series of photos, taken perpendicular to stylus could be analyzed with a protractor. 

Since that article was written, cutterhead VTA was standardized.  See the link to the Asylum article on page 1 of this thread.  92 will give you correct SRA for virtually all modern records of similar thickness, which brings up another aspect. 

If you look at the record surface, arm pillar, and arm tube to stylus as three sides of a right triangle, it's easier to visualize implications of changing 1 aspect of this triangle.  If you change the height you'll also change the hypotenuse (arm tube eff length) and change horiz alignment.  A thicker record will effectively lower the arm.
All is not lost. A small change in height won't do much to horiz alignment and could nail vert alignment.  But a large change in height (> 2, 3 mm) will.  If you set and forget, 92 vert is where you should align.  This is also true for height changers. It helps to have some kind of marking to return to 92.  Risch says 91, because error on the low side tends to sound less strident.

For those who doubt the validity of, or can't hear SRA changes, IMD can be measured with test equipment.  All you need is the right test record with an IEC IMD test track, and an IMD tester.  I did a quick search for an IMD tester and saw a nice looking one for $8K. Maybe there's a PC version for much less.  This test signal is 60Hz and 4KHz 4:1 ratio.  What the analyzer does is sum the signals then subtract the originals. What's left is intermodulation distortion. Perform this test at diff arm heights for correct vert alignment.

You can't just change arm height to correct 4 or 5 degrees of SRA, not w/o messing up alignment.  A 9" arm requires 4mm height adj for 1 degree correction. A longer arm requires more.  I have some old records from the '50s and '60s. I'm not sure why, but it usually doesn't take more than a few mm adj at most, for them to sound "right".  I read of someone who uses 2 mats, a regular and a ring mat. For thick records he just removes the ring mat.  You can train your ear to hear correct SRA.  I don't think a vocal is the best choice for this.
neo

[jimdgoulding]

Good post, Neo.

[ArthurDent]

Great thread Jim, lots of good info. Keep it coming guys.......

[trackball02]

Wayner,
I have a Grado Reference Master, and here is my attempt to replicate what you showed.
I took the photo as it is resting on a CD. I'm using a stock Harman Kardon T60.
Any comments would be appreciated.
Thanks,
Jay

[jimdgoulding]

Hi, Trackball.  My cantilever looks like that but my stylus does not if your pic was shot at a straight 45 degree angle.  My Sig Ref cart is an eight year old or so model thereabouts.

[trackball02]

jimdgoulding,

I just tried another angle, so that is is 90 degrees to the long axis of the cartridge. Is this better?

I'm really pushing the limits of resolution of my handheld point and shoot camera. I going to try to find a better camera.

[andyr]

Wayner,
I have a Grado Reference Master, and here is my attempt to replicate what you showed.
I took the photo as it is resting on a CD. I'm using a stock Harman Kardon T60.
Any comments would be appreciated.
Thanks,
Jay

Hi Jay,

Was your headshell horizontal, when you took that pic?

Thanks,

Andy

[jimdgoulding]

TB-  Your picture is marvelous, no worries.  Yep, my Sig Ref Grado does not have those same angles.   Good idea bout shooting on a CD for resolution.

[trackball02]

I'm trying to figure out the best angle to point the camera. Should the plane of the image be parallel to the top of the CD, bottom of the cartridge or top of the headshell? I think the headshell is horizontal to the top of the platter. I just tried to aim between the planes of the CD and bottom of the cartridge.

Do you think it is close to the optimal 92 degrees?

[jimdgoulding]

I'm trying to figure out the best angle to point the camera. Should the plane of the image be parallel to the top of the CD, bottom of the cartridge or top of the headshell? I think the headshell is horizontal to the top of the platter. I just tried to aim between the planes of the CD and bottom of the cartridge.

Do you think it is close to the optimal 92 degrees?

Wayner is probably the best cat to answer that.  I'm still tryin to get optimal on my own.  Optimal sounding.

[neobop]

It is extremely difficult to get an accurate photo for SRA evaluation.  What you're looking at is deceiving, mostly due to parallax error.  The center of the lens must be squared up with the stylus, in height and side to side angles, plus the side of the cart must be exactly perpendicular to the lens. This is impossible with a hand held camera, especially one that doesn't have through the lens viewing. You're not even seeing the same image as the lens, and a wide angle lens probably isn't the best choice either.  I'm sure we've all seen photos where a straight side of a door or building looks like it's on an angle. Looks can be deceiving.
neo