Cart/ Stylus Terminology question.

[Fishead]

@Thomas_AA, where did you get that collection of shims? From Wally Tools?

 

[Thomas_AA]

@Thomas_AA, where did you get that collection of shims? From Wally Tools?

No, I designed them and had a friend print them.

 

[Thomas_AA]

@Thomas_AA , good posts!
I am wondering if a listening test with different shims/VTA may be useful. We know that correct VTA lowers all kinds of distortion significantly and can improve crosstalk too, and that the frequency responses hardly changes. So what are folks hearing ? Is it the change in distortion when they subjectively report tonal changes? Or is tail up/down just hearsay and a myth? Or what?

Thanks!

One problem with measuring frequency response left/right is that it may not always be representative. We know that crosstalk gets higher with frequency, and that VTA affects crosstalk. So it is possible that VTA, affecting crosstalk, change levels and/or channel balance in the 10-20 kHz range. A second point is that VMA (cutting angle) is not fixed at all frequencies. But any change would be quite small.

 

[Hajidub]

Thanks!

One problem with measuring frequency response left/right is that it may not always be representative. We know that crosstalk gets higher with frequency, and that VTA affects crosstalk. So it is possible that VTA, affecting crosstalk, change levels and/or channel balance in the 10-20 kHz range. A second point is that VMA (cutting angle) is not fixed at all frequencies. But any change would be quite small.

Antiskate could play a role in channel imbalance. Riding one side of the groove or the other will definitely make a difference. In drastic cases you can view the stylus from the front of the cartridge and see the cantilever skew to one side or the other. Overall the preferred method would be a test record, which I've never owned after 40 yrs of this silly game.

 

[mr_petit]

I am wondering if a listening test with different shims/VTA may be useful.

It would be very useful. Not only to see what kinds of effects will be audible in what way, but also in the scope of amount of vta change.
With that last thing I mean that if you make shims that give 2deg differences, that might not be very applicable to real life as most tonearms only offer about +/-1,5deg of vta correction (raising or lowering the arm base by +/-6mm).
Any cartridge that needs more VTA correction than that a normal tonearm can correct I consider a manufacture defect/a dud and should be returned for a new one.

It would be interesting to see if the more popular cartridges (like for example at-vm95ml or at-vm740xml or similar) which are considered excellent trackers fit within that +/-1,5deg tolerance if such small vta angle corrections are audible (or even measureable...do you know if that's the case?)

 

[mr_petit]

Antiskate could play a role in channel imbalance. Riding one side of the groove or the other will definitely make a difference. In drastic cases you can view the stylus from the front of the cartridge and see the cantilever skew to one side or the other. Overall the preferred method would be a test record, which I've never owned after 40 yrs of this silly game.

In my experience, for imbalance due to antiskating becomes audible, you have to be off by quite a large amount.
The experience I did was to take a mono 45rpm pop record with quite strong signal (so lots of skating force to be corrected), and determine the right amount of antiskate needed for that particular song with my orsonic side force checker (so that I knew what the correct setting was, so for example say I needed to set the AS dial on 2.0 on my dual 721), and record that mono song with different antiskating levels (like 1.0, 1.25, 1.5 etc etc on that dial).
Then invert 1 of the channels and combine it with the other channel (so a null test) and hear when the resulting signal actually became stronger.
And on my scale you had to be off by 0,5. So for that specific turntable that say the exact/correct amount would be 2.0 on the dial, I had to lower it to 1,5 (or raise it to 2.5) for me to say that it would be audible in the null test. If that is then audible in real life is another thing, as the null test sound is very quiet (like -30dB or something like that if I were to guesstimate), so it is somewhat doubtful if you could hear that in actual music in an abx test.
I think I could look up how much the actual deviation in mg (or % from VTF) was, but of course it's quite a lot if you have to lower it from 2.0 to 1.5 on the dial.

I used music and not a test tone because it immediately became clear that the differences were made on the sibilants and similar notes, so the difficult to track/trace aspects of music, and test tones are not really suitable for that, unless someone has +##dB 10khz tracks etc.

That difference when it became audible in the null test was (coincidently) also roughly the same scope of various amount of required antiskating for different popular music styles/era's
So for example records that are cut really hot (mostly 80's dmm pop, for instance a record from tears for fears or michael jackson or whatever) require 2.0 on that specific dial (with a specific VTF), whereas a typical 70's soft rock song (say a song from paul simon) required 1.5 on that AS dial, and a typical modern pop record (say the Weeknd or Daft punk or bruno mars or whatever) typically requires 1,75 on that dial. This is all measured/set on the loudest part of the chorus, generally the loudest part of a song and due to the nature of how wrongly set AS becomes audible in the nulltest, also the most normative part of the music signal (when it comes to audible differences).
For differences in uneven wear, it might be a different matter, but that is something that is very difficult to measure.

I might have those music files still somewhere, although everyone can do this test for himself, if you have a mono record that is.

 

[doctor fuse]

Question: is there more (or less?) stylus and record wear if the SRA is off from the angle the record was cut at, than if it was 'perfectly' the same?

 

[multirock]

To my ears, there are clear differences in sound when you modify VTA/SRA. Specially in the bass frequencies. Bass can sound dry and compress if you tail up to much your arm pivot, or it can sound floopy and undefined if you tail down too much.

 

[jqp]

It is likely that most of us have the tools necessary to adjust SRA and azimuth. A compact disc, magnifying device and good lighting. When viewed from the front, the stylus and it's reflection should form an hourglass shape. Same goes for the SRA if using a conical or elliptical stylus when viewed from the side.

Azimuth is pretty easy to adjust if using a bayonet SME type mount headshell on a J or S shaped tonearm. There is usually a little bit of wiggle room on the rotational axis. Rotate the headshell until the hour glass shape is good and then lock down the collar. This adjustment works best with a cheap headshell as there is more "slop".

Pictures are from a Magnavox Imperial TT pulled from a console. Just what happens to be in my downstairs rig today. Rake angle is past 90 degrees at 2.5 grams tracking force. At 1.5 grams it is at 90 degrees.

 

[Thomas_AA]

It is likely that most of us have the tools necessary to adjust SRA and azimuth. A compact disc, magnifying device and good lighting. When viewed from the front, the stylus and it's reflection should form an hourglass shape. Same goes for the SRA if using a conical or elliptical stylus when viewed from the side.

Azimuth is pretty easy to adjust if using a bayonet SME type mount headshell on a J or S shaped tonearm. There is usually a little bit of wiggle room on the rotational axis. Rotate the headshell until the hour glass shape is good and then lock down the collar. This adjustment works best with a cheap headshell as there is more "slop".

Pictures are from a Magnavox Imperial TT pulled from a console. Just what happens to be in my downstairs rig today. Rake angle is past 90 degrees at 2.5 grams tracking force. At 1.5 grams it is at 90 degrees.


View attachment 3830772
View attachment 3830773

What you don¨t see is the alignment of the coils/magnets to the groove walls. Needs measurement using crosstalk.

 

[Thomas_AA]

Antiskate could play a role in channel imbalance. Riding one side of the groove or the other will definitely make a difference. In drastic cases you can view the stylus from the front of the cartridge and see the cantilever skew to one side or the other. Overall the preferred method would be a test record, which I've never owned after 40 yrs of this silly game.

It's small. Channel imbalance is often cantilever being off, and while it can be off with wrong antiskate, this is usually small effects.