Koetsu

[mtemur]

Why is this?

cause a shim is an additional piece which is not in the original design of cartridge or tonearm. every cartridge has it’s own sound tuned with the shape and material of the body. same goes for tonearm too. an additional shim will alter the design, resonance and finally the sound of both cartridge and tonearm. I don’t want that.

 

[bonzo75]

cause a shim is an additional piece which is not in the original design of cartridge or tonearm. every cartridge has it’s own sound tuned with the shape and material of the body. same goes for tonearm too. an additional shim will alter the design, resonance and finally the sound of both cartridge and tonearm. I don’t want that.

I thought the shim is to be removed after installation based on reading this

Analog Corner #312: WallyTools & the WallyReference

Held every November in normal times, the annual Warsaw Audio Video Show is among the world's largest. I first attended a decade ago, in 2011, and was amazed by both the number of attendeesmore than 10,000 peopleand demographics that skewed young and included many families. That show was bigger...

www.stereophile.com

 

[DasguteOhr]

cause a shim is an additional piece which is not in the original design of cartridge or tonearm. every cartridge has it’s own sound tuned with the shape and material of the body. same goes for tonearm too. an additional shim will alter the design, resonance and finally the sound of both cartridge and tonearm. I don’t want that.

I can understand if you don't want that. i use it to add mass to the tonearm. some carts need heavyier tonearms because it makes a positive difference. That's the best way for me if your tonearm doesn't have a detachable headshell.

 

[tima]

Well that sounds like SRA can be set precisely and easily at 92 degrees but IMHO it‘s only true if ;
- you can measure height of the cartridge precisely
- you can set the tonearm precisely level with wally reference
- corrective shims were made really precisely
- your tonearm, shim and cartridge couples perfectly
- SRA of the stylus measured correctly in the first place.

There are lots of “if”s on this approach and those kind of multi-assumption approaches are not error free. Lots of things can go wrong on this formula. First of all you have to buy a wally reference and send your cartridge for measurement and still have to buy shims. And that’s only for one cartridge. After that you can hope SRA will be 92 degrees only if you measure cartridge’s height precisely, set your tonearm perfectly level and be able to couple tonearm, shim and cartridge error free. And that’s only true with the assumption of your cartridge’s SRA is measured precisely by this service.

IOT limit variables and to be free from multi-assumption approach that is prone to error, it’s better to;
- mount the cartridge to tonearm
- set the VTF
- measure and set SRA using a usb microscope by yourself.

It’s not easy to use a usb microscope but not hard either. Last but not least I don’t ever want a shim between my tonearm and cartridge. It will surely, absolutely and horribly effect the sound in a bad way.

Fwiw, JR is talking here about the Wally Reference which can use supplied shims if needed as part of its function to set the headshell parallel with the platter in both horizontal and vertical axes. They are not used with a cartridge, only the tool. When that is accomplished, the shims are removed with the tool. These are not the same as the shims he includes in his cartridge exam package to set SRA for installing with the cartridge, which is what you may be thinking..

I had the Wally's orginal VTA which handled only the vertical axis. The Wally Reference uses the same concept and it works well to establish the bottom of the headshell and presumably the cartridge as level/parallel with the platter.

I agree with you about putting something between the cartridge and the headshell; that it can change the resonance characteristics of the cartridge. Some carts like those from Lyra are designed to pass their resonance into the headshell.

 

[mtemur]

I thought the shim is to be removed after installation based on reading this

Analog Corner #312: WallyTools & the WallyReference

Held every November in normal times, the annual Warsaw Audio Video Show is among the world's largest. I first attended a decade ago, in 2011, and was amazed by both the number of attendeesmore than 10,000 peopleand demographics that skewed young and included many families. That show was bigger...

www.stereophile.com

I reread the page you mentioned. those shims are used just for measuring cartridge height with wally reference and not used during playback.
the shim I talk about is a different one, a correctional shim, made by wally tools AFAIK after examination of the cartridge and used IOT compensate SRA and azimuth error. that shim has to be installed between cartridge and tonearm and should stay there all the time during playback.

 

[mtemur]

Fwiw, JR is talking here about the Wally Reference which can use supplied shims if needed as part of its function to set the headshell parallel with the platter in both horizontal and vertical axes. They are not used with a cartridge, only the tool. When that is accomplished, the shims are removed with the tool. These are not the same as the shims he includes in his cartridge exam package to set SRA for installing with the cartridge, which is what you may be thinking..

thank you and @bonzo75 bringing up that. my OP based on the shim made after the examination as I explained in the prior post. the other ones used with wally reference IOT measure cartridge height are removed afterwards and not related. on the other hand the correctional one has to be in between cartridge and tonearm all the time. that’s what I’m against. if you think that I won’t use the shim made after the examination (the correctional one), then what is the point of sending your cartridge for examination and paying 500USD?

 

[mtemur]

I can understand if you don't want that. i use it to add mass to the tonearm. some carts need heavyier tonearms because it makes a positive difference. That's the best way for me if your tonearm doesn't have a detachable headshell. View attachment 97575

in your case you have to use a shim otherwise you can not use that specific cartridge with your tonearm because it’s too light. for those kind of situations using a shim as a weight is a necessity. otherwise you can not install cartridge to the tonearm. that’s not the best thing but perfectly alright IMHO.
on the other hand using shim for SRA, azimuth etc is not a necessity. you can align those paramaters without using a shim.

 

[Ron Resnick]

cause a shim is an additional piece which is not in the original design of cartridge or tonearm. every cartridge has it’s own sound tuned with the shape and material of the body. same goes for tonearm too. an additional shim will alter the design, resonance and finally the sound of both cartridge and tonearm. I don’t want that.

I agree that, in theory, one would not want that. But isn’t the proper question whether using a shim to correct a geometry defect in the positioning of the cantilever of the cartridge yields, in practice, a better sonic result than leaving it cattywampus with no shim??

 

[mtemur]

I agree that, in theory, one would not want that. But isn’t the proper question whether using a shim to correct a geometry defect in the positioning of the cantilever of the cartridge yields, in practice, a better sonic result than leaving it cattywampus with no shim??

You don’t need a shim to correct that geometry defect. Using shim for SRA, azimuth etc is not a necessity. you can align those paramaters without using a shim. It’s a better way to;
- mount the cartridge to tonearm
- set the VTF
- measure and set SRA using a usb microscope by yourself. Additionally it’s multi-assumption free. With cartridge examination service and correction shim method you have to hope that all the measurements and calculations went well and you obtained 92 degrees SRA. With usb microscope you don’t have to hope you can see it’s 92 degrees or not.

 

[J.R. Boisclair]

I think we tend to overestimate the design intentions and results of most cartridge tonearm manufacturers. I could write a long exposition on why managing resonance in a tonearm or cartridge is a capitulation to the unsuccessful management of more important design priorities, but that will have to be a subject for a technical paper. Managing resonance should not be the first design priority at all.

In any event, physical deflection transcription playback requires working from a predetermined hierarchy of design priorities. For the ultimate in faithfulness to the groove, rigidity must be the highest priority. That design priority then gets it’s necessary design and execution in practice to the best of the ability of the manufacturer. Since every execution is imperfect, secondary design priorities are employed to manage what the first priority could not fully accomplish, such as resonance control.
At some point, the design priorities require a careful balancing to get the highest fidelity. For example, some British tonearm manufacturers feel that rigidity at the headshell trumps the ability to maximize stereo separation by offering adjustment on the azimuth axis. Obviously, given the variance in cartridge assembly practices, I feel this is an unbalanced application of design priorities.

In any case, the question of what is the entire design priority hierarchy empirically necessary to get maximum fidelity is possible to answer with certainty, but doing so takes a serious investment in equipment, expertise and time, not to mention the time required for peer review of the results to ensure repeatability and consistency.

mtemur is right that the corrective shim will influence the sonic results, no matter what the material is made from. What I do not agree with is that it will always make things sound worse. If the angular correction required for a given cartridge can be accomplished with the tonearm, then the user is free to use the single bladed WallyReference to accomplish those angles and not use the corrective shim at all. Unfortunately, in more than 50% of my analyses, the cartridge requires more correction for SRA/VTA than the arm will offer. The owner then needs to make a choice to use the corrective shim and get the full angular correction or live with less in order to have a direct union between cartridge and headshell.

The distortions caused by SRA/VTA error are measurable. We have been doing this work and will eventually publish the paper for peer review. The question becomes, is the benefit I get from hitting all my targeted angles by using the corrective shim a NET positive considering that it WILL change the mechanical union between cartridge and headshell?

The answer to this is almost never certain and is based upon many factors, not the least of which is whether you will use the printed corrective shim, the milled brass corrective shim or our future developments in corrective shim material options.

Absent the time, ability and resources to model this up in finite element analysis and confirm results with laser vibrometry, we have only our ears to guide us.

One of our engineers reported that the sound of his Lyra Atlas with the basic corrective shim was an obvious net gain in sound quality though he gave up some “bass grip” (his cartridge required more SRA/VTA correction than the tonearm would allow). When he switched to the brass corrective shim, the “bass grip” was back and all other gains remained. This is consistent with what I have experienced and what I would expect from increasing the rigidity of the coupling.

I respect mtemur’s aversion. I felt the same way not long ago. I would only suggest he keep an open mind about it as he - like me! - continues to learn more about this crazy love of vinyl playback. Optimization is highly complex and not many principles of vinyl optimization come with an “always” or “never”. There are some times when we have to violate one principle to benefit another principle for a NET gain.

 

[tima]

With cartridge examination service and correction shim method you have to hope that all the measurements and calculations went well and you obtained 92 degrees SRA. With usb microscope you don’t have to hope you can see it’s 92 degrees or not.

If shim is predicated on 92 degrees, I will ask if 92 degrees is universal for all cartridges? What if my ears tell me different -- are my ears wrong?

 

[PeterA]

If shim is predicated on 92 degrees, I will ask if 92 degrees is universal for all cartridges? What if my ears tell me different -- are my ears wrong?

My question would be, if you set up four different cartridges on four arms on the same turntable each by only listening for best sound and then measured with a USB microscope and found four different angles, what does that mean?

 

[J.R. Boisclair]

If shim is predicated on 92 degrees, I will ask if 92 degrees is universal for all cartridges? What if my ears tell me different -- are my ears wrong?

Not at all! What is likely to be wrong is any assumption that it is specifically the SRA that is causing changes in sound when raising/lowering the tonearm.

SRA must be close to cutting rake to avoid mechanical distortions on horizontally modulated groove content. VTA must be close to torque tube cutting angle to avoid mechanical distortions related on vertically modulated groove content. This is not a point of debate and is easily modelled mathematically or in engineering software. What IS up for debate is what is the AVERAGE ideal angle at which we should aim our SRA and VTA for and (since they are in a locked relationship keeping us from being likely to hit BOTH targets) how we should weight the two variables to achieve the best compromise. We know the targeted SRA/VTA angles are in a tight range and isn't even close to zenith and azimuth/crosstalk in terms of sensitivity, but it certainly makes a difference. Stay tuned. This will be in a technical paper we will publish.

 

[J.R. Boisclair]

My question would be, if you set up four different cartridges on four arms on the same turntable each by only listening for best sound and then measured with a USB microscope and found four different angles, what does that mean?

Like a mosquito at a nudist colony, I wouldn't know where to begin (answering this)

Sorry, must wait for our paper on this one.

 

[mtemur]

SRA must be close to cutting rake to avoid mechanical distortions on horizontally modulated groove content. VTA must be close to torque tube cutting angle to avoid mechanical distortions related on vertically modulated groove content. This is not a point of debate and is easily modelled mathematically or in engineering software

For obvious reasons everyone accepts SRA must be close to 92 degrees. that’s ok. as you’ve stated above VTA must be close to cutting tube’s angle which varies between 16-22 degrees. VTA is not as important as SRA. that’s ok too. I’m with you till this point.
but in one of your previous posts you suggest correcting extreme manufacturing defects on SRA with a shim which will eventually highly alter VTA. it will also change the coils’ tilt angle (don’t confuse with orientation) too. I don’t think it’s a good idea.

my suggestion for this problem is:
-if SRA can be corrected within the height of tonearm as I explained before use a usb microscope and do it without using shim.
-if stylus mounted on the cantilever with a funny angle and SRA can not be corrected within the height of tonearm then send cartridge back for replacement. it’s a defect. don’t try to compensate it.

IMHO trying to correct a fault with other than perfect solution like adding shim opens a gate to other problems such as highly altered VTA, tilted coils and a change in sound.

 

[J.R. Boisclair]

For obvious reasons everyone accepts SRA must be close to 92 degrees. that’s ok. as you’ve stated above VTA must be close to cutting tube’s angle which varies between 16-22 degrees. VTA is not as important as SRA. that’s ok too. I’m with you till this point.
but in one of your previous posts you suggest correcting extreme manufacturing defects on SRA with a shim which will eventually highly alter VTA. it will also change the coils’ tilt angle (don’t confuse with orientation) too. I don’t think it’s a good idea.

my suggestion for this problem is:
-if SRA can be corrected within the height of tonearm as I explained before use a usb microscope and do it without using shim.
-if stylus mounted on the cantilever with a funny angle and SRA can not be corrected within the height of tonearm then send cartridge back for replacement. it’s a defect. don’t try to compensate it.

IMHO trying to correct a fault with other than perfect solution like adding shim opens a gate to other problems such as highly altered VTA, tilted coils and a change in sound.

In principle, I certainly agree with you. You have to be careful not to throw the baby out with the bathwater, so to speak. However, it is an exceedingly common condition of cartridge manufacturing today that VTA is too high (as mentioned before, there are interesting reasons behind this that have nothing to do with fidelity in playback) and the majority of SRA corrections require “butt down” on the cartridge which compliments the need to improve VTA (by lowering it) in almost all cases.

I am a bit confused on your point with regards to the inevitable change in angular orientation of the coil former when making significant adjustments to the SRA/VTA through use of a shim. On the cutterhead designs I am familiar with, there is an orthogonal relationship between the motor coils and torque/torsion tube (cutting cantilever). This is also certainly the case with playback cantilever assemblies. Therefore, the coils in cutting and the coils in playback always remain orthogonal to the cantilevers and this is why I am having difficulty seeing how it is a problem to simultaneously adjust the coil's angular relationship with the record surface in lock-step to changes to the VTA.

Perhaps I am not understanding your point?

 

[mtemur]

In principle, I certainly agree with you. You have to be careful not to throw the baby out with the bathwater, so to speak. However, it is an exceedingly common condition of cartridge manufacturing today that VTA is too high (as mentioned before, there are interesting reasons behind this that have nothing to do with fidelity in playback) and the majority of SRA corrections require “butt down” on the cartridge which compliments the need to improve VTA (by lowering it) in almost all cases.

I am a bit confused on your point with regards to the inevitable change in angular orientation of the coil former when making significant adjustments to the SRA/VTA through use of a shim. On the cutterhead designs I am familiar with, there is an orthogonal relationship between the motor coils and torque/torsion tube (cutting cantilever). This is also certainly the case with playback cantilever assemblies. Therefore, the coils in cutting and the coils in playback always remain orthogonal to the cantilevers and this is why I am having difficulty seeing how it is a problem to simultaneously adjust the coil's angular relationship with the record surface in lock-step to changes to the VTA.

Perhaps I am not understanding your point?

I will try to explain what I meant in my prior post but please excuse my limited English knowledge.

a change in VTA about 1 or 2 degrees is negligible in order to set SRA exactly at 92 degrees IMHO. but if a cartridge needs a high SRA correction which is over the range of tonearm's adjustable height and corrected using a shim can lead to high VTA change. for example if cartridge needs 10 degrees of SRA correction and if it's original VTA is 20 degrees then final VTA will be 10 or 30 degrees depending on the way of required correction. as all of us know VTA is not as important as SRA but 10 degrees change on VTA for the sake of correcting SRA is excessive and it will have an effect on reading vertical undulations of the grooves. simply stereo bass (or any out of phase material). improper VTA will also increase distortion.

when you change VTA or any other parameter obviously record's surface and angle of the grooves will not change. therefore a stylus riding in those grooves will always move according to the undulations inscribed to the grooves no matter what the VTA is (assuming perfect SRA for all cases). in short, grooves will always cause the same movement on the stylus tip (but different arc) no matter what the VTA is but when a change in VTA happens, for example 10 degrees the relative angle between record surface plane and coils' plane (or motor) will significantly change too.

since the direction and force of vectors introduced by the groove undulations are not changing but relative angle between the record surface and cantilever (also coils or motor) is changing the read out from the cartridge will be different. because cantilever's and coils’ angle will not match the cutting head tube's and coils’. when stylus moves up and down due to vertical undulations the arc drawn by the stylus will be different than the cutting head's. as a result voltage induced on coils (ore motor) will change and it will cause an increase on distortion. that is still relatively small compared to misaligned SRA.

anyway it is paramount to achieve 92 degrees of SRA but in order to do this a large deviation from optimum VTA (16-22 degrees) should be avoided. IMHO since SRA and VTA are interlinked by the cantilever a cartridge which requires a high amount of SRA correction that is beyond the ability of tonearm should be replaced.

 

[J.R. Boisclair]

I will try to explain what I meant in my prior post but please excuse my limited English knowledge.

a change in VTA about 1 or 2 degrees is negligible in order to set SRA exactly at 92 degrees IMHO. but if a cartridge needs a high SRA correction which is over the range of tonearm's adjustable height and corrected using a shim can lead to high VTA change. for example if cartridge needs 10 degrees of SRA correction and if it's original VTA is 20 degrees then final VTA will be 10 or 30 degrees depending on the way of required correction. as all of us know VTA is not as important as SRA but 10 degrees change on VTA for the sake of correcting SRA is excessive and it will have an effect on reading vertical undulations of the grooves. simply stereo bass (or any out of phase material). improper VTA will also increase distortion.

when you change VTA or any other parameter obviously record's surface and angle of the grooves will not change. therefore a stylus riding in those grooves will always move according to the undulations inscribed to the grooves no matter what the VTA is (assuming perfect SRA for all cases). in short, grooves will always cause the same movement on the stylus tip (but different arc) no matter what the VTA is but when a change in VTA happens, for example 10 degrees the relative angle between record surface plane and coils' plane (or motor) will significantly change too.

since the direction and force of vectors introduced by the groove undulations are not changing but relative angle between the record surface and cantilever (also coils or motor) is changing the read out from the cartridge will be different. because cantilever's and coils’ angle will not match the cutting head tube's and coils’. when stylus moves up and down due to vertical undulations the arc drawn by the stylus will be different than the cutting head's. as a result voltage induced on coils (ore motor) will change and it will cause an increase on distortion. that is still relatively small compared to misaligned SRA.

anyway it is paramount to achieve 92 degrees of SRA but in order to do this a large deviation from optimum VTA (16-22 degrees) should be avoided. IMHO since SRA and VTA are interlinked by the cantilever a cartridge which requires a high amount of SRA correction that is beyond the ability of tonearm should be replaced.

I think we are both on the same page, Mtemur!

The most I've ever corrected SRA by is somewhere around 7.5 degrees (most cartridge bodies won't allow this much). I would not have made this correction at all if VTA at level headshell was at only 20 degrees. I have seen 8 to 16 degrees SRA error and those egregious offenders will always go back to the manufacturer. Typically, required SRA correction is negative (meaning, tonearm needs to drop) and most all cartridge VTA is too high to start with anyway, so the VTA dropping with SRA is typically a benefit for both SRA and VTA.

Here's some SRA stats from my analysis database of a few hundred cartridges analyzed:

	Degrees
Average Rake Error	3.31
Median Rake Error	2.94
Average Rake Error (too high)	3.55
Average Rake Error (too low)	2.94
Maximum Rake Error	16.00
Rake Error Standard Deviation	2.53

Here's the VTA stats. Note they are figures AFTER SRA correction. You can see how high things are!

Average Static VTA - rake corrected	24.35
Median VTA	24.38
Maximum VTA	33.16
Standard Deviation	3.81

 

[mulveling]

@J.R. Boisclair
Fascinating! If you have the SRA statistics filtered to Koetsu brand cartridges (and possibly further by rough age brackets), that would be of great interest to many of us here in the Koetsu thread

 

[J.R. Boisclair]

@J.R. Boisclair
Fascinating! If you have the SRA statistics filtered to Koetsu brand cartridges (and possibly further by rough age brackets), that would be of great interest to many of us here in the Koetsu thread

Hi @mulveling ,

I am comfortable with sharing the stats of the industry as a whole, but not comfortable with sharing detailed data on individual brands. There are a few reasons for this, but mostly because I know they all have tolerance challenges to greater or lesser degrees and picking on one would be a suggestion that others "are better". Koetsu has the same problems all the others do, particularly because of the type of stylus profile they have chosen for their cartridge. Yes, Gyger replicant styli are generally much better aligned (they are also FAR easier to image and measure!) than Ogura or Namiki profiles, but they have a downside: they degrade relatively quickly. Koetsu does not use Gyger for the top end cartridges - or any of their cartridges, as far as I know.

The other reason is that not all of my stats on individual brands have datasets large enough to be statistically significant. It would be irresponsible for that reason alone to share data that wasn't robust enough to be a reliable sample of the general construction quality. I have analyzed 33 or 34 brands by now but some of them have been seen only a small handful of times.

The only thing I am comfortable saying in public about the Koetsus is that they are doing a great disservice by "hiding" the cantilever. I measure the angular relationship between the body and the cantilever on all my analyses and I know that we cannot be aligning our cartridges by their bodies. Besides the bodies being TWICE removed from the part that matters (the stylus' contact edges), the bodies are rarely orthogonal to the cantilevers - not to mention whether the stylus contact edges are orthogonal to the cantilever.

At the request of a couple cartridge manufacturers, I have shared brand-specific data with them in an effort to help them make better cartridges, but I'd otherwise rather keep the data to myself for now. Sorry to disappoint.