Phew,
thanks for all the various inputs. Never expected THAT much feedback..
To clear up some items and also add some more thoughts.
1) I use a 30dB SUT (XF-1 type M, 1:31.6 xfactor) which is pretty much on the high side for a 0.3 mV cart as is the PW.
2) So far PRIMARY loading gave the best result, it is VERY much different to SECONDARY loading, which I have also tried.
I don't want to go into the detail now, but believe it or not 13 ohms! seems just about a perfect impedance match.
3) With no SUT the loading is anywhere from 500ohm to 47kohm and VERY phono-pre dependent
4) Back to inner groove distortion:
a) The PW allows azimuth alignment 1-3 degree, due to 3 point support. This I long checked with a mirror (as mentioned) it looks fine.
b) the SME's (all of them) come with a SME type overhang adjustment tool --- it appears VERY sensitive and (at least to SME) as accurate, or more, then most any other method.
c) the head-shell is fixed and has a 22 deg. off-set angle (no slotted screw holes) so all seems fine, or?
d) I wish I could have had some better experience with Ortofon. The PW came about due to a Jubilee exchange, a side-wall of the Jubilee splitting open AND a badly misaligned cantilever. The PW seems to be OK regards the housing (new design) BUT has an issue by VERY 'low riding' AND the new 3 point housing needing exceptionaly much higher arm adjustment (the two rear point are to high for the one in front). This makes for a VERY limited VTA adjustment range, with the rear body (tail-end) easily touching the vinyl, when it has a lip (start grooves) or with slightly warped vinyl.
e) Now, using a different cart, Lyra Dorian on 9c Project arm with RPM9 AND LP12 alignment, Baerwald paper alignment tools, etc. ALSO gave me inner groove distortion! --- also with a different phono-pre (PS Audio GCPH).
f) this may help to explain my mentioning Herr Albert Einstein's bit on doing the same thing over and over -- expecting different results :-)
g) As the cart goes it appears to be just riding too low -- when my 3 times repared Jubilee came back from Ortofon, it also sported a higher ride-hight than originaly supplied. Maybe my PW could do with some of that too? But I am sick an tired of Ortofon to be honest.
h) having also tried a Dynavector DV 20X-L, higher compliance than PW and less heavy, I could still make out some but less distortion. Did not fiddle too much with it as it only was a quick test, and this cart is no where near as good/neutral/resolved/etc. etc. as the PW
Maybe it's just all my vinyl...? New Alison Krauss & Union Station "so long so wrong" has ALSO distortion e.g. side two last band --- much too sibilant.
So there you go...
Thank you for careing and greetings
Axel