Tracking error distortion audibility

Hells Bells,

here comes a man that actually makes the stuff (Frank) and tells me what I was arguing for 101 questions and answers with DerTonarm i.e. the spindle-to-pivot distance is not of this ultimate importance to be even close to 0.1 mm according to some geometry decided spec.
You just compensate with the off-set (turn the cart some more left or right) someone must have heard me cry for help.

So now you have it from an arm designer and manufacturer. Very nice Frank, thank you for sharing, time for bed.

Greetings,
Axel

Hi Axel and the rest of the "gang",

Here are the figures relevant for an SME V:

Let's say cart A has a mounting hole to stylus distance of 9,5mm, cart B is unusually "short" and features 6,5mm mh-s distance and finally, we have cart C, the Jaguar E-type of cartridges with 12,5mm mh-s distance

Required for Baerwald alignment(other alignments possible too):

A: 233,15mm eff., offset angle: 23,63°, pivot to spindle distance: 215,35mm, overhang: 17,79mm

B: 230,15mm eff., offset angle: 23,96°, pivot to spindle distance: 212,11mm, overhang: 18,04mm

C: 236,15mm eff., offset angle: 23,31°, pivot to spindle distance: 218,61mm, overhang: 17,55mm

So all that is required is enough slack to rotate the cartridge by little more than 0,3° either way and slide the base forward or backward about 3,5mm, both of which are easily achieved.
Even the "tightest" headshell holes leave enough room and before anyone takes out a reamer to mess with his SME, just reduce(every household needs a small lathe ;-) the diameter of ONE cartridge mounting screw towards the head, leave the bottom part where the thread engages with the cart alone and you have enough leeway for even badly skewed cantilevers(better just send such carts back to the manufacturer).

And many cartridges have cantilevers that are off by more than the above mentioned 0,3°.

Have fun guys...

Frank

Frank,
That suggestion to file down ONE cartridge mounting screw at the top is pure elegance. Simple, effective, and no damage to the arm. Why didn't I think of that? There was enough play in my mounting holes to allow me to rotate my cartridge in the SME V slightly to achieve the proper offset angle according to my protractor.

I'm curious. You mention in your earlier post that an arc-type protractor will not work if effective length has changed. This should not hold true for a protractor that was designed with a specific cartridge and arm in mind, or am I missing something?

You seem to describe perfectly what I have experienced with my SME arm and cartridge. Thank you.

Dear Frank: Welcome a-board.

+++++ " What is the threshold for the audibility of tracing error related distorsions? "+++++

IMHO the " start " subject here is to define/identified first which are and how we hear those related tracing error distortions over the frequency range, certainly we can but is not an easy task especially if we want to define the threshold/limit.

There are some " difficulties/obstacles " other than system quality performance: the wide differences on the velocity recording through the LP, certainly the tracing error related distortions are different at outer grooves than at medium or inner grooves and we have to identified over the whole record, as you point out we have additional " problems " because of stylus shape, different tonearm/cartridge combinations could be more or less " tolerant " about, our ears and know-how level is important too, there is other subject: there are distortions that are incorrect but we like it ( many of us do not like low distortion sound, many people likes higher distortions/colorations. That's why we have to identified the incorrect distortions due to bad geometry tonearm/cartridge set-up. ), etc, etc

Of course that we can do it in a scientific way making measures and then listening till we find for specific grooves the limit to start/begin to hear " distortions " related to tracing error due to bad geometry set-up.

From my mistakes/errors ( like the one I posted elsewhere with the FR702. ) experiences and due that we live in an analog imperfect world it seems to me that that threshold is wider than what we imagine and cmplex to be absolute precise by ear only.

In the mid-time we have to take care on every single step on the tonearm/cartridge rigth and " precise " set-up.

The 90% of what the people ask in this forum, one way or the other, are related with distortions ( everywhere and any kind ) due to an incorrect audio items set-up.
I repeat again, we have to take care on a precise audio link set-up on the audio chain.

Anyway, I know that there are other tonearm designers that are reading this and other related threads, I hope they want and can joint us to share their thoughts and experiences about.

Regards and enjoy the music.
Raul.

Frank,
thank you for all that common sense approach.
I happen to be a trained engineer myself (old school German Mechanics) and I can only agree, that IF you need to get 'anal' about some of these setting, be aware what is 'value added' to improve things, not just for the sake of doing 'something' that might be of little effect in practical terms.

Having said that, in my present experience and so far with two of Ortofon's top MC's --- they have a problem to get their motors in the middle of that sintered body shell. Funny thing, it is hardly, if at all, an issue with their cheaper lines i.e. the Kontra-Punkts. It is to my dismay an issue, that for some unknown reason, with their more expensive Jubilee and PW lines.

What seems a constant here, is the motor being closer toward the left cheek of the body (looking from the front). This creates some, at least for me, more intricate issue since the cantilever is straight as such!
Of course, not being anal about it, just turn the cart a little to the left, if 6:00 o'clock was straight, say to 6:03, and call it a day.

Being now being anal about it, the cart would have to be actually offset at 6:00 to the right, i.e. NOT turned, but shifted toward the right to compensate for the left offset of the motor. The offset is about 0.3 mm and quite noticeable by only looking at it, straight from the front.

In your experience will it be all the same, or actually make a difference in practical terms (in geometry there will be a difference, I say)

Greetings,
Axel