The importance of VTA, SRA and Azimuth - pics

[bblue]

This is not an issue at all. I tried to keep my post as simple as possible, but in that case, all you have to do is compensate for this in the final calculation:

1. You start again with a perfectly parallel arm, and constant VTF
2. You lower the arm by X units to get a vertical stylus
3. Using the same trigonometry formula, side 'b' and now side a'=X (a' sits now below 'b'), you calculate the "negative" angle of "error" (i.e. the angle that's formed now below side 'b'), A'. Don't forget that now side 'b' has lengthened a bit and VTF has increased, so A' is yet again another approximation, but still very accurate
4. You return the arm to the parallel position and then you base your subsequent calculations on a desired SRA angle of A-A' - so if you want a final SRA ~= 2 degrees, you base your calculations on 2-A'. Done.

In fact, exactly because of what you said about the A90 is true and was my experience as well, I did NOT adjust VTF (not that it's easy with the VPI arm either), so I left it at 2.3g and used the approach above instead. If you go back to the A90 thread's post #67, take a look at the second picture's legend: it says "New vertical (-4mm from original)" - the 'old' vertical (incorrect as subsequently proven with the microscope and magnification) is with the arm perfectly parallel, the 'new' vertical is by lowering the arm by 4mm.

In the end, it's really simple trigonometry that yields very good approximations because of the caveats mentioned before (side 'b' and VTF being affected during the process). I found empirically that the best sound was within +-0.5mm of arm adjustment from the calculated value, and we are splitting hairs at that point...

Therefore, this approach offers a predictable mapping of desired SRA and arm adjustment, and does not pontificate that 2 degrees SRA is really ideal. The real trick is in getting a good reference point: a vertical stylus within the recommended tracking range; and, in my view, getting the final SRA still within the recommended VTF.

So this is how I got the A90 to actually track within the recommended range...

Ok, I'll give this approach a try next time. Thanks for taking the time to explain it.

One note though, you mention above lowering the arm to get the correct perpendicularity, when in fact on the A90's (mine anyway) you have to raise it to get the same results at 2.3g as you would without raising it and tracking lighter.

--Bill

 

[ack]

Ok, I'll give this approach a try next time. Thanks for taking the time to explain it.

One note though, you mention above lowering the arm to get the correct perpendicularity, when in fact on the A90's (mine anyway) you have to raise it to get the same results at 2.3g as you would without raising it and tracking lighter.

--Bill

Yes, mine was obviously different (this is really yet another reason why a microscope is necessary) - but you get the idea. So in your case, desired SRA will be A+A'. Given this, I would then start with a higher fixed VTF, perhaps 2.4g, in order to end up still within the range.

 

[ack]

Apparently this thread is getting international attention, so at the risk of excessive boasting - but really only to add more data points for everyone interested - I wanted to point all readers towards Fremer's Analog Corner in the May 2012 issue of Stereophile, where he admits misjudging the Lyra Titan i's high frequency performance because of incorrect SRA adjustment due to the lack of a USB microscope 10+ years ago; basically, he admits that solely adjusting by ear wasn't good enough for him.

The point here is, once more, that if you are serious obvious about cartridge set-up get such a microscope and spend the time to get an extremely accurate reference, then adjust by ear. One of the major underlying problems that necessitate this is that stylus mounting on the cantilever is all over the place, even for pricey cartridges, as you will see in his write-up, with significant variations in angle relationships.

In the end, when a manufacturer claims that a certain VTF will achieve optimal VTA (with an equivalent optimal SRA) they are simply over-simplifying things for the layman. Fremer's article is a must-read.

 

[jazdoc]

Ack,

Thanks for bringing up Fremer's article. It was very well written and I was impressed with his public acknowledgement that he was wrong with respect to his Lyra Titan assessment. It's hard for an expert to admit a mistake and to do so demonstrated character. That he went through the process of explaining how he went wrong and what he learned only added to the article's value.

One of my take aways from the article was why he was unable to optimize the Titan during his initial review. He had VTA set up with the tail of the armwand below the horizon but didn't keep going because he assumed that the tail of the arm shouldn't go further down...

Why do I mention this? IME, a proper cartridge set up will require finding the right VTA/VTF/azimuth at least twice. When you think you've got things dialed in, the only way to confirm this is to keep going until the sound gets worse. Using VTA (and by proxy SRA) as an example, if the sound improves as you raise VTA, you have to continue raising VTA until it sounds worse. Then you have to drop VTA back down to optimal. If you want to start by using the USB microscope to get SRA at 92 degrees, you still need to confirm by ear by varying VTA/SRA around the 92 degree SRA setting. I suspect many high-end analog rigs don't perform at their best because the set up is not dialed-in. IME, last little improvement in set-up yields huge sonic benefits. Unfortunately, this requires patience, practice and oft times the assistance of a fellow audiophile with 'good ears'. It may require several sessions over several days to get things spot on.

I'll be interested in getting others input...

 

[ack]

Quite correct sir. Another important take-away from Fremer's article, kinda hidden though you did touch on it, is that adjusting VTA/SRA eventually also affects azimuth, because of how the headshell is offset at an angle from the armwand (simple geometry again) - I found mine way off after SRA adjustment, and this was the final adjustment I made. I also suspect a lot of sub-optimal set-ups due to incorrect SRA and azimuth.

BTW, thanks to our friend jadis and others who will/have exposed this thread to a wider audience.

 

[jazdoc]

Quite correct sir. Another important take-away from Fremer's article, kinda hidden though you did touch on it, is that adjusting VTA/SRA eventually also affects azimuth, because of how the headshell is offset at an angle from the armwand (simple geometry again) - I found mine way off after SRA adjustment, and this was the final adjustment I made. I also suspect a lot of sub-optimal set-ups due to incorrect SRA and azimuth.

Excellent point. An excellent technique to adjust azimuth is found on the Durand Tonearms website:
http://durand-tonearms.com/Support/Support/azimuth.html

The end of the discussion closes with a general observation regarding tonearm/cartridge set up that is worth quoting:

As with any fine adjustment, it takes time and patience to get it right. It's the same thing with tracking force and VTA/SRA adjustments: you can do it by eye, or follow the manufacturer's recommended setting, and hope for the best. Or you can experiment, try other settings just to see what happens, and suddenly discover uncharted territories. Through practice, your ears will get better at hearing the fine differences, and this in turn will take you to new heights of musical enjoyment.
Nobody said playing vinyl was instant gratification...

Just as a performer needs to understand how to take advantage of his fine instrument, anyone who has engaged for a significant period of time with the setup of a sophisticated tonearm knows that it can take a very long time to understand how it reacts to minute variations and how to anticipate its reactions and play with them. The more you play with it, the more you realize what it can do and how to make it sound its best, and the more it gives you back. And when you get it right, you can sit back and enjoy the new level you've just reached in your analog experience!

 

[andromedaaudio]

I do it all by ear /eye , the cart i use at the moment has the needle mounted (almost) 90 degrees to the record surface .
If i am not satisfied with the sound or if i have mounted a new cart , i play with arm height and needle weight (and anti skate) on familiar records untill i am satisfied , this does mean exeeding advised factory settings and finding the limits of the cart .
I mount the cart in the headshell and align it be eye , Tracking force and armheight can make or brake a carts performance and its what analogue is all about .
The better executed /more solid / stable design turntable/ arm the more easy /precise the proces is

 

[jadis]

Quite correct sir. Another important take-away from Fremer's article, kinda hidden though you did touch on it, is that adjusting VTA/SRA eventually also affects azimuth, because of how the headshell is offset at an angle from the armwand (simple geometry again) - I found mine way off after SRA adjustment, and this was the final adjustment I made. I also suspect a lot of sub-optimal set-ups due to incorrect SRA and azimuth.

BTW, thanks to our friend jadis and others who will/have exposed this thread to a wider audience.

And thank you too, ack, for your kind permission to post the pictures here on our local Philippine audio forum.

My interest on the subject of proper SRA, VTA, azimuth adjustment was perked up when a close friend who just bought a Lyra Atlas communicated with MF on its optimum adjustment and MF sent him digital microscope pictures to demonstrate SRA adjustments. In fact, MF recommended my friend to buy a digital microscope for best results.

 

[bblue]

Quite correct sir. Another important take-away from Fremer's article, kinda hidden though you did touch on it, is that adjusting VTA/SRA eventually also affects azimuth, because of how the headshell is offset at an angle from the armwand (simple geometry again) - I found mine way off after SRA adjustment, and this was the final adjustment I made. I also suspect a lot of sub-optimal set-ups due to incorrect SRA and azimuth.

BTW, thanks to our friend jadis and others who will/have exposed this thread to a wider audience.

Actually VTA/VTF/SRA adjustments don't directly affect azimuth. They actually affect overhang, which affects azimuth. The correct next counter-adjustment after SRA would be overhang, which when set correctly will bring azimuth into correctness.

--Bill

 

[ack]

Thanks for the clarification Bill. BTW, I just edited my key post #52 above with clarifications, marked as [edit: XXX] in italics

 

[bblue]

Ack,
With regards to our A90 pictures and discussion, I finally got around to adding the extra lighting to my overhead microscope, and got a really good profile of the stylus. Went to take a photo and found that the scope's USB camera was dead. The drivers would see it, but no video. Drat. So I mickey-moused my Dino-scope setup to squeeze in under the overhead scope, and with careful juggling of the tonearm wand (a detached one) got a couple of photos that were almost as good as the one that got away.



In the first one, we're looking almost straight down and you can see the reflection of the narrow facet on one side. In the second picture you're looking more toward the entire leading edge of the stylus and can see the reflections of both facets and both sides of the tip.

What I find especially interesting is that at the angle of the second picture, it *appears* that we (the camera) are more or less on-axis to the thin facet that runs between the leading edge and the surface that backs it, upward. Now, it may be that that facet should be what is considered to be set at the SRA (91-92 degrees) which would lower the back of the arm considerably for the correct tracking angle. As opposed to the leading edge itself that we have been referencing, which results in a disagreement between the suggested parallel-to-the-record arm position, and what seems to be the correct SRA by positioning the arm tail up. And that, seems to increase the cantilever angle to in excess of 26 degrees, which is in disagreement with what Ortofon says it should be.

If the actual contact line of the stylus is at the rear of the facet, then there may be a different problem with tracking high modulation lateral movement, as the facet appears to be too broad to allow the stylus to negotiation the very tight groove curves required.

Ack, I have spent an enormous amount of time with all sorts of adjustments, to the arm, stylus angle, mass matching and all that and have had absolutely no luck getting the A90 to track well. It does very well on most audiophile type pressings, but with anything that is even slightly overcut or of high modulation laterally, it can't maintain contact with the groove walls. The same on two different A90's and two different tonearms, but always with the flat leading surface adjusted in the range of 91 to 92 degrees. Perhaps that leading surface is not the angle to be judged -- which means there is nothing visual to use as a guideline when aligning these things. You have to go much lower than the appearance of 91 degrees vertical at the leading edge to be in the ballpark, and it's totally by ear or IM distortion measurements from there on.

Unfortunately I hadn't seen these pictures of the facet in question and had pretty much given up on A90's in general, though I do really like the overall sound of them. Mis-tracking of any kind is something I can't abide.

What do you think? Could we be misinterpreting what guide to use for the correct SRA?

I couldn't find any of your original diagrams showing the facets to ID the one I'm referring to by number, so I hope you understand what I'm describing.

For the time being I have a Zyx R1000 Airy 3 SB in my ET2 which is doing a splendid job of tracking everything.

--Bill

 

[ack]

I don't see much difference between these pictures and what we have been discussing in that other thread some time ago. The only difference I think I see is what I believe looks like a concave part of Facet 39 in the triangle formed by the tracking edges. Here's what I mean:

The orange arrows point to Facet 39 that must be vertical for 0 SRA. The pink arrow points to one of the tracking edges. Compare both to the last picture from vinylengine:


Here's again another annotated picture of your stylus profile from the other thread, to aid in the analysis


The vinylengine Gyger depiction


A few more observations: Facet 39 in the first picture extends beyond the blackened part where I placed the orange arrow - the black part is obviously the general contact area which is affected by heat - see second picture for verification. The actual contact area remains the two tracking edges as we have discussed before, as also prescribed by the Gyger patent. I am not sure what purpose the alleged concave part of Facet 39 serves, but perhaps it's a scoop for dirt??? Or perhaps it's not concave and I am being misled by the reflections...

So if you have done everything right, I am not sure why you can't get the A90 to work right... I really don't think we are misinterpreting anything here... Therefore I have a few questions:

1. What do you mean exactly when you say you can't get to track well, and especially by "it can't maintain contact with the groove walls" - how does this mistracking manifest itself?
2. Are you still within the recommended tracking range, after SRA adjustment? As I've said before, I strongly believe we must maintain this relationship
3. I assume the A90 is properly aligned before these adjustments?
4. Have you calculated the arm/cartridge resonant frequency? Basically, how does the cart's compliance map to your arms' effective mass? Mine is 9.25Hz (10.5g arm effective mass, 8g for the cart, 16 µm/mN compliance), nearly perfect. I use something like this calculator
   

As discussed in the past, a very easy way for me to assert SRA is with sibilance, like Krall's Live In Paris ORG edition; any non-perfect setting is audible as unnatural sibilance. This is exactly due to tracking by those edges exclusively, and not by a wider contact area. But when it tracks exactly correctly, it's supposed to be more accurate - that's the basic premise of the Gyger stylus and its attempt at closely replicating the cutting stylus.

When I inquired Ortofon about Facet 39 being the visual vertical guide they said Yes, and this is what I would expect from the Gyger patent as well; I am certain the reason Ortofon mounts the stylus as shown is to help us in these adjustments (if you recall, there are two ways to mount the stylus as per patent, and the second is apparently used in the Lyra Atlas as per Fremer's pictures in the May 2012 Stereophile article I mentioned earlier)

So when you say:

always with the flat leading surface adjusted in the range of 91 to 92 degrees. Perhaps that leading surface is not the angle to be judged -- which means there is nothing visual to use as a guideline when aligning these things. You have to go much lower than the appearance of 91 degrees vertical at the leading edge to be in the ballpark, and it's totally by ear or IM distortion measurements from there on

I don't see how this can produce better results... The other problem I can see from past discussions is that you base your angle measurements using the USB microscope's software - the reason I developed the mathematical approach is because I couldn't really trust the manual approach of measuring the angle with the software (it's not the software per se, but the manual angling of the measuring angle device), thus I couldn't trust the resulting angle it claimed I had... You may want to try my approach as per post #52 one last time, and then fine-adjust by ear within +-0.5mm, as this gave me the best results...

 

[bblue]

I don't see much difference between these pictures and what we have been discussing in that other thread some time ago. The only difference I think I see is what I believe looks like a concave part of Facet 39 in the triangle formed by the tracking edges. Here's what I mean:

The orange arrows point to Facet 39 that must be vertical for 0 SRA. The pink arrow points to one of the tracking edges. Compare both to the last picture from vinylengine:
View attachment 3427

Here's again another annotated picture of your stylus profile from the other thread, to aid in the analysis
View attachment 3426

The vinylengine Gyger depiction
View attachment 3424

A few more observations: Facet 39 in the first picture extends beyond the blackened part where I placed the orange arrow - the black part is obviously the general contact area which is affected by heat - see second picture for verification. The actual contact area remains the two tracking edges as we have discussed before, as also prescribed by the Gyger patent. I am not sure what purpose the alleged concave part of Facet 39 serves, but perhaps it's a scoop for dirt??? Or perhaps it's not concave and I am being misled by the reflections...

If you look at my picture #2 you'll see that concave (or at least angled) area.

My concern is based on the view of the 'edge' showing a full reflection at the angle I was positioned. That suggests that perhaps the groove contact 'edge' is following a different angle than that of the leading face of the shank. If it was formed by the junction of the concave section and the main shank, the angle could conceivably be steeper than the shank view would suggest, requiring the arm to be lowered in the rear (and become more parallel to the record) to agree. Keep in mind that the part that is really 'in' the groove is only the very tip. All the mass we see above that (which is the majority) is practically irrelevant depending on exactly how the tip is angled.

So if you have done everything right, I am not sure why you can't get the A90 to work right... I really don't think we are misinterpreting anything here... Therefore I have a few questions:

1. What do you mean exactly when you say you can't get to track well, and especially by "it can't maintain contact with the groove walls" - how does this mistracking manifest itself?
2. Are you still within the recommended tracking range, after SRA adjustment? As I've said before, I strongly believe we must maintain this relationship
3. I assume the A90 is properly aligned before these adjustments?
4. Have you calculated the arm/cartridge resonant frequency? Basically, how does the cart's compliance map to your arms' effective mass? Mine is 9.25Hz (10.5g arm effective mass, 8g for the cart, 16 µm/mN compliance), nearly perfect. I use something like this calculator

1. You can hear it lifting vertically (out of phase distortion) whenever it cannot maintain contact with the groove walls. It can also be clearly seen on an XY scope display.
2. My target is always 2.3g VTF. As well, I have tried it as high as 2.4 and as low as 1.8. Nothing outside the 2.3 range works as well.
3. Of course.
4. I don't use calculators because the manufacturers numbers are seldom accurate. Instead I measure both horizontal and vertical resonance with sweep tones.

As discussed in the past, a very easy way for me to assert SRA is with sibilance, like Krall's Live In Paris ORG edition; any non-perfect setting is audible as unnatural sibilance. This is exactly due to tracking by those edges exclusively, and not by a wider contact area. But when it tracks exactly correctly, it's supposed to be more accurate - that's the basic premise of the Gyger stylus and its attempt at closely replicating the cutting stylus.

Understood. Sibilance marks the start of mis-tracking, or at the very least, mis-tracing due to groove pinch effect on too large of a stylus. It occurs with high lateral modulation (vocals are prime) in combination with high frequency content. Either one of these two situations (as well as VTF too light) will cause the stylus to lift vertically on high modulation.

With the A90, regardless of how I have had it set up (and a variety of experimental settings as well) a record that has particular parts that cause it to mis-track will *always* do it to some extent. Sometimes shifting SRA slightly will improve it (there's a 'dip' in sibilance as you cross over the ideal spot), but it is never gone. Other cartridges have no problems with the same places in the same records.

Another thing which is fascinating to watch when viewing an XY scope plot of the A90 trying to track/trace a difficult groove is to install a high-pass filter at about 8k ahead of the scope and observe (and listen to) the results. Keeping in mind that an XY display is the actual movement path of the stylus. You see all sorts of non-linear tracking events, especially surrounding vocals that are center channel.

Still another clue is observing a spectrum analysis of the cartridge output. If it's tracking well, there will seldom be anything above (roughly) 35k frequency content, and that only in the extremes. On an A90, it is routinely well over 64k. The higher out it goes, the more stylus chatter and noise there is, indicating some serious tracking/tracing problems. I watch all this stuff during record play and transcriptions. On my Zyx, the high frequency only (8k Hi-pass) is very linear with no odd movements or contortions. Frequency content seldom exceeds 30k.

When I inquired Ortofon about Facet 39 being the visual vertical guide they said Yes, and this is what I would expect from the Gyger patent as well; I am certain the reason Ortofon mounts the stylus as shown is to help us in these adjustments (if you recall, there are two ways to mount the stylus as per patent, and the second is apparently used in the Lyra Atlas as per Fremer's pictures in the May 2012 Stereophile article I mentioned earlier)

So when you say:
I don't see how this can produce better results... The other problem I can see from past discussions is that you base your angle measurements using the USB microscope's software - the reason I developed the mathematical approach is because I couldn't really trust the manual approach of measuring the angle with the software (it's not the software per se, but the manual angling of the measuring angle device), thus I couldn't trust the resulting angle it claimed I had... You may want to try my approach as per post #52 one last time, and then fine-adjust by ear within +-0.5mm, as this gave me the best results...

You still have to start from some known place, which is usually the stylus side view of a microscope (as we have been doing). Otherwise there is no reference on which to base the math.

On the ET2 SRA system, you have a total rear-of-the-arm movement (of an approximately 7" arm) of about .3 inches, displayed in .001 inch increments.

I suppose I could be totally missing something with the A90. But since I don't seem to have any problems with setup and good results of other cartridges, so far, at least, my conclusion is that the A90 is somehow flawed with regards to high modulation tracking/tracing. Either the line contact radius is too large (tracing 'pinching') or I've still not found a suitable tracking angle... which is very hard to imagine.

Some records that set it off to varying degrees include the GRP pressing of Cat Steven's Tea For The Tillerman, just about every track with strong lead vocal (tks 2,3,6 S1); Chris Isaak recent two record oldies set, most songs with strong mono vocals; most any MONO record with primarily vocals, etc. Easy listening music is mostly flawless because it's not demanding, Sheffield DTD are usually quite good unless a particular track has strong vocals in the center (Thelma Houston comes to mind). Etc.

--Bill

 

[ack]

If you look at my picture #2 you'll see that concave (or at least angled) area.

My concern is based on the view of the 'edge' showing a full reflection at the angle I was positioned. That suggests that perhaps the groove contact 'edge' is following a different angle than that of the leading face of the shank. If it was formed by the junction of the concave section and the main shank, the angle could conceivably be steeper than the shank view would suggest, requiring the arm to be lowered in the rear (and become more parallel to the record) to agree. Keep in mind that the part that is really 'in' the groove is only the very tip. All the mass we see above that (which is the majority) is practically irrelevant depending on exactly how the tip is angled.

Well, that's the million dollar question - is there another angle/facet at the tip or not. I don't think so, but I could be wrong; to me, your first picture depicts the tracking edges as a natural continuation of Facet 39; you would have been able to see them veering off at an angle, if there were another facet. The reflection that you see (and so do I) I interpret instead as a concave cut-out, as if someone went in with a spoon in that little triangle, and to me, that cut-out doesn't disturb what I see as the tracking edges being part of the same Facet 39. It looks to me as if someone went in with a very fine polishing tool and introduced that depression in order to exaggerate the tracking edges (Ortofon does claim the Replicant 100 is extra polished, but we don't know in what respect).

Perhaps Ortofon can chime in here...

You can hear it lifting vertically (out of phase distortion) whenever it cannot maintain contact with the groove walls. It can also be clearly seen on an XY scope display.

Yes, out of phase distortion is how I hear/perceive sibilance when rendered incorrectly - very audible, in fact. But I believe I fixed it; I should go back and re-test...

Sibilance marks the start of mis-tracking, or at the very least, mis-tracing due to groove pinch effect on too large of a stylus. It occurs with high lateral modulation (vocals are prime) in combination with high frequency content. Either one of these two situations (as well as VTF too light) will cause the stylus to lift vertically on high modulation.

Very interesting comment

With the A90, regardless of how I have had it set up (and a variety of experimental settings as well) a record that has particular parts that cause it to mis-track will *always* do it to some extent. Sometimes shifting SRA slightly will improve it (there's a 'dip' in sibilance as you cross over the ideal spot), but it is never gone. Other cartridges have no problems with the same places in the same records.

I wish I had another cartridge... but I recall that my previous XX-2 didn't stand out (in a bad way) with sibilance...

Another thing which is fascinating to watch when viewing an XY scope plot of the A90 trying to track/trace a difficult groove is to install a high-pass filter at about 8k ahead of the scope and observe (and listen to) the results. Keeping in mind that an XY display is the actual movement path of the stylus. You see all sorts of non-linear tracking events, especially surrounding vocals that are center channel.
...
Still another clue is observing a spectrum analysis of the cartridge output. If it's tracking well, there will seldom be anything above (roughly) 35k frequency content, and that only in the extremes. On an A90, it is routinely well over 64k. The higher out it goes, the more stylus chatter and noise there is, indicating some serious tracking/tracing problems. I watch all this stuff during record play and transcriptions. On my Zyx, the high frequency only (8k Hi-pass) is very linear with no odd movements or contortions. Frequency content seldom exceeds 30k.

Fascinating comments, but could all this just be the result of the claimed "deeper groove" tracking with this stylus? Would we be able to make the same observations with the Anna or the Atlas?

On the ET2 SRA system, you have a total rear-of-the-arm movement (of an approximately 7" arm) of about .3 inches, displayed in .001 inch increments.

I suppose I could be totally missing something with the A90. But since I don't seem to have any problems with setup and good results of other cartridges, so far, at least, my conclusion is that the A90 is somehow flawed with regards to high modulation tracking/tracing. Either the line contact radius is too large (tracing 'pinching') or I've still not found a suitable tracking angle... which is very hard to imagine.

Is the A90 flawed, or the Gyger stylus??? Do you consider the radius measurements of 5um/100um as claimed in the specs too large, too small, or something else?

It would be interesting to see if you can get even better up-close pictures of the tip...

 

[bblue]

Well, that's the million dollar question - is there another angle/facet at the tip or not. I don't think so, but I could be wrong; to me, your first picture depicts the tracking edges as a natural continuation of Facet 39; you would have been able to see them veering off at an angle, if there were another facet. The reflection that you see (and so do I) I interpret instead as a concave cut-out, as if someone went in with a spoon in that little triangle, and to me, that cut-out doesn't disturb what I see as the tracking edges being part of the same Facet 39. It looks to me as if someone went in with a very fine polishing tool and introduced that depression in order to exaggerate the tracking edges (Ortofon does claim the Replicant 100 is extra polished, but we don't know in what respect).

Usually it means the surface of the edges that are in direct contact with the groove wall.

Yes, out of phase distortion is how I hear/perceive sibilance when rendered incorrectly - very audible, in fact. But I believe I fixed it; I should go back and re-test...
...
I wish I had another cartridge... but I recall that my previous XX-2 didn't stand out (in a bad way) with sibilance...

The thing is that it may not have been for the same reason. With the XY scope and filter suite you can at least get an idea of what is transpiring mechanically. For example, some carts that mis-track sibilance do so with great stability. Meaning that the lateral movement is very controlled up to the maximum level where sibilance is pronounced. At that point it simply lifts vertically which is clearly seen as vertical modulation, possibly with the extreme edges of the lateral movement simply truncated. This can be an indicator of tracking too light.

Other cartridges/setups look quite spastic laterally even when they are not mis-tracking, meaning that the lateral movement is not 'flat' left to right. There's a lot of other lateral modulation variances seen, in addition to the lifting. This is the scenario that I see with the A90 stylus movement. It doesn't look controlled or linear laterally except on lower frequencies. The Zyx maintains its composure all the time.

...
Fascinating comments, but could all this just be the result of the claimed "deeper groove" tracking with this stylus? Would we be able to make the same observations with the Anna or the Atlas?

Good question. I don't think it's 'deeper groove' tracking, but rather significantly increased length of vertical contact with the groove wall. Something seems to be upsetting that relationship. The Anna is 'said' to be the same Replicant stylus as far as I've read. That may mean that the A90 problem is not the stylus per se, but mechanical properties of the cartridge itself. I'm not willing to gamble twice the price of an A90 on it.

Is the A90 flawed, or the Gyger stylus??? Do you consider the radius measurements of 5um/100um as claimed in the specs too large, too small, or something else?

5x100um is 0.2x4 mil, which is a remarkably thin contact edge, and I'd think way beyond the norm for tracing pinching effect. [Read that: excellent. ]

It is counter to what I'm hearing and seeing on instruments.

It would be interesting to see if you can get even better up-close pictures of the tip..

Don't I wish. That is as close as I can get with 220 power. There simply isn't any further without a much higher power scope and quality optics. My overhead (with the dead camera) goes just a little further (250) but I'd imagine we would need at least 400-500 power and higher intensity lighting to really start to see the finer detail. Maybe I'll look at an objective and eye piece power increase on the overhead scope and replace the camera.

As soon as I get done with my current project I'd like to try the A90 + wand again, but this time with more tail down on the arm to see how it behaves WRT the sibilance and mis-tracking. Truly, I'm pretty burned out on the A90, despite my highest of hopes and extensive time adjusting and testing.

--Bill

 

[bblue]

The Next Chapter

After dismissing the a90 for a few weeks and using just my Zyx RB1000 Airy 3 X SB, I decided to try the A90 again with a completely new setup.

The Zyx, for some unknown reason, has changed. When first installed and used for 10-15hrs, was almost perfectly parallel to the record (cartridge and arm) to achieve the proper SRA. I left it installed on the wand, and simply re-installed the same wand and setup. But now, the stylus angle has changed and I have to run it considerably tail-down to achieve the same SRA. It was capped and covered in a drawer between uses. The plastic mold that it's built in is now bubbly looking, as if it has changed form somehow. Despite the shift, it still sounds quite good when adjusted for correct SRA at 2.0 grams. It also does a pretty decent job of tracking/tracing, though not perfect. It just doesn't have the overall full A90 sound.

I used a new carbon fiber wand for the ET2 arm, no extra mass/weighting, and positioned the wand in the highest hole in the wand mounting assembly, which, with the A90 puts it almost exactly parallel to the surface of the record. I balanced vertical and horizontal mass to get a resonance of about 8hz horizontal and 11hz vertical. This time I set the VTF to 2.5g, up from the recommended 2.3g where I've always used it in the past. Upon playing a few LP's it was ok but not great in detail. Checking out the stylus angle, it was way low (too tail down even though parallel). Attempting to raise the arm tail up enough to put the stylus at 90 degrees proved to be quite a challenge. It required the entire ET2 assembly to be raised about 5/8" from its designed reference (which is the center of the air spindle at the record surface), AND the integrated adjustable VTA mechanism to be at the full top of its range. Those two things got the SRA to 90 degrees - just. I have no range to go higher. Here's a picture of just how much tails up that actually is.



Looks pretty excessive to me. But on well mastered and pressed records the sound is excellent. You'd never know it was a record except for the occasional surface tick. But on the usual tough to track records its tracking/tracing performance, even at the higher VTF, was still horrible. In fairness, I can't get it any closer to optimal SRA of between 90+1.5 to 2 degrees, so that may be a contributing factor.



In the above picture, the record surface is set exactly parallel to the horizontal baseline shown, and the vertical is 90 degrees, including the mirror refection from the vinyl.

Does anyone have any other suggestions on this? This is the second A90 I've had with a similar behavior. It's like the cantilever was simply not positioned correctly when the units were built. And no tracking force below 2.3g was acceptable.

The Zyx deteriorated (apparently) during storage, two A90's required far too much tail-up to be usable.

Can anyone recommend a great quality cartridge that is built to the right parameters and stays that way? I've been looking at either the Dynavector XX2-mk2, or VX-1s as a possible replacement. I need something with superb tracking and tracing, and wide, linear frequency response. Medium to low compliance most likely. Others have mentioned the Lyra Delos or Kleos as fitting my criteria.

Thanks for any feedback.

--Bill

 

[MylesBAstor]

Which ZYX are you referring to?

 

[bblue]

Which ZYX are you referring to?

In the first line of my message, "After dismissing the a90 for a few weeks and using just my Zyx RB1000 Airy 3 X SB, I decided to try the A90 again with a completely new setup."

--Bill

 

[MylesBAstor]

In the first line of my message, "After dismissing the a90 for a few weeks and using just my Zyx RB1000 Airy 3 X SB, I decided to try the A90 again with a completely new setup."

--Bill

Sorry don't know how missed that

 

[ack]

Hi Bill, sorry to hear about your tribulations. I came from the xx2 and the A90 is leagues above it. I've been meaning to follow up here, as I have done extensive A/B between the A90 and the same tracks on CD, and basically where sibilance is excessive in the recording the A90's rendition is slightly more distorted but that could also mean the CD mastering is different. Where the material is crystal clear, e.g. RR, it is simply trouncing the CD all across the spectrum. But - it HAS to be set up at +2 SRA. It's a tough beast to tame but I think I have it as optimally set up as possible.