Uni-Protractor Set tonearm alignment


Looks like Dertonarm has put his money where his mouth is and designed the ultimate universal alignment tractor.

Early days, It would be great to hear from someone who has used it and compared to Mint, Feikert etc.

Given its high price, it will need to justify its superiority against all others. It does look in another league compared to those other alignemt devices

http://www.audiogon.com/cgi-bin/cls.pl?anlgtnrm&1303145487&/Uni-Protractor-Set-tonearm-ali
downunder
Dear Daniel, it is my fault not to be clear about this. My LPs are all from '70s and I don't have but a few classical symphonic music so, I prefer the Loefgren B IEC, all the time.
Dear Geoch, it is an important feature, but it is only one important feature among a good half dozen others.
Knife-edge bearings do have a good bundle of problems too.
Some of them are quite severe and do limit the performance of a knife-edge tonearm - that's why I personally abandoned the knife-edge bearing pretty early in the development of my design.
Low friction isn't everything (in fact - it is negligible in all better tonearm bearings today).
You should address this topic in a separate thread and I can assure you that you will get many posts and comments by some of the more active A'goners as well as by some tonearm designers.
Please do start that thread.
Cheers,
D.
Dear Daniel,
Interesting comments on arms with knife-edge bearings?
The SAEC arms with double knife-edge bearings enjoy quite an enviable reputation amongst the 'vintage' fraternity with Thuchan even ranking the 12" versions competitive with the FR series tonearms?

I wonder if you might expand on the weaknesses you find in this solution.......especially since I have a new addition to my arm collection arriving shortly.......namely an SAEC WE-308?
Cheers
Henry
Dear Raul,
understand very well. maybe we all have spent a little too much in too many different solutions regarding finding the exact geometry for our tonearms. I became happy with the Dennessen but did also see the limits for other installations when getting to know that some data inputs from some manufacturers for their own arms were not the right ones for special cartridges we are using. Therefore the situation for someone who deals with more than one tonearm/cart was calling for a universal approach. I have big hopes that the Uni-Pro is a good answer for those multi-users but I also wait with an assessment until I have made my own experiences with the sets ordered.
Dear Henry, knife-edge bearing tonearms do not like cartridges which do transfer a lot of energy into the armwand. Thus SAEC tonearms - despite the fact that some do sport a pretty high moving mass - in general do fare better with cartridge featuring high compliance.
So expect your WE-308 to perform pretty well with most of your MMs, but not with a FR-7.
As I still do favor LOMC and some with really low compliance, the not optimal energy handling abilities of the knife-edge bearings were abandoned in an early design stage.
To achieved my goals I needed very hard and rigid bearings and an armwand which can transfer energy ASAP without torsion or inner resonance.
Cheers,
D.