Feickert analogue protractor....Owners impressions

Excuse me if this is redundant. What about those of us that have an older SME arm that uses the Stevenson geometry? Is it possible to use an arc protractor for these? Aren't most, if not all based on Baerwald? I ask because I just installed a Grado Reference Master on my SME Series III arm. Set the VTA and VTF on a 150 gram LP. Checked and double checked the alignment with a new SME alignment protractor (cardboard, single point). Checked and rechecked VTA/VTF. I notice some sibilence at the beginning of the record. Towards the end, it sounds great. From what I've read, this would make sense due to the Stevenson setup. Is there any way, without changing arms, to more closely "mimic" the Baerwald?

And I agree with Smoffatt, this is a great thread.

Hi 04rdking,

Looking at the specs for the 309 on SME's website:

Effective Length: 232.2
Pivot-Spindle: 213.4
Offset angle: unspecified

From John Ellison's great spreadsheet (free stuff on Enjoy the Music website ... also linked to from my support page):

Baerwaald predicts (for 232.2 effective length)

Effective Length: 232.2
Pivot-Spindle: 214.33
Offset angle: 23.73 degrees

Loefgren predicts:

Effective Length: 232.2
Pivot-Spindle: 213.83
Offset angle: 23.73 degrees

So, assuming your cartridge (stylus position) is consistent with SME's ideal, then your effective length is indeed 232.2. You might try fiddling with the pivot to spindle distance (increasing by about .9mm for Baerwaald and .4mm for Loefgren) to get to Baerwaald and Loefgren approximations.

Perhaps you can lay a piece of masking tape on the base to measure this small change.

If the overall distortion level drops, you can always drop a few coins on either the van den Hul protractor or the TT Basiscs one.

Yip (Mintlp) and I have been positing (not yet verified) that tracing the arc (getting pivot to spindle and effective length right) is more critical than the offset angle.

You certainly won't ruin any records doing this.

Cheers,
Thom

The Ken Willis protractor has provisions for all three geometries (sp?). Right now I have my Audioquest PT-6/Denon DL-160 set up for Stevenson feeling it sounds better than Baerwald. I have not tried Lofgren. I echo the positive comments about this thread. It's the epitome of information sharing without the messianic tone of trying to convert posters as so many threads seem to do.

Thom,
The Series III is a totally different critter than the 309. The specs for the Series III are:

pivot - stylus: 229.0
bedplate center - spindle: 215.4
offset: not specified

Narrod,
Can you give me Ken's contact info?

Ah ... you're talking about the vintage, 3009 then? The same analysis would apply.

Cheers,
Thom @ Galibier