[neobop]

I misunderstood.  From what you said I thought SAS HFR was similar to aluminum.  So, it's 28KHz and damped to 10dB rise:

The next resonance is at 28kHz - and this is relatively undamped - the rise to that resonance is the main thing that needs to be controlled to provide a neutral response... it goes up to over +10db.

The original V15VMR stylus depending on model/variation went from 32kHz to 35kHz (possibly even higher on the Ultra500... ) the tip mass did vary with the very best VST or Ultra versions having lower tip mass - due to thinner cantilever tube walls - the higher spec ones might have been hand picked?

The impact of raising that HF resonance is substantial - the boost on the SAS fades out around 14khz (actually a bit further, around 11kHz - probably due to damping) , where the VN5MR fades out naturally at 16 to 18kHz and with damping influence perhaps down as low as 14 to 15kHz.

How audible is that difference? well, anything below 15kHz is going to be quite audible - and the VN5MR moves the resonance amplitude boost out to above 15khz, then further controlls it with loading (and cartridge inductance) to result in a spec of +/- 1db to 20kHz

I don't entirely understand your explanation.  The boost fades out - you mean the lower end of the boost, and because the VN5MR has higher freq of HFR + more damping, it doesn't augment below 16KHz, and augments less?   This is what I assume you mean and it would imply the SAS is inappropriate as a  replacement for the VN5MR.  Have you tried loading at 10 to 15K w/o such extraordinary capacitance?

This seems like the Peter principle at work.  With the V15V Jico has reached their level of incompetence. 

The High capacitance affects phase in the opposite direction to that generated by HFR, it is sort of like having two treble controls, and turning one up while turning the other down - net effect is Zero (assuming they are calibrated to match each other).

You can model the HFR resonance as an electrical resonance - it has exactly the same behaviour in terms of signal effect both in the amplitude and phase domains.
You can therefore also reverse that effect by building a filter network that has the exact opposite effect - that would be the standard Inductance/Capacitance/Resistance network set up by cartridge with R and C load.

But for the very same reasons that we like to avoid treble / bass controls, ie that there are other distortions added by each stage of processing, is I think applicable here. Yes it returns phase to near neutral, along with amplitude/frequency... but has it in the process boosted other distortions and effectively resulted in a step backwards? - Not sure!

I started looking for the X1 back when I was focused on low inductance bodies.... at the time I had not understood the relationship of phase to cartridge loading and inductance...

But the X1/X2 may also have other benefits, although not obvious in its appearance, it is a magnesium body, most likely potted as well, and in the case of the X2, it specifically states that it has internal anti-resonant treatment.

I think it likely that its performance should be almost identical to the V15V (same or very similar design and inductance) - but the X1/X2 may perform closer to the legendary Ultra500 due to the mounting and shell construction.

Still I am wary of the combination of SAS/and JVC given my experience with the Shure

"The High capacitance affects phase in the opposite direction to that generated by HFR, it is sort of like having two treble controls, and turning one up while turning the other down - net effect is Zero (assuming they are calibrated to match each other)."

"You can model the HFR resonance as an electrical resonance - it has exactly the same behaviour in terms of signal effect both in the amplitude and phase domains."

Wherefore thou utter such conjecture?  You now measure phase, determined the sign thereof and declare peace between domains? 

I suspect the SAS is a better match for the X1, Z1, simply because those carts most likely have a stock cantilever resonance close to that of SAS.
neo


 

[dlaloum]

Have you tried loading at 10 to 15K w/o such extraordinary capacitance?

This seems like the Peter principle at work.  With the V15V Jico has reached their level of incompetence. 

I agree, I am not convinced by the Jico VN5MR-SAS as a replacement for the original VN5MR (and am a fan of the Peter principle!)

I find it interesting that the VN5MR is the only stylus for which Jico have an alternate Boron cantilevered option, the non SAS MR in their catalogue, which is built more like the original Shure in terms of suspension etc...
But I have not tried it, and have not read any reviews of it - the reputation of the SAS has lead to people purchasing only that... also for a long time it was not clear that the VN5MR has a boron cantilever, so it was assumed to be a standard aluminium cantilever and therefore not great value.

It may be the better option for a V15V - but no way of knowing without testing!

Wherefore thou utter such conjecture?  You now measure phase, determined the sign thereof and declare peace between domains? 

I have to admit to building on the knowledge of others - specifically long conversations with Luckydog on VE a few years back.

He provided the physics background and the calculations/formulae for phase/amplitude, and also filled in some blanks about the physics - as long as the phenomena involved are "minimum phase" then you can adjust phase along with amplitude and you can revers them - this is how RIAA works...  The EQ that is applied when recording an LP, affects both frequency and phase, and is in turn reversed by using the appropriate minimum phase reverse EQ filters....

The next question was whether cantilever behaviour was also minimum phase - if it is minimum phase, then its effects can be cancelled out by using minimum phase methods (such as an analogue LCR filter) - if not then other methods would be needed.

It did take a lot of searching and reading, but ultimately I found my answer in research papers on electron microscopy - this is another field that uses needles on the end of cantilevers to measure at the atomic or at least molecular level. Phase effects of the signal received down the cantilever (ie the cantilever motion) is important in getting these measurements right.... and lo and behold the clue I was looking for.... cantilever resonance is MINIMUM PHASE.

OK so now we can put two theoretical pieces together - if cantilever behaviour is minimum phase, then we can reverse it and cancel it out the same way we do with RIAA.... the solution is actually remarkably simple and elegant. (almost freakishly so!)
As long as the filters used are minimum phase such as standard analogue filters or their digital equivalents - achieving a flat frequency response is a result/consequence of getting the phase back to neutral (or vice versa, they go together)

So basically if you can get the frequency response to flat, your phase response will be close to neutral! (like I said - freakishly simple and elegant)

Can I prove it - can I measure phase and demonstrate that this in fact works? - No I do not have the tools for it.
I would have to commission a specific test record with appropriate tracks to test phase..... maybe this will annoy me enough at some stage to try going down this path.

But my discussions with LD (who's non-audiophile career is apparently as a physicist) seem to support this theoretical approach, and my searches for further information on phase/frequency have shown no inconsistencies with this theory.

Some curly other possibilities - there are other influences on the frequency response - eddy currents, cantilever flex, etc... other causes for non-linearity and other causes of distortion that may appear within a F/R measurement plot.

Of these effects, those that are simple resonances AND minimum phase are no concern - that corrects out simply by achieving flat F/R. But some of these effects are not simple resonances, and therefore cannot be corrected for in this manner (bummer).

So you need to find a cartridge/stylus that minimises effects other than basic resonances to be able to correct phase truly and effectively using these methods.

It is very hard to separate out these other influences from the resonance - I think I may be able to estimate the eddy current contribution to losses in high frequency - but it is a gut feel based on some observations/measurements and I still need to research the maths further before I can test it and try to apply it to my model - and then try to measure it to confirm whether reality conforms with the hypothesis....
Eddy current is probably the biggest additional influence. But I won't know until I work through how to measure/calculate it etc...

This bit is a work in progress. but I am fairly certain that within the 1kHz to 8kHz zone it is not more than a 3db contribution to losses - above that it gets harder as the cantilever resonances kick in and make it hard to determine what is the EC loss and what is the resonant boost. (hence the need for a theoretical mathematical basis that I could then use to separate the two....)

All of which amounts to saying - it is not conjecture but well documented physics.

However my mental and mathematical cartridge model is still incomplete, and the devil is in the detail.

I suspect the SAS is a better match for the X1, Z1, simply because those carts most likely have a stock cantilever resonance close to that of SAS.

It may well be! - but it would require that both the resonance AND the damping be close to that of the SAS - which would be a remarkably serendipitous circumstance.

On the other hand, I believe that this is exactly the case for the V15III and IV - where the SAS specs seem coincidentally (or perhaps by design?) very close to the OEM styli. I believe the SAS was first released for the V15III - perhaps because this is a very common cartridge that sold in huge numbers, so maybe the match is no coincidence.

In any case I am looking forwards to Don's review, and then to getting my hands on an X2 (or is that X1mkII.... some sources use one name and some the other, yet the photos seem to show the same cartridge..)

bye for now

David

[neobop]

I figured Luckydog provided the basis of this, and I suspected a similar finding, but.....

" if cantilever behaviour is minimum phase, then we can reverse it and cancel it out the same way we do with RIAA.... the solution is actually remarkably simple and elegant. (almost freakishly so!)
As long as the filters used are minimum phase such as standard analogue filters or their digital equivalents - achieving a flat frequency response is a result/consequence of getting the phase back to neutral (or vice versa, they go together)

So basically if you can get the frequency response to flat, your phase response will be close to neutral! (like I said - freakishly simple and elegant)"

The problem here is an RIAA reverse filter is set within the preamp to compensate at fixed frequencies and at predetermined slope.  It just becomes an exercise of selecting the right caps and testing for accuracy.  It's more complex with cantilever resonance, electrical resonance and phase.   There are instances within a response plot where amplitude and phase are going in opposite directions and then the same direction within the scope of an amplitude compensation filter.  In reality you're not doing anything to cantilever resonances, you're manipulating electrical parameters to interact, because the net amplitude response is mechanical + electrical. 

If you have a cart of 320mH, and load it with 720pF, electrical resonance is 10.5KHz.  This doesn't change mechanical HFR.  The cantilever wiggles are what they are.  A tuning fork doesn't change pitch, but you could manipulate an electrical output to do so.  There's a 180° shift either at mechanical or the combined resonance (mechanical I think).   Does loading with capacitance cancel this?  It lowers in frequency the net affect, like maintaining 250pF on an M97 so treble droop doesn't worsen.  What's the HF response look like at 720pF, still response past 20K ?

Seems to me you'd be better off using Scotty's X-induct in reverse.  Hook up 200mH coils in series.  I wonder how much a used accelerometer costs?
neo 

[neobop]

In that 1977 Popular Mechanics survey of 4-ch carts, they said the B&O 6000 was the clear standout.  These require a mounting adaptor for standard 1/2" mounting.  I've seen these on epay and they might be available from Soundsmith.  I believe they used an adaptor in the magazine survey so it might not be too bad.  Other than that, I have no info about this adaptor or how it might compare to a P-mount to 1/2" adaptor.

I saw this ad on US Audio Mart for a NOS MMC2:
http://www.usaudiomart.com/details/649141968-new-in-box-bang-amp-olufsen-mmc-2-pickup/

Nice little chart in the ad:



The MMC 6000 has a beryllium cantilever and a tip they called Pramanik - probably like a shibata.   VTF = 1g, cu = 30. 

neo

[neobop]

Did you know Stanton had 3 LOMM models?

Product catalogue from the Library of Congress.  Specs on last page.
http://lcweb2.loc.gov/master/mbrs/recording_preservation/manuals/Stanton%20Product%20Catalog.pdf

neo

[dlaloum]

And there were the pickering versions as well - including p-mount...

p.s. I contacted pickering UK, they still have the LO p-mount bodies in stock new, but no needles - however they wanted too much for it! (I would dearly like a p-mount version for the Revox, but not at the price they are asking...)

[neobop]

David,
V15 RS ?  Specs look like a V15VxMR except w/HE stylus.
So that would be SAS @ 27K/700pF  or regular replacement:
http://www.turntableneedles.com/Shure-VN5xMR-type-JICO-Brand-HyperElliptical-Stylus-our-Needle-77x3-DHE_p_4183.html

http://www.turntableneedles.com/VN5xMR-type-JICO-Shibata-Stylus-for-Shure-V15xMR--our-Needle-77x3-DSH_p_4120.html

SAS:
http://www.lpgear.com/product/e007496.html

http://stylus.export-japan.com/index.php?cPath=18&sort=2a&page=12

Hi
over the weekend i pick up a realistic V15 RS but it need a new stylus which one do u recommend?
Thanks
lap

[dlaloum]

With the V15RS, it is identical to the V15VxMR, just like Neo said.

Best needle is the VN5xMR-SAS from Jico - I have not done the extensive testing with my own RS & SAS to identify the optimal loading, but at a guess I would place it in the mid 30's for R and maybe 500pf - the body is 420mH from memory - so you have a bit more inductance to help out...

I would experiment with values from 32k to 42k and from 450pf to 600pf.

An alternative would be Jico's VN5MR (non SAS) which also has the boron cantilever and MR needle, but with the original Shure style suspension and not the proprietary Jico SAS suspension - it is slightly more economical, but I have not heard it or tested it, nor have I read any reviews of it in the forums.... 
I can hazard no guess as to its loading... assuming it has a lower res F you would need to raise the C... but  until measured - who knows?!

[neobop]

Stocking Stuffers - might be post Xmas stuffers by the time you get it, but don't you deserve another toy?

http://app.audiogon.com/listings/cartridges-grace-f-9e-rare-top-mm-cartridge-2014-12-20-analog-90066-los-angeles-ca
Is this the same guy as before?  There's also a 9L for the same price.

http://app.audiogon.com/listings/cartridges-signet-7-tkcla-2014-12-18-analog-15241-upper-saint-clai-pa
Replacement stylus is now unobtainium. SS charges $450 for a micro retip.  Maybe Andy Kim or Expert Stylus is more affordable.

Here's a new one on me.  Anyone hear of it?
http://app.audiogon.com/listings/cartridges-synergistic-research-pht-phono-transducer-free-shipping-worldwide-2014-12-12-analog-92307-apple-valley-ca

http://www.usaudiomart.com/details/649166359-ortofon-kontrapunkt-b-mc-cartridge-ruby-cantilever-mint-condition-low-hours/
Maybe out of the realm of stocking stuffer.  Lots of love for the B.

http://www.usaudiomart.com/details/649165832-audio-technica-at14sa-mm-cartridge-stylus-oemnos-atn14/
Sweet

http://www.usaudiomart.com/details/649161505-audiotechnica-at20sla-phono-cartridge-lengendary/

http://www.usaudiomart.com/details/649109584-shure_premier_m95ed_cartridge_with_new_evg_stylus/
Is this a good deal on this cart? 

neo

[neobop]

7 reviews from 1980 - Dynevector Karat Diamond and Ruby
http://www.cieri.net/Documenti/Cataloghi/Altri%20marchi/Dynavector%20-%20Moving%20Coil%20Cartridge%20Test%20Reports%20and%20Reviews.pdf

neo

[neobop]

Popular Electronics - test report  7/'73  Shure V15 III
http://www.americanradiohistory.com/Archive-Poptronics/70s/1973/Poptronics-1973-07.pdf

Page 76  check out capacitance.

neo

[a.wayne]

AT95 sa ....?

[neobop]

AT95 sa ....?

Hi A Wayne,
That's an AT95 w/Jico shibata

neo

[neobop]

Saw a thread on VE about putting an AT95 into an aluminum body:
http://www.vinylengine.com/turntable_forum/viewtopic.php?f=19&t=73915

I assume they mean a deluxe aluminum body, it already is aluminum.   Seems to be a lot of trouble unless the goal is have a different plug.  If someone wants to go there, I think complete potting could be worthwhile.   Mine is partially potted and it seems to make a difference.  I suspect a nice ebony top would be an improvement for virtually any AT MM, and would be more worthwhile. 
BTW, stock stylus 10Hz cu = 15.

On another note I'm a little surprised we haven't heard more about the JVC X1, Z1.  Maybe it's because almost nobody has an X1 ?  Comrades Nandric  and Griffithds have declared it the best (Agon thread), but no one else concurs?  David?

neo

[griffithds]

Hello Neo,

I also am waiting to hear from David.  I do have more to say in regards to the Z-1 SAS combination but I want to wait and hear from David before I add to the discussion.  I just saw a JVC Z-1 EB purported to be an elliptical/boron combination on the Jauce (Japanese auction site), sell for $27.  I seriously thought about bidding on it but considering I already own 2 of the X-1's and a Z-1 original with also a SAS stylus to place in it when ever I want, sort of makes me feel  I'm might be getting greedy so I left it for someone else to discover. 
I stand by my claim BTW! And I am also sure that Nandric has the same problem that I have (when one of them is in play), in regards to getting this smile off of our faces!  (grin)
In play I hear very little difference (if any), between the Z-1 and the X-1, both having a beryllium cantilever and a shibata tip. There is a slight difference in measured responses but where it counts the most, between my 2 ears, I do not hear it.   
I was able to buy a Z-1 original stylus (beryllium/shibata), from that Jauce site for $22.  Yes, pocket change for a beryllium cantilever!
But the real killer deal is with the Z-1S body (which can be found on any auction site), married to a Jico SAS stylus.  More details will follow after David has time to digest his X-1 MKII and reports! He has waited for a long time to get a X-1 body to go with his original stylus so I want him to enjoy it first.
Regards,
Don

[dlaloum]

Hi Don,

The X1 arrived two days ago, I will report when I get the chance...

[neobop]

Hello Neo,

I also am waiting to hear from David.  I do have more to say in regards to the Z-1 SAS combination but I want to wait and hear from David before I add to the discussion.  I just saw a JVC Z-1 EB purported to be an elliptical/boron combination on the Jauce (Japanese auction site), sell for $27.  I seriously thought about bidding on it but considering I already own 2 of the X-1's and a Z-1 original with also a SAS stylus to place in it when ever I want, sort of makes me feel  I'm might be getting greedy so I left it for someone else to discover. 
I stand by my claim BTW! And I am also sure that Nandric has the same problem that I have (when one of them is in play), in regards to getting this smile off of our faces!  (grin)
In play I hear very little difference (if any), between the Z-1 and the X-1, both having a beryllium cantilever and a shibata tip. There is a slight difference in measured responses but where it counts the most, between my 2 ears, I do not hear it.   
I was able to buy a Z-1 original stylus (beryllium/shibata), from that Jauce site for $22.  Yes, pocket change for a beryllium cantilever!
But the real killer deal is with the Z-1S body (which can be found on any auction site), married to a Jico SAS stylus.  More details will follow after David has time to digest his X-1 MKII and reports! He has waited for a long time to get a X-1 body to go with his original stylus so I want him to enjoy it first.
Regards,
Don

Hi Griff,
Seems like a prudent move, waiting for David.  I don't doubt your sincerity, but we all have different opinions and so far it's you and your comrade saying it's the best MM.  I think Aceman said it was sweet.  I don't know what Raul said, apparently it never made it to cart of the month even though he used 100K load - same as 4-ch. 

Considering the carts have response to 40 or 60KHz (whatever), I see potential problems with an SAS and its low resonant frequency, but who knows maybe it's like a 95/CA (400mH range) - throw just about anything on there and it sounds different degrees of good.  I believe David has an original stylus so probably no report on a Z1/SAS.  These things are never all or nothing.  Like the TK7LCa, some people love it and others think it's second tier.
neo

 



 

[dlaloum]

No SAS for the X1 here.... (hesitant to get a 4th SAS when my other 3 are barely run in!)

And the TK7LCa, well it is basically an AT20ss isn't it - and I have to say the AT20ss is pretty spectacular...

[Grbluen]

Could someone give me a "heads up"on one of these bodies?
Don grb

[neobop]

No SAS for the X1 here.... (hesitant to get a 4th SAS when my other 3 are barely run in!)

And the TK7LCa, well it is basically an AT20ss isn't it - and I have to say the AT20ss is pretty spectacular...

I agree, the 20SS is a great cart, but it doesn't have colorations some prefer.  There are so many ATs over the years it's hard to keep the numbers straight.  The 20SS is 2.7mV, 500 ohms - response to 50K.  The 7LCa is 5mV, 800 ohms DC, 550mH - response to 35K. 



The 7LCa is slightly sweeter, more seductive, while retaining good resolution.  IMO the 20SS gets its sweetness from the shibata and is a little more neutral, transparent, and slightly more resolving.  Both great carts.
neo