Compromised geometry with sme v


#1

Hi sages

I’m using a borrowed sme v at the mo.

but because my transfiguration cartridge has a shorter stylus to mounting holes distance I don’t know how best to optimise the pivot to spindle distance or cartridge angle (very limited with sme’s holes !

Should i back up the sme on its sled to the standard measurement ? This still has the stylus arc too far towards the pivot of course and in my admittedly weak mind won’t matter too much in the middle tracks but has the angle overly toed towards the inside at the inner grooves and toed out at the lead in grooves ?

I’m experiencing mistracking and even the stylus jumping out the groove on bass heavy tunes. My beloved 7" copy of the Clash’s Bank Robber throws it clean up into the air !

My 12" album version plays just fine and the 7" tracks fine same cartridge in my Zeta.

I could try twisting the cartridge inwards as much as possible as i tighten mounting bolts maybe. But then it’ll be better at the run-in and worse at the run-out ? Or go the other way so I’ve best tracking in the tighter inner grooves ?

Or maybe a pivot to spindle distance somewhere between the two !? my head hurts.

At the moment I’ve got the pivot to spindle distance 2mm millimetres short to put the stylus on the marks of a dr feickert guage.

Anyone with a bigger brain want to help me out here ? I can’t afford a different cartridge at the moment though i would love a lyra one day.


#2

If I have the tip in the standard position (as i currently do) it’ll still be toed out at the lead-in groove and toed out at the run-out.

what to do eh ?


#3

I always liked the Elite Alignment Gauge. It shows you the tracing distortion at different radii, which will help you to understand what is going on with your alignment.

More info here: https://www.analogplanet.com/content/analog-corner-28 (scroll down a bit)

Once you understand the concept you can actually make your own easily enough, or use 1mm graph paper to plot your distortion curve.


#4

Thank you ! for now I’ve just experimented by moving the HTA with the sme’s sled key while playing the troublesome passages (invariably the inner grooves or 7" bass and dynamics heavy tunes)

I’ve got it tracking now at a pivot to spindle distance of 213.5 instead of the 215.3 sme recommend. Unfortunately the sound is generally less compelling and I can’t decide if it’s an improvement or not !

Perhaps I could have the tapped holes in the transfiguration made into slots but I’m nervous about damaging the cantilever or filling it with alloy machining filings


#5

Right, well, this has just
BLOWN MY TINY MIND

So , stylus to mounting holes distance not being 9.5mm , while using an sme IV or V ,
doesn’t matter !??