[dlaloum]

Assuming I had an LCa (I don't) - then I would say that I am not measuring the right thing.... and have to work out what to measure!

I do however have a TK7su (needle-less) - which I have tried with the ATN20ss - seems to me to be identical to the AT20.... except in my case the AT20 is the better one - by measurement - impossible to differentiate them audibly.

I mixed the LCa up with the SU earlier...

I just got hold of an unopened NOS AT160ML - which should be a lot closer to the TK7LCa than the AT20ss... (another cartridge to get around to - but I couldn't miss the chance, as they are not thick on the ground now)

[Halcro]

Speaking of the TK7SU.....I find it understandably similar in most respects to the TK7LCa.....
Bear in mind that I have tested most of my cartridges in at least 3 arms and some up to 6 arms...
I can only assume that my AT20ss must have been seriously defective to explain this puzzling divergence of experience...

[Halcro]

Just to clarify for those unfamiliar with the Signets....the only 'revealed' differences between the 7LCa and the 7SU is one uses a line contact stylus whilst the other uses a Shibata...

[dlaloum]

Also the generators are the same spec for AT15/20 and TK7SU/LCa...

But the needles differ between AT15/20, AT20ss, TK7Su and TK7LCa

I believe that the Su needle should be identical to the SS but cannot confirm that, and the LCa should be a step up as it was the first AT needle to go beyond the Shibata to an even finer line contact....

However what I can confirm is that the 15/20/Su all have the same generator (within variances of manufacturing)

Although I would expect a marginally improved performance from the LCa, I would not expect a night and day difference as you are describing....

On the other hand.... the TK7 body is heavier than the AT20 body, and I think the Signet stylus holder has more inherent damping - so it may be something much more subtle in terms of resonance control and interaction with headshell/arm.

I believe you also said at one point that you got best performance from the TK7 on wooden headshells? (was that you?) - cos that type of response seems be a strong pointer to damping/resonance related issues.... (and therefore the potential for concomittant differences on various arms ...)

[Halcro]

David,
I generally have found that all my metal-bodied cartridges sound best in a wood (or plastic in the case of the Copperhead) headshell...whilst plastic-bodied ones I have found sound best in metal or ceramic headshells 

[neobop]

If the generators of the 7Su is the same as the 20, then the 7LCa is odd man out.  It's 5mV, 550mH, 800/900 ohms.

The 7Su is an earlier generation having a round plug?  I believe the 7LCa has a 100 series rectangular plug.

neo

[dlaloum]

Yes the su has the earlier round plug...

[neobop]

Regarding contact area:
This is an illustration of relative contact area of tips used in the '70's



This might not be 100% accurate, but it gives an idea of sidewall contact area.  Modern micro tips have much narrower and longer contact area than shibata.  A .7 spherical can't trace some of the narrowest groove undulations, but it doesn't sound like there's anything missing until you make a comparison.   

We tend to think in absolutes - all or nothing, but that is not the case.  Some people prefer less detail in favor of a more "musical" presentation if the cart can deliver. 
neo

[dlaloum]

The LC / LP tips used by AT after the Shibata's (on the LCa, 155LC, 140LC, 152LP etc...) were according to AT a modified Shibata design.

I believe that they are symmetrical front and back which results in a straight contact patch rather than the Shibata's lightly curved patch. (the original Shibata is asymetrical front to back)

The Shibata profile is apparently one of the easier (and therefore cheaper!) ones to cut and polish, which is I think why it is suddenly coming back into vogue now that supplies of the more exotic line contact designs are either drying up (FG) or becoming more expensive (Namiki / Ogura)... The side profile is marginally narrower than 0.3mil elipticals and slightly wider than 0.2mil elipticals... where the LC's and the more exotic Microlines/Microridges/FG's are narrower than 0.2mil (some of them as low as 0.1mil, but most around 0.15mil).

[dlaloum]

Just looked up some of my measurements:

TK7su 437/458mH 493/480ohm
AT20SLa 453/453mH 474/477ohm
AT20SLa 453/448mH 489/463ohm
AT14Sa  456/460mH  455/453ohm

These are all clearly the same generator in slightly varying body configurations.
Strangely the TK7su is the worst of the bunch... with a relatively large left/right variation in inductance which causes subtle voicing variance between the two channels.
I would have expected the Signet offering to spec better than the AT offering... but that is not the case.
I have been using an ATN15ss stylus with my best AT20 body... hence AT20ss - I do not own an actual SS body.

[dlaloum]

Measured the X1mkII body...

R= 478  ohm  / 377 mH
L=  494 ohm  / 400 mH

In terms of channel matching, not a great example.... (look at the AT20 in my previous posting!)

Still the channels are within 6% and 3.5% ...

Impedance and Inductance appears identical to the Z1's

[Halcro]

Impedance and Inductance appears identical to the Z1's

What do you conclude from this..?
And how does that conclusion relate to listening experience in your opinion?

[dlaloum]

No conclusion - just data points...

There is enough of a difference between the channels inductance for their to be some channel to channel voicing variation - but the impact is likely to be subtle....

My gut feeling is that the Z1 and X1 generator core are most likely identical with the stylus holder plastic ensuring that the styli are not intechangeable (so as to avoid someone plugging a high end X1 stylus into a low end Z1s)...

Sad to say there is no way of determining whether the core is laminated or not or how laminated (thickness/number) - without destructive testing.... Although come to think of it, I could sacrifice one of my worse exemplars of Z1s...

There is a possibility that the X1 had more sophisticated lamination than the Z1 (similar to Nagaoka and the MP500 vs MP100 )

Meaningful conclusions are what we start to make when most of the measurement is complete....

[neobop]

Just looked up some of my measurements:

TK7su 437/458mH 493/480ohm
AT20SLa 453/453mH 474/477ohm
AT20SLa 453/448mH 489/463ohm
AT14Sa  456/460mH  455/453ohm

These are all clearly the same generator in slightly varying body configurations.
Strangely the TK7su is the worst of the bunch... with a relatively large left/right variation in inductance which causes subtle voicing variance between the two channels.
I would have expected the Signet offering to spec better than the AT offering... but that is not the case.
I have been using an ATN15ss stylus with my best AT20 body... hence AT20ss - I do not own an actual SS body.

The Signet MR5.0ML I recently picked up, also had a disappointing generator, at least channel matching.   I've purchased 30/40 year old ATs and had better luck.

Maybe there's something going on we haven't considered.  Didn't J. Carr say something about laminations making it more likely a cart goes out of spec?

neo

[Grbluen]

No conclusion - just data points...

There is enough of a difference between the channels inductance for their to be some channel to channel voicing variation - but the impact is likely to be subtle....

My gut feeling is that the Z1 and X1 generator core are most likely identical with the stylus holder plastic ensuring that the styli are not intechangeable (so as to avoid someone plugging a high end X1 stylus into a low end Z1s)...

Sad to say there is no way of determining whether the core is laminated or not or how laminated (thickness/number) - without destructive testing.... Although come to think of it, I could sacrifice one of my worse exemplars of Z1s...

There is a possibility that the X1 had more sophisticated lamination than the Z1 (similar to Nagaoka and the MP500 vs MP100 )

Meaningful conclusions are what we start to make when most of the measurement is complete....

I can think of a better use for your worst case exemplars! I know this guy who felt out of place on Raul's thread because he could never find one of the super bodies. Poor guy feels the same way here!

[griffithds]

David,

Quote" My gut feeling is that the Z1 and X1 generator core are most likely identical with the stylus holder plastic ensuring that the styli are not interchangeable (so as to avoid someone plugging a high end X1 stylus into a low end Z1s)..."

I have a Z-1 stylus (original), which is also a Beryllium cantilever with a nude square shank Shibata tip.  It looks and I assume it 'is' the same cantilever/stylus as what is/was found on the X-1.  To my ears, these two cartridges (the X-1 and the Z-1) when fitted with their original stylus assemblies, are identical sounding.  The plastic part of the body has been changed on the Z-1 and also the body of the X-1 which was gold plated is now just bare metal on the Z-1. A few of the published specs. are slightly lower on the Z-1 but even they are well within allowable tolerances of the X-1. Neither of the mentioned changes would effect performance but they both would reduce cost to manufacture.  Perhaps due to mass production, is the reason for the much lower pricing of the Z-1?   I think there has to be some other explanation why JVC chose to change the stylus holders.  Perhaps they too were cheaper to produce in the 'Z'  configuration?  But I do agree that they must be the same generator.
Regards,

[dlaloum]

The Signet MR5.0ML I recently picked up, also had a disappointing generator, at least channel matching.   I've purchased 30/40 year old ATs and had better luck.

Maybe there's something going on we haven't considered.  Didn't J. Carr say something about laminations making it more likely a cart goes out of spec?

neo

The vintage JVC literature states that the Z1 is also laminated. (and that the Z2 body is the same as Z1, the Z3 is apparently a variant originally sold mounted on a headshell)

AT seems to have had their production QC under better control than most manufacturers - with lower variation from spec.

[dlaloum]

I have a Z-1 stylus (original), which is also a Beryllium cantilever with a nude square shank Shibata tip.  It looks and I assume it 'is' the same cantilever/stylus as what is/was found on the X-1.  To my ears, these two cartridges (the X-1 and the Z-1) when fitted with their original stylus assemblies, are identical sounding.  The plastic part of the body has been changed on the Z-1 and also the body of the X-1 which was gold plated is now just bare metal on the Z-1. A few of the published specs. are slightly lower on the Z-1 but even they are well within allowable tolerances of the X-1. Neither of the mentioned changes would effect performance but they both would reduce cost to manufacture.  Perhaps due to mass production, is the reason for the much lower pricing of the Z-1?   I think there has to be some other explanation why JVC chose to change the stylus holders.  Perhaps they too were cheaper to produce in the 'Z'  configuration?  But I do agree that they must be the same generator.
Regards,

Nah - the original Shure patent for their first "stylus holder" (moving away from the M3/M7 type at the time) describes it as "decorative stylus holder" - its purpose always was to interfere with stylus exchange between models!

There are a plethora of examples of high end models being identical to basic models with the stylus being the only differentiator (other than cosmetics): ADC XLM/QLM/VLM, Shure V15HRP/500E, AT120/440, AT14/20, A&RC77/M77/P77, Ortofon OM5/10/20/30/40 and lots more!

In many cases the manufacturer just had a series that shared the styli - in others (like Shure, JVC, AT) variations in stylus and body mounting were designed to stop people swapping styli on otherwise identical bodies.... which is where there are opportunities for the knowledgeable cartridge propeller heards to pick up economy models and equip them with TOTL needles requiring only very minor plastic surgery to fit...

[neobop]

Here's the quote from J. Carr about laminations:
Regarding coil impedance, my general experience is that the fewer the components comprising the coil bobbin, and the fewer the number of coil layers, the more consistent the coil shape and impedance will be. Using more components for the coil bobbin (as in a laminated coil) increases the likelihood of bobbin mis-shaping and non-flat surfaces, while each coil layer added results in a less flat surface for the next coil layer to be wound onto.

 
neo

[dlaloum]

Swings and Roundabouts... like everything in vinyl!

although in this case, I would hazard a guess that laminations increase the complexity and difficulty of manufacture ... and therefore cost, but they do not make the goal impossible...

The AT laminated cartridges of the AT20 family I mentioned earlier are all examples of very high quality manufacturing (and hand picked models from that manufacturing I would think...)

but i also have measured examples of V15V bodies that are disappointing... (Would love to get some measurements from a couple of ultra500 bodies to see whether they were hand picked)

The variability of high output cartridges is one of their downsides, but clearly not a problem that cannot be overcome (you should see the variability of some of the cheaper models!!! - even though they are unlaminated).

Perhaps this is one of the reasons Technics chose to use HotPressedFerrite for their top cores rather than laminations?