Uni-Protractor Set tonearm alignment

Hi Dertonarm,

will there be an individual template for the Raven 10.5 tonearm? Otoh, a Löfgren B template is provided with the Uni-Protractor...

Thank you.
Blam!

I've heard about the special alignment that Derto suggest for FR64S and now ... the Phantom requires another one !

Can someone please explain to me about :
"the specific geometry" of an arm ?
What are the individual parameters ?

In my case, I've just bought the SAEC WE-308 SX .
The first thing that you can see, is the insanely small Offset Angle : 11.984 (the Eff. Length is only : 9.448")!!!
I've search & copy from the VA :
"This arm was the result of research by Sansui Co. to determine the optimum pivot position from a kinematic point of view, with the mass of the arm, the location of the center of gravity and the moment of inertia around the system's center of gravity taken into account to solve the problem of resonance. It is designed for dynamic balancing across multiple axes of rotation for stability against resonances. Any change in the arm geometry will change the resonance of the system "
The recommended by SAEC Overhang (for it's 240mm Eff. Length) is only 5mm
The IEC Baerwald equivalent for 240mm Eff. Length is 17.241
The difference between the Pivot recom. by SAEC (235mm) & the Pivot that resulting by the IEC Baerwald alignment (222.76mm) is huge !
The guys who tried the SAEC suggestion they confused so much with the distorted performance, that are convinced for this was the reason why SAEC arms did not make a success in their times. So, they rotate the cartridge on the headshell by another 10.93` to find the right Offset Angle of 22.914` and then they proceed by the IEC B alignment.
Why they choose the Baerwald ?
Is is wise to give a chance to every other known alignment geometry ?
How can any one determine the right method of alignment for a tonearm, IF the Offset Angle does not match with any known geometry ?
Can you advise specifically about my WE-308 SX ?

Thank you.

Dear Geoch, hardly any of the japanese tonearm designs of the 1970ies or 1980ies had Baerwald IEC calculation curve in mind. People look up Baerwald IEC distortion curve readings on VE and since they deliver the lowest reading at the 3 distortion peaks, some do automatically conclude this is the best for every tonearm.
It is not - for obvious reasons.
For your SAEC 308 SX may I suggest you try Löfgren B DIN instead.
It will give you much better sonic results, as the SAEX's geometry matches far better with Löfgren B DIN or Stevenson.
Baerwald IEC is great for most modern 9" tonearms AND when playing mostly modern records cut with a long lead-out groove (i.e. the area on the record actually engraved with recorded sound is rather small ).
If you have a tonearm with an effective length anywhere between standard 9" and 12" (which applies to most today) AND/OR are playing mostly older records from the late 1950ies to mid/late 1970ies with rather small and short run-out groove (i.e. cut close to the inner label ) then Baerwald IEC will inevitably result in high distortion figures in the last minutes of each record sides.
There is no free lunch here.
We have a large variety of different pivot tonearm designs which not only differ in their design apparent to the eye, but also in their geometrical design.
If you get a reading of less than 10 mm in overhang for a 10" tonearm (SAEC 308 SX), then the geometry in question is wrong for that particular tonearm.
I do not want to go into any more length about this ( I have done so intensely in the past and really dived into this topic till I reached solid rock....), but let me suggest you try Löfgren B DIN or Stevenson DIN and come back to us with your findings.
Cheers,
D.

Hi Blammy, no customer request so far for a special Raven template. And yes, the Löfgren B is readily availalble for both DIN and IEC ...;-) ...
Thank you,
D.

Dear Geoch, I have good news and bad news reg.SAEC.
The good news is that you can download the user manual for
the WE-308 NEW from Vinyl engine. The bad news is that there is no mention of the zero points by the specifications. I wrote there 61/89 but have no idea where I got this info from.
Your quote from the VA is probable from Kessler& Pisha;
Tonearm Geometry and Setup (Audio, January 1980). They
suggest to use SAEC geometry and setup. If I am well informed ony the WE-407/23 allows 'the usual' geometry (aka
Baerwald).

Regards,