Fantastic Service by Mehran Farahmand of Sora Sound

[Young Skywalker]

Would one be better served by purchasing several more “affordable” cartridges and selecting the one that sounds best in a level headshell and with a level armtube, or should one take their chances with a single unobtanium cartridge?

Between poorly manufactured (not to mention extremely expensive) vinyl records and a lucky dip among available cartridges it is all starting to feel like the antithesis of high fidelity or high end.

Is ignorance now bliss in the high end vinyl playback game?

 

[Young Skywalker]

@bonzo75 and @spiritofmusic , I am prepared to talk about specific cartridges and their issues (e.g., Ron’s and with his permission) but I don’t wish to talk about any brand generally unless it is to complement them on outstanding work across a broad range of samples seen in the lab.

The Straingauge and the TopWing are both great sounding cartridges.

If you were spending your hard-earned money (at full retail) on a top-flight MC cartridge today, which would YOU choose based on the wide sample evidence gathered in your lab? Let’s assume that one must have faith that this purchased cartridge was within acceptable tolerance to enable stellar performance with a level headshell (no shims) and arm tube parallel to the platter surface.

 

[PeterA]

Would one be better served by purchasing several more “affordable” cartridges and selecting the one that sounds best in a level headshell and with a level armtube, or should one take their chances with a single unobtanium cartridge?

Between poorly manufactured (not to mention extremely expensive) vinyl records and a lucky dip among available cartridges it is all starting to feel like the antithesis of high fidelity or high end.

Is ignorance now bliss in the high end vinyl playback game?

Interesting questions. I want to know what prompts people to send their cartridges to J. R. for analysis. Ron did it for his ZYX without first listening to his cartridges and then wrote about the experience and returned the cartridge for repair. He did the same with his Opus 1then had J. R. visit to install the cartridge.

Do most of J. R.’s customers do the set ups themselves and then hear a problem, or are they like Ron who hires an expert to do it for him?

I would like to read from hobbyists who actually do their own set ups and have made the before and after comparisons themselves.

As this thread is actually about Mehran’s wonderful service, I would also like to hear from some dealers about what they think about an inspection service from their perspective.

 

[mtemur]

It's commonly believed that the industry standard for SRA is 92.5 degrees, and most people aim for that. However, Kevin Gray recently announced that he cuts at 90 degrees. Considering that many reissues in people’s collections are cut by Gray, it’s surprising that no one is raising concerns about the 2.5-degree deviation and its potential impact on sound quality, let alone how to address it. There's a lot of discussion about adjusting SRA/VTA for each record based on thickness, but this only changes SRA by a fraction of a degree—a much smaller difference than the 2.5-degree variance in Gray’s cuts. Yet, no one seems to be addressing this.

I doubt Gray is the only engineer not sticking to 92.5 degrees, which makes me curious about what Bernie Grundman and Ryan K. Smith are doing.

After experimenting with different SRA angles, I found that 91-91.5 degrees works best for my setup and personal taste—your mileage may vary. I focused mainly on older pressings, rather than adjusting for Gray’s reissues. From my experience, small changes in SRA do affect the sound, but not as much as physical factors like balancing the tonearm with regular versus (supplied) additional rear weight, or using titanium or steel headshell screws. While it's important to set your cartridge optimally, preferably to standard values like 92.5 degrees SRA, I personally don't think it's worth adding a shim to correct a one- or two-degree SRA error. Physical tweaks can have a much more dramatic impact on sound. Additionally 92.5 degrees standard may not sound the best with your setup. Please do not bring up the topic that 92.5 is a mean value of 90-94 depending on a research and my record collection better suits for 91 degrees. Because unlike other setup parameters SRA/VTA is not really standard.

Take the Koetsu line, for example—the sound changes significantly just based on the cartridge body. Of course, manufacturers won’t admit this since they can't exactly say they’re overcharging you. BTW Mehran’s approach to this issue is a great example for other distributors and should be the standard, in my opinion.

 

[J.R. Boisclair]

It's commonly believed that the industry standard for SRA is 92.5 degrees, and most people aim for that. However, Kevin Gray recently announced that he cuts at 90 degrees. Considering that many reissues in people’s collections are cut by Gray, it’s surprising that no one is raising concerns about the 2.5-degree deviation and its potential impact on sound quality, let alone how to address it. There's a lot of discussion about adjusting SRA/VTA for each record based on thickness, but this only changes SRA by a fraction of a degree—a much smaller difference than the 2.5-degree variance in Gray’s cuts. Yet, no one seems to be addressing this.

I doubt Gray is the only engineer not sticking to 92.5 degrees, which makes me curious about what Bernie Grundman and Ryan K. Smith are doing.

After experimenting with different SRA angles, I found that 91-91.5 degrees works best for my setup and personal taste—your mileage may vary. I focused mainly on older pressings, rather than adjusting for Gray’s reissues. From my experience, small changes in SRA do affect the sound, but not as much as physical factors like balancing the tonearm with regular versus (supplied) additional rear weight, or using titanium or steel headshell screws. While it's important to set your cartridge optimally, preferably to standard values like 92.5 degrees SRA, I personally don't think it's worth adding a shim to correct a one- or two-degree SRA error. Physical tweaks can have a much more dramatic impact on sound. Additionally 92.5 degrees standard may not sound the best with your setup. Please do not bring up the topic that 92.5 is a mean value of 90-94 depending on a research and my record collection better suits for 91 degrees. Because unlike other setup parameters SRA/VTA is not really standard.

Take the Koetsu line, for example—the sound changes significantly just based on the cartridge body. Of course, manufacturers won’t admit this since they can't exactly say they’re overcharging you. BTW Mehran’s approach to this issue is a great example for other distributors and should be the standard, in my opinion.

I address these issues here:

 

[mtemur]

I address these issues here:

Well, I watched your video, thanks for sharing. I cannot say I don't agree with you except one thing, VTA. There is a misconception about it as if it's an angle but it's not. It is an arc and should be called Vertical Tracking Arc not Angle because the aim of reproducing stylus should be following the arc drawn by cutting stylus. Whether it's cutting or reproducing stylus a single parameter like vertical tracking angle alone cannot describe full physical characteristics of the vertical movement inside the groove.


It is called "Angle" in the above figure and everywhere else but it's not right. The most important thing here is that cantilever of the cutting stylus is much more longer than all cantilevers found in cartridges. Even if they look similar on the figure cantilever on cutting head is more than two times longer than cantilever on a cartridge. Obviously longer cutting cantilever draws a different arc compared to shorter cantilever of the cartridge even if they both at the same angle. If I summarize;
- A single parameter like angle is not enough to describe vertical movement.
- Aligning to same angle with cutting cantilever doesn't mean anything since cantilever lengths are different and cutting stylus cantilever is much longer.
- Even if you match the angle of cutting stylus (around 15-22) with your cartridge cantilever the arcs they draw will be different cause lengths of cantilevers are different.
- The purpose should be matching the arc of cutting stylus with your cartridge's stylus. Therefore Vertical Tracking Angle does not mean anything and it should be called Vertical Tracking Arc.
- I highly doubt that arc drawn by cutting stylus can be replicated by a cartridge due to length differences of cantilevers.
- Even if it's possible to follow the same arc with cartridge's stylus I doubt more about VTA's significance on sound considering there is incredibly small vertical movement compared to lateral. This is impossible to find out because VTA cannot be separated from SRA.

 

[J.R. Boisclair]

Well, I watched your video, thanks for sharing. I cannot say I don't agree with you except one thing, VTA. There is a misconception about it as if it's an angle but it's not. It is an arc and should be called Vertical Tracking Arc not Angle because the aim of reproducing stylus should be following the arc drawn by cutting stylus. Whether it's cutting or reproducing stylus a single parameter like vertical tracking angle alone cannot describe full physical characteristics of the vertical movement inside the groove.
View attachment 135790

The most important thing here is that cantilever of the cutting stylus is much more longer than all cantilevers found in cartridges. Obviously longer cutting cantilever draws a different arc compared to shorter cantilever of the cartridge even if they both at the same angle. If I summarize;
- A single parameter like angle is not enough to describe vertical movement.
- Aligning to same angle with cutting cantilever doesn't mean anything since cantilever lengths are different and cutting stylus cantilever is much longer.
- Even if you match the angle of cutting stylus (around 15-22) with your cartridge cantilever the arcs they draw will be different cause lengths of cantilevers are different.
- The purpose should be matching the arc of cutting stylus with your cartridge's stylus. Therefore Vertical Tracking Angle does not mean anything and it should be called Vertical Tracking Arc.
- I highly suspect that arc drawn by cutting stylus can be replicated by a cartridge due to length differences of cantilevers.
- Even if it's possible to follow the same arc with cartridge's stylus I doubt more about VTA's impact on sound considering there is incredibly small vertical movement compared to lateral. This is impossible to find out because VTA cannot be separated from SRA.

I think we are getting into obscurantist territory. Of course both the torque tube and the cantilever swing on an arc. Until we are prepared to make playback cantilevers at least 25mm long or have playback cantilevers with dual pivots, this is a realm we cannot do anything about.

But how much does it even matter? In the absolute worst case scenario, the variation in angles one versus the other is 0.54 degrees assuming a 25um minimum groove width and a 175um depth - and I'm *REALLY* stretching it.

VTA has not demonstrated itself to be particularly sensitive on a degree for degree basis as azimuth and zenith error are.

My stacked margin of measurement error for VTA is about +/-0.5 degrees and I'm very practiced at this. So, even if we did have a way to "fix" this difference, I'm not sure I - or anyone - could do something *reliable* about it given the size of the "fix" versus the size of measurement error.

 

[mtemur]

But how much does it even matter? In the absolute worst case scenario, the variation in angles one versus the other is 0.54 degrees assuming a 25um minimum groove width and a 175um depth - and I'm *REALLY* stretching it.

That's why I said this on my prior post.

- I highly doubt that arc drawn by cutting stylus can be replicated by a cartridge due to length differences of cantilevers.
- Even if it's possible to follow the same arc with cartridge's stylus I doubt more about VTA's significance on sound considering there is incredibly small vertical movement compared to lateral. This is impossible to find out because VTA cannot be separated from SRA.

I am not convinced significance of VTA.

 

[J.R. Boisclair]

That's why I said this on my prior post.

That is not how I understood your point. You were saying the differential in arc radius of a torque tube versus a playback stylus causes a new problem. I put that issue into perspective by doing some geometry to show it is not worth worrying about. This is VERY different than ensuring your *MEAN* VTA should be set to agree with the MEAN effective modulation angle for lowest distortion. I don't think this is debatable as this has been peer reviewed in professional journals AND is very audible when you control for other parameters.

I am not convinced significance of VTA.

I have a friend who literally couldn't see the color purple until he had neck surgery to relieve a pinched nerve. Now purple is his favorite color.

 

[mtemur]

You were saying the differential in arc radius of a torque tube versus a playback stylus causes a new problem. I put that issue into perspective by doing some geometry to show it is not worth worrying about

If the change in radius is not important why should the change in angle be important? That's my point.

I have a friend who literally couldn't see the color purple until he had neck surgery to relieve a pinched nerve. Now purple is his favorite color.

Maybe he lost a function that he doesn't want to talk as a compromise of surgery . Nerves are sensitive and can be easily messed.

 

[J.R. Boisclair]

If the change in radius is not important why should the change in angle be important? That's my point.

Because they are two errors of very significantly different magnitude and consistency. The average VTA error to the 18 optimal target (20 degree maximum acceptable) is 9 degrees across the several hundred cartridges we've analyzed.

During playback, VTA is changing to the degree that stylus friction will cause a change in VTA. Based on the work we've done to understand changes in VTA based upon changes in VTF, I'd say the difference is probably less than 0.2 degrees at *VERY* most but it depends on quite a number of factors, not least of which is STARTING VTA due to the reduction in influence of the vector force from stylus tip to tonearm horizontal pivot axis as VTA is lowered.

"Arc Error" (let's call it) has a maximum error of about 0.5 degrees and a mean error of something far less than that and it is constantly changing.