[Wayner]

I have thought of doing this for awhile. There seems to be quite a few table/arm combos that just can't seem to reach the Lofgren B alignment, which is my favorite, because it has the lowest "average" % of tracking distortion (but has higher distortion values at beginning and end, opposed to Baerwald).

So I designed a new alignment that is in between the Lofgren B and Baerwald. I've decided to call it the "Baergren" alignment, giving credit to the guys that did all the math.

I did the math for my Techncis SL1200MKII, and here are the particulars:

Pivot to spindle (center to center) distance: 215mm
Overhang: 18.05mm
Inner null point: 68.142mm
Outer null point: 118.672
Offset angle: 23.629°

I have made a 2 point template on a PDF, if I can figure out how to post it, I will at some time shortly.

Wayner

http://www.audiokarma.org/forums/showthread.php?t=511162

post number 8 has a downloadable PDF.

[TONEPUB]

People have been doing this for years, sometimes by accident.

[neobop]

Hi Wayner,
I think Loefgren did the math for both alignments. Baerwald popularized Loefgren A and it became known as Baerwald alignment.
neo

[Wayner]

I know, but the masses know the Lofgren A as the Baerwald alignment, so I took the weak route (not to create controversy) and stuck with the accepted known names. Baerwald was a copycat, me thinks.

Thanks for bring that up.

Wayner

[trackball02]

Wayner, I have a Technics SL-1600 MKII, will your calculations also apply to this model? Thanks.

[Wayner]

If it has a 215mm spindle to tonearm center, hell yes!!!

Wayner

[trackball02]

Wayner, I measured and indeed it is 215 mm. I'm good to go! Thanks.

[Letitroll98]

What, no love for Stevenson?

Seriously, I thought all the older Japanese tables were set up to use Stevenson, one of the reasons they can't get to Lofgren B.  I used Stevenson to align an old Pioneer gift table that I'm restoring, the cart lines up right in the middle of the headshell.

[neobop]

What, no love for Stevenson?

Seriously, I thought all the older Japanese tables were set up to use Stevenson, one of the reasons they can't get to Lofgren B.  I used Stevenson to align an old Pioneer gift table that I'm restoring, the cart lines up right in the middle of the headshell.

Why don't you do what Wayner is doing, use an in between alignment.  Download a straight line protractor at VE and shove the cart all the way to the end of the headshell, then angle it in for an alignment between Stevenson and Loefgren.  That works great.
neo

[Letitroll98]

Uhmm, because Stevenson works really good for old Japanese tables as it is?  And as you are aware, I'm no longer allowed to download anything from that site that will never be mentioned in my posts.   

I don't use Stevenson for my other tables, just tried it on the first Japanese table I've owned in 25 years and it worked perfectly.  I make all of my protractors using Conrad's calculator.  It makes perfect two point arc protractors for any length arm with any alignment and you can set IEC or DIN groove dimensions, use Conrad's suggested ones, or enter your own.  I print them out on thick semigloss photo paper and I get protractors that you could sell for nearly free.  I have dozens of them, so many that I begin to lose track of what's what.  I really don't understand why anyone would use anything else or pay for a protractor, ever.

[Wayner]

I'm not wild about Stevenson's alignment. However, if you are a big Jazz or Classical music fan, that indeed. might be an alignment for you. The first null point is in the label area, which means the longer time LPs will benefit from this alignment and classical records usually fill up both sides of the record. The Stevenson alignment does have a huge tracking distortion percentage at the beginning of the record, but then, that is it.

Wayner

[MaxCast]

So, if Stevenson's alignment has so much distortion, why did these early Japanese tables use it?

I have an early Japanese table (JVC ql-a7, S arm) and notice IGD more so than outer or middle grove distortions. 
Not quite sure what alignment I'm using right now     (I'll have to check) but it was aligned pretty accurately.
Seems like I should be applying an alignment closer to Stevenson's and adjusting anti skate for this region of the lp.

Also, is this true?  If I align to two points on a given alignment, I do not have to be concerned with overhang.

[neobop]

So, if Stevenson's alignment has so much distortion, why did these early Japanese tables use it?

I have an early Japanese table (JVC ql-a7, S arm) and notice IGD more so than outer or middle grove distortions. 
Not quite sure what alignment I'm using right now     (I'll have to check) but it was aligned pretty accurately.
Seems like I should be applying an alignment closer to Stevenson's and adjusting anti skate for this region of the lp.

Also, is this true?  If I align to two points on a given alignment, I do not have to be concerned with overhang.

If you change your alignment your overhang changes with it. 

How do you know the JVC was aligned accurately?

Stevenson minimizes alignment error at the lead out groove where the inner null for that alignment is located. Alignment error is greatest at record center where Loefgren is best, that's why Loefgren has lowest total error.  Baerwald has the most even sound or lowest average error across the entire record.

I think something other than alignment/AS is causing your IGD, although they might be complicating matters. Not enough info to go on, I think the situation will require some hands-on solutions.
neo

[MaxCast]

If you change your alignment your overhang changes with it. 
Right, so am I done with overhang if alignment is set to the protractor I chose?

How do you know the JVC was aligned accurately?
How do you know yours is       As accurately as I can get it with correctly printed VE protractors.  visually inspected for twist.  Would love to get a mirrored one some day.

Stevenson minimizes alignment error at the lead out groove where the inner null for that alignment is located. Alignment error is greatest at record center where Lofgren is best, that's why Lofgren has lowest total error.  Baerwald has the most even sound or lowest average error across the entire record.
Yep,  I understand that and the concept of lp's using up all available space (classical).  I was wondering why TT were manufactured to a highter distorted alignment in the first place.

I think something other than alignment/AS is causing your IGD, although they might be complicating matters. Not enough info to go on, I think the situation will require some hands-on solutions.
I figured that but I'm not done learning and experimenting yet.     I don't believe I have tried the Stevenson alignment yet as I figured lowest ave makes sense to me.  Thanks Neo!!
neo

[Wayner]

Many Japanese tables actually can reach a Lofgren B. Sony PS-X5/X7 series can get to this alignment. My X7 is set-up this way and Frank's X5 is.

To be truthful, I'm not sure back then if they knew about all the alignments. They didn't have the internet to find out stuff at the stroke of a key. Many of those tables also had short spindle to tonearm pivot distances, like the Sony is only 200mm. Perhaps back then, they were also trying to keep the footprint of the table as small as possible too.

I think the golden rule of engineering applies here: All designs are compromises.

Wayner

[watercourse]

Hey Wayner,
Good to see more stuff coming off your plotter.
So, are the distortion characteristics going to be between Lofgren A and B then?
Oh and the reason you'd want to look at a tool like Wayner's is that the layout is a bit easier to work with than other arc protractors, the linework is finer, and most of all they work.

[neobop]

Many Japanese tables actually can reach a Lofgren B. Sony PS-X5/X7 series can get to this alignment. My X7 is set-up this way and Frank's X5 is.

To be truthful, I'm not sure back then if they knew about all the alignments. They didn't have the internet to find out stuff at the stroke of a key. Many of those tables also had short spindle to tonearm pivot distances, like the Sony is only 200mm. Perhaps back then, they were also trying to keep the footprint of the table as small as possible too.

I think the golden rule of engineering applies here: All designs are compromises.

Wayner

Most budget Japanese tables were set up for Stevenson, or close to it, because (I think) they would tend to be used with budget carts which have more problems with inner grooves.  Whether or not you can achieve Loefgren B depends on the headshell slot length/design and the particular cart.  Cart screw to stylus distance varies somewhat.
neo

[raysracing]

Wayner I have yet to sign up for AK, but in the meantime I tried seb's Technics alignment for a 215mm arm, but could not reach the arc due to running out of slot length in the stock headshell. Should I expect to require to buy a new/longer headshell to run your alignment? I believe a store on the other side of town carries longer headshells.

Thanks,
Ray

[Elizabeth]

I have been sticking carts on arms many times.. All i do is guesstimate where it should go.
Never had any problems.
Maybe I should call my method: "Schrodinger's Cat method."
(I do try to line it up good and proper..)

[neobop]

Wayner I have yet to sign up for AK, but in the meantime I tried seb's Technics alignment for a 215mm arm, but could not reach the arc due to running out of slot length in the stock headshell. Should I expect to require to buy a new/longer headshell to run your alignment? I believe a store on the other side of town carries longer headshells.

Thanks,
Ray

Ray,
It's easy to elongate the slots in an aluminum headshell.  You could do it with a little knife or mini file.  You probably only need a couple of mm on the outside slot.  Aluminum is soft and easily worked.
neo