STD 305M with SME Series 3 Arm, Need Protractor

[Joe Dawson]

I am trying to setup my turntable, but which protractor to use?

I have an STD 305M and an SME series 3 tonearm.
Attached is a photo of an STD M with an SME series 3 arm, both just
like mine.

I have two protractors, one an SME and the other is a "cart align",
and each is so far off that mounting the arm base would require me
to glue the arm base rather than the normal mounting.

Need help in finding the correct protractor to mount the arm.

Thanks for time and help.

 

[Blue Shadow]

The 'correct' protractor doesn't exist. The pivoted arm crosses the record in an arc and is only holding the cartridge perpendicular to the groove at 2 spots.

Different alignments, Stevenson, Lofgren, and Baerwald position those 2 spots at different places across the grooved record to achieve different results.

Stevenson has one at record end for best end of record accuracy.

Lofgren, there are 2 of these, Lofgren A which is also called Baerwald selects two spots so that the maximum error at end of record is equal to center of record (between the two zero error spots) and also equal to beginning of record. Or something like that.

The Lofgren B is another choice.

See vinylengine tools section for alignment protractors and look over the info on that page and linked pages for a better understanding.

I use the manufacturer recommended Baerwald alignment on my Magnepan tonearms. Try a couple and use what you like. VE might have a protractor for the SME III in the library avail for download.

I've written about it a number of times and others have comments, too, correcting a statement in one discussion. I found this one https://audiokarma.org/forums/index.php?threads/sme-3009-s2-imp-correct-alignment.992715/ searching Steveson and Blue Shadow as the author. There are more if you want to read while you wait for more responses. Folks like ConradH's alignment protractor available from his site It should be mentioned in some of those discussions.

 

[kbwhaaland]

Stolen from Vinyl Engine:
The original "older" SME III had null points at 60.0/117.0 (Stevenson geometry) while the "newer" carry arm, CA1, has nulls at 66.1/120.7 (Baerwald).
To clarify, if your arm wand has 2 holes between the cartridge mounting bolts, it needs to be aligned to Stevenson geometry. If there is 1 hole, it is Baerwald.

Distance from the centre of the oval mounting hole to the spindle should be 215.4 mm, but there is +/- 12,7 mm wiggle room of the oval is inline with the spindle.

Stevenson for this one.

 

[totem]

each is so far off that mounting the arm base would require me
to glue the arm base rather than the normal mounting.

Something is definitely off when the SME supplied alignment card will not reach,
You are moving the base forward and back using its geared travel?

 

[Joe Dawson]

Thanks for the input Gentlemen.
Below are some photos of the SME protractor, SME base on top of my TT in order to make the amp "match" the purchased protractor,
and the bottom undercarriage to show the position of the SME base.

My head shell has two holes between the cartridge mounting holes.Right now, the spindle
to arm pivot seems to measure about 210mm.

The base is as far forward as possible using the geared travel. The undercarriage
photo shows the base as far forward as possible, butting against the steel brace,
but still within the manufacturer's cutout.

What is interesting to me is that the cartridge appears perpendicular to the grooves
across the LP. Could it still be better? Sounds like it could from your comments.
Appreciate that.

More comments welcome.

pos

 

[Blue Shadow]

The arm should have travel for its entire range in the SME specified cutout.
You can check the cutout using the SME mounting template to verify that the cutout is positioned properly and not pushed back due to tt structural interference. If the cutout is not where it should be, we need to go to plan 9 from outer space.

I find the need to move the arm to the very front of the cutout for a number of cartridge mountings. This on a 3009/S2 Imp and expect the same with the 3009 Series III.

How far off is the cartridge from parallel to the lines on the protractor?

 

[Joe Dawson]

Hi Blue Shadow,

I forgot to respond, that I understand how a cartridge/arc works. I Much appreciate your comments Blue Shadow.
I must apologize to everyone that I did not remember that I purchased and used the SME Series lll protractor.
I completely forgot, my memory is not good since I was rear ended some time ago.

Yes, I can move the arm its entire range in the cutout. I have it adjusted for the maximum front position in the cutout.

The cartridge is almost perfectly in parallel to the protractor lines. If it is off, I am thinking
maybe 1 degree? Not much. Is that ok or need closer?

Thanks again gents for helping me.

keep on truckin

joe

 

[Nat]

My memory is that there were two different wand lengths for that arm, and I think they may have changed the alignment used on each. So you might be using the wrong protractor.
With arms that have slots in the headshell, you can change the angle of the cartridge to make up for mismatches, but the SME is much less flexible in that way.
I love the arm - it is what I use, but when I change cartridges, and, usually, wands, there is a lot of headscratching.
And the arm board - can it be reversed? That might allow a different set of limits to motion.

 

[Blue Shadow]

If you get an alignment right, it doesn't matter which one you use, you will get the benefits of that alignment.

 

[Nat]

That is true, but, because you can't change cartridge angle in the SME - the headshell has holes not slots for the screws - you can't necessarily get the alignment right if you use a different protractor. And the OP posted because he was concerned that he might not have it right, even at the far extreme of the adjustment range.

 

[Joe Dawson]

I see the SME website still lists the one I have (for SME series lll) as the correct one. It is shown in a previous post.
Thinking about it, the arc will just be altered or skewed towards more or less distortion across the board, beginning, or
ending of the LP. Am I correct with that analysis?

keep on truckin

joe

 

[kbwhaaland]

It doesn’t say which of the two possible alignments for a Series III it is for.
If my first answer was unclear: Yours has the Stevenson nulls. Any two-point Stevenson protractor will help you get the alignment right.

 

[Nat]

Depends on which wand he has -I don't think there is an older or newer SME III, instead it is the different wands available. The original wand turned out not to have enough room behind the mounting holes for some cartridges (a problem I encountered) so they came out with a wand with a deeper headshell. I also think that they came out with a longer wand which had a different alignment. If memory serves it was the black one.
And,even though the alignment range is restricted if the mount is parallel to the side of the table, many table only allow that - the STD being one. So he may not have enough room for some alignments.

 

[totem]

Spindle to pivot on the OP's 2 hole "early" arm wand is 215.34 mm
*later single hole wand is 215.4

If the table structure is not restricting travel that leaves incorrect
mounting position of the SME base itself.

 

[Joe Dawson]

As I mentioned earlier, the headshell has two holes, so original. With the SME lll
protractor, I have reached the forward limit of travel, both in the cut out, and
gear travel of the arm on the base. So there is nothing to adjust forward.

I shall look for the stevenson (vinyl engine) and download and see if I can back off
from the front mount. If so, good. If not, I would have to extend the cut out and rid of a
brace in the way (see undercarriage photo above), which I really don't wish to do.

I will check for the stevenson protractor.

Thanks for the help Gents.

keep on truckin

joe

Update:

I just downloaded the stevenson protractor from here:
https://www.vinylengine.com/cartridge-alignment-protractors.shtml

Printed, measures 180mm from A to A', so scale is correct. Holes made.

What a difference between the SME lll protractor settings (photo top of page)
and the Stevenson.

I have moved the SME arm base as far back as the gears will allow me, and
the arm is still major different/off according to Stevenson protractor. Attached
are photos at the critical points.

I measured from the spindle center to the SME pivot point using a wire
(I made it as straight as I could.). It measured 220mm. That is to the side
of the SME shaft, and the wire has a slight bow in it, so not super accurate.

What do you gents think?

 

[kbwhaaland]

I see no needle in the pictures.

 

[totem]

mounting position of the SME base itself.

Just to be clear the above is in reference to where the SME cutout was made in the plinth.

 

[Joe Dawson]

Attached is an undercarriage photo showing the black plate placed within a thin cutout of the aluminum colored plinth.
(Right now, the needle is pretty close to the cartridge sides. I am not worried about that right now, just the cartridge.)

The tonearm base is as far back as possible. I do not think I could move the SME closer to the TT
platter though.

keep on truckin
joe

 

[Joe Dawson]

After moving the arm fully back via base gears via stevenson protractor, and re checking with the SME protractor,
mentally calculating, it appears to me that the tracking error near the LP spindal is worse than
if I just used the SME as the proper protractor. In otherwards, it appears to me that the arm should
be as far forward as possible.

Is my thinking correct, or am I off in that assessment?

keep on truckin
joe

 

[technome]

Here is a photo of my old STD 305M with the SME Series III. This is how it should look when it is properly aligned.



The close-up photos you are posting aren’t helping us identify the problem.

Please post a photo showing your whole turntable with the protractor set with the stylus on its correct point.

We might be able to see what the issue is.