Calling Adjust+ experts...

ianm0

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Feb 22, 2018
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Allow me to revive Tima's discussion on Adjust+. The phase angle was close to 0 deg for one channel and approx 180 for the other. The crosstalks matched to around 3-5 db.


I have a Shelter 901 and it shows exactly the same behavior, but it sounds bloody good even after I have owned it for well over 10 years and a couple of retips. In Tima's case I wonder if the cartridge sounds good at -1.5 deg azimuth?
Now a bit of theory. The phase difference should be in the range of either 0 - 360 or -180 - +180. Adjust+ only shows 0 - 180 deg. I am not sure if Dr Feikert has used the range -180 to +180 and then take the absolute value or what did he do something else. Does anyone have any inkling?

Also, Tima, have you solve the conundrum?
 
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Brian Walsh

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Looking at the curves, I'd estimate the optimum azimuth setting will be in the 2.5 to 3.0 degree range, where the phase curves intersect. That's as extreme as it gets and generally not recommended considering record and stylus wear. I would be getting the cartridge rebuilt or replaced.
 
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bazelio

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Looking at the curves, I'd estimate the optimum azimuth setting will be in the 2.5 to 3.0 degree range, where the phase curves intersect. That's as extreme as it gets and generally not recommended considering record and stylus wear. I would be getting the cartridge rebuilt or replaced.

How does the 2-3 degree azimuth negatively affect record and stylus wear? The stylus should be aligned correctly in the groove at that setting according to the measurements.
 

MPS

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Now a bit of theory. The phase difference should be in the range of either 0 - 360 or -180 - +180. Adjust+ only shows 0 - 180 deg. I am not sure if Dr Feikert has used the range -180 to +180 and then take the absolute value or what did he do something else. Does anyone have any inkling?
I think it's not about absolute phase but phase difference between the channels. 360 difference would end up being equal phase or 0 degree difference so 180 degrees difference is the highest possible. I guess 180 degrees difference would result if one channel had wires crossed, at least in case of ideal cartridge.
 

ianm0

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Feb 22, 2018
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I think it's not about absolute phase but phase difference between the channels. 360 difference would end up being equal phase or 0 degree difference so 180 degrees difference is the highest possible. I guess 180 degrees difference would result if one channel had wires crossed, at least in case of ideal cartridge.
Two points:
1. The plot in my post was from tima's OP, not for my cartridge.
2. I understand it is the phase difference displayed is that between main signal and crosstalk. This phase difference could assume the two ranges I mentioned. Note: 190 in one range = -170 in the other. For example: sin (190) = sin (-170). So the choice is identical mathematically. That's why I don't understand why Adjust+ only shows the range 0 - +180. I have used PC's software (Visual Analyzer) to measure the phase difference and it did confirm the difference could be more than 180 in some measurements.

Below is a crosstalk measurement using Visual Analyzer showing the phase difference at 1000 hz is larger than 180:
1588646813300.png

Allow me to dig deeper into theory, although this is just a guide/approximation due to the complex nature of the problem.
The phase difference is given (very approximately) by the relation:
tan (phase difference) = 2* pi * 1000*L/R, where L and R are respectively the self inductance and DCR of the coil giving rise to the signal (not crosstalk). L ~ 1 mH, and R ~ 1-15 ohms.
For 2 mH and 10 ohm, it's about 50 deg; for 5 mH and 5 ohms, it's about 80 deg. ....In one of Dr Feikert's presentations, his charts showed values around this range.
Note: there may be other sources giving rise to extra phase shift, but I do not claim to understand it. I am all ears to the wisdom of others.
 
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ianm0

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Feb 22, 2018
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Hi Tima

Did you post the measurements of the replacement? I am interested to see the phase plots.The reason I asked is I'm not sure if plots in #23 are those of the replacement cartridge.
 
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Brian Walsh

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How does the 2-3 degree azimuth negatively affect record and stylus wear? The stylus should be aligned correctly in the groove at that setting according to the measurements.
Maybe, maybe not. I'd have to see the angle of the stylus relative to the groove, not the angle of the cantilever. Chances are the stylus is canted, in which case it's not something you want for acceptable record and stylus wear. The electrical performance measured suggesting such adjustment can be due to several factors.
 

bazelio

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Maybe, maybe not. I'd have to see the angle of the stylus relative to the groove, not the angle of the cantilever. Chances are the stylus is canted, in which case it's not something you want for acceptable record and stylus wear. The electrical performance measured suggesting such adjustment can be due to several factors.
Either or both the stylus and cantilever can be askew, requiring compensation. One should align the stylus, not the cantilever, when setting zenith. But I'm asking a different question. Once the left/right channel measurements indicate proper groove alignment, what is it about a 2-3 degree azimuth compensation that is bad? My friend at Soundsmith who rebuilds cartridges has told me that, while they tend to achieve higher accuracy, a few degrees is perfectly acceptable in general.
 
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tima

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Either or both the stylus and cantilever can be askew, requiring compensation. One should align the stylus, not the cantilever, when setting zenith. But I'm asking a different question. Once the left/right channel measurements indicate proper groove alignment, what is it about a 2-3 degree azimuth compensation that is bad? My friend at Soundsmith who rebuilds cartridges has told me that, while they tend to achieve higher accuracy, a few degrees is perfectly acceptable in general.

Uneven groove and/or stylus wear?
 

bazelio

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Assume a brand new record and cart. Let's not introduce hypothetical external factors, but just address nominal conditions.
 

Brian Walsh

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Either or both the stylus and cantilever can be askew, requiring compensation. One should align the stylus, not the cantilever, when setting zenith. But I'm asking a different question. Once the left/right channel measurements indicate proper groove alignment, what is it about a 2-3 degree azimuth compensation that is bad? My friend at Soundsmith who rebuilds cartridges has told me that, while they tend to achieve higher accuracy, a few degrees is perfectly acceptable in general.
If the stylus is reasonably close to the standard orthogonal orientation to the record surface when viewed from the front, you may be OK. It would be strange and disconcerting for a stylus to be that far off, though.
 

ianm0

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Feb 22, 2018
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I have a question about the innards of a MC cartridge. Is there any motion of the coils RELATIVE to the stylus and to each other when the stylus is playing? Anotherway to phrase the question: do the stylus/coils move together as a RIGID system when a record is played?
 

MPS

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I have a question about the innards of a MC cartridge. Is there any motion of the coils RELATIVE to the stylus and to each other when the stylus is playing? Anotherway to phrase the question: do the stylus/coils move together as a RIGID system when a record is played?

In principal, yes.
 

Brian Walsh

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I have a question about the innards of a MC cartridge. Is there any motion of the coils RELATIVE to the stylus and to each other when the stylus is playing? Anotherway to phrase the question: do the stylus/coils move together as a RIGID system when a record is played?
What MPS said. But realize that nothing in this world is completely rigid. That certainly includes coils which can vibrate - and do. When you hold a wooden ruler down on a table and sticking out over the edge and pluck it, it does a "boing" even though it's pretty rigid normally. Metal does, too, just differently and to a different degree. So back to your question, the coils move (and vibrate) microscopically relative to the stylus and cantilever, unintentionally of course. The cartridge designers select materials and dimensions to be as rigid and free of resonances as possible. For example, cartridges can have aluminum, boron, diamond, etc. cantilevers.
 

ianm0

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Brian
Thanks. That's what I suspect. I think I might have a handle to understand the physics behind tima's plots I reproduced in post #41. But one point still bothers me. So I'll keep it to myself for now.
 

bazelio

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If the stylus is reasonably close to the standard orthogonal orientation to the record surface when viewed from the front, you may be OK. It would be strange and disconcerting for a stylus to be that far off, though.

Back to the question of 2-3%, I learned today that Namiki cantilever-stylus assemblages have a +/- 3% tolerance on VTA, Azimuth, and Zenith alignments. Many if not most cartridge companies use Namiki since very few are capable of mounting a stylus to a cantilever. So 3% is actually the industry standard for what is considered acceptable. But if 3% bothers someone and their particular cart manufacturer is willing to replace it, then more power to them.

Unrelated, it still boggles my mind that Soundsmith is able to reliably mount a tiny stylus to a cactus needle. Props to Peter.
 

tima

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Electrical components (caps, resistors, etc.) have +/- n% tolerances. Some brand's tolerances may be tighter than others. Likewise audio component manufacturers have their tolerances of acceptability as well, some tighter than others. In their effort to build higher quality, higher consistency and higher reliability components it is not that uncommon for a component manufacturer to have a part rejection rate of 2 out of 3. It is one of the things that differentiates components and drives up cost.

It would not surprise me if something similar held for cartridge manufacturers. Out of all the cartridges on the market, my personal expectation is that an $8k - $20k+ cartridge is a higher quality cartridge, built to a higher standard than lower priced cartridges.

Apart from some theoretical argument, it does not seem unreasonable for an end-user to concern themselves with both optimal sound and stylus wear and groove damage that a less than perpendicular stylus mounting may cause - regardless of an industry standard.
 

bazelio

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Many of your $10k and beyond cartridges use Nakimi sttylii. They supply even the all-diamond cantliever stylus assemblages found on megabuck products. And, in this thread, we haven't yet established that any such damage actually occurs when a 2-3% error is compensated by proper alignment. Nor is it intuitive that any such damage actually would occur.

PS the claim being made here is simply that 2-3% is unacceptable. Not "if cart_cost > 8k then 2-3% not(acceptable)". And I don't expect cost to be a function of part rejection (if in fact it even occurs). I expect "rejected" parts to be relegated to lower end products in a line at best. And even then, the hand assembled generator system is further subjected to human tolerances anyhow. 2-3% still seems reasonable and safe for the end product which is a root sum square of uncorrelated errors.
 
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bazelio

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https://www.ad-na.com/en/product/jewel/product/cantilever.html

Looks like Zenith is actually +/- 5° there. And by the way, the $15,000 Opus1? It uses the pre-mounted Namiki boron - a $50 part. Do they toss outliers? We can't know, but at $15k, they certainly can afford to do so.. As I said in #32, cart mfgs do try account for it when aligning a stylus to the generator and aligning the generator to the body. At the end of the day, there will be a summation of errors, and I believe the word of folks I know who rebuild carts of all makes and models for a living when they say that a net of two to three degrees is acceptable. But if they're wrong, I'd love a clear and concise explanation as to why.
 

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