T4P (P-Mount) cartridges: 20 millimeters? Now THE answer.

[catBot]

I could not find any copies of an official T4P specs edition, so I asked Ortofon's service:

• the distance between the needle tip and the rear flange of the cartridge should be equal to 20 millimeters. Is this distance to be measured under the recomended tracking force or in the "free air"?

The answer is - 20mm without the tracking force.

Now I know what to look for when buying a replacement stylus.

 

[KentTeffeteller]

Add to that 6 grams mass, and 1.25 grams tracking force. Then it's compliant.

 

[lini]

(...) The answer is - 20mm without the tracking force. (...)

That wouldn't really seem to make all too much sense, though - 'cause then the actual needle position during play would be not all too well defined, as it would vary per cartridge/needle design with effective cantilever length, unloaded cantilever angle and (static) vertical compliance.

Hence I'd suggest to take that info from the Ortofon service with a grain of salt, considering that they've provided the one or other false/questionable info before (info about their own products included).

Greetings from Munich!

Manfred / lini

 

[catBot]

Yes, I rather had it under recommended tracking force. Thus it would garantee the proper needle position regardless of the cantilever's length etc.
Less ambigous.

 

[lini]

I really could imagine, that it rather was meant to go for under T4P standard load (1.25 g), 'cause the Matsuhita/Panasonic/Technics guys weren't stupid at that time - and why would they even define, where the centre of gravity of the cartridge should be, but then not properly define another not unimportant parameter? In my view that wouldn't really fit together.

Greetings from Munich!

Manfred / lini

 

[cason]

Well, Technics and Pioneer gauges measure stylus offset without tracking force.

 

[lini]

Well, Technics and Pioneer gauges measure stylus offset without tracking force.

As do the Dual, Philips and Thorens alignment jigs, that I know. But in case of the corresponding turntables models one could always adjust the position a bit, if one would deem that a good idea, or use a protractor instead. Whereas in case of a "native" T4P turntable, that isn't possible - so I would have rather expected a pretty well-defined needle position, especially as the very first T4P models all were linear-trackers (*).

Greetings from Munich!

Manfred / lini


*) I've recently made a little calculation for a post in another thread (see there: https://audiokarma.org/forums/index.php?threads/technics-linear-tracking-tables-and-their-p-mount-cartridges….1069710/post-17381075), and according to that, a (+/-) 0.5 mm deviation in needle position/effective arm length would already cause a tracking error angle of 0.475° at the inner playback radius (= 60.325 mm) in case of a linear-tracker. That's of course still quite a good bit smaller compared to the tracking angle errors, which one would get with a typical radial-tracker at the same position in case of a Baerwald/Loefgren A or, even worse, a Loefgren B alignment (each calculated for RIAA LP playback radii). And at the outer playback radius (= 146.05 mm) it would even be way smaller with not quite 0.2° compared to a typical radial-tracker with any of the usual alignments. But even less of an error would nevertheless still be even nicer - and ca. 0.2 up to ca. 0.5° also are quite a good bit more than the "within +/- 0.1°", that Technics has specified for the SL-10, SL-7 et cetera. And a deviation of (+/-) 0.5 mm would appear pretty possible to me, especially in case of 3rd-party replacement needles.


edit: typo extermination *sigh*