Time to choose: Baerwald, Lofgren, Stevenson ?


I’ve managed Dr.Feickert Analog Protractor for a decent price (build quality is superb, such a great tool).

Time to play with Baerwald, Lofgren, Stevenson alignments on my Luxman PD444.
Need advice from experienced used of the following arms:
Lustre GST 801
Victor UA-7045
Luxman TA-1
Reed 3P "12
Schick "12

Baerwald, Lofgren, Stevenson ? What do you like the most for these arms?
Manufacturers recommend Baerwald mostly. 

Dedicated "7 inch vinyl playback deserve Stevenson alternative, maybe?
Since it's a smaller format than normal "12 or "10 inch vinyl, it's like playin the last track's according to position of grooves on '7 inch (45 rpm) singles. RCA invented this format, i wonder which alignment did they used for radio broadcast studios.   

Thanks

chakster
Dear @lewm : On your take about the Vivid floating tonearm design it's ovbious that you are just speculating about the AS issue.

"""  but the arm gets great reviews and is revered in Japan and Europe.  ""

several people when listen something diferent and especially when the audio item manufacturar touted its " great design " almost always all ( especially reviewers. ) " revered ". Sometimes like in your example is by ignorance sometimes because they like those biased diferences and sometimes those biased differences are no more than higher distortions. In that regards about the " underhung " the design has no real foundation and the manufacturer speaks only on what the listeners heard it but with out single fact on its design and why is " so good ".

Mathematics always helps and you are an advocate to. What happens with the " underhung " higher eror(distortions?

Anyway, maybe all of us have diferent opinions about and maybe no one has the rigth one. That's why exist the so many forums in the internet with so many " hot " discussions. Is part of the audio fun where all we can learn.

Regards and enjoy the music,
R.

Lewm,

When Loefgren published his alignment(s), he equated alignment error to  distortion. I wonder if any attempt has been made to qualify or quantify this assertion,  what kind of distortion and how much?  Aside from a very small amount of phase error between channels (we're talking about rotation of contact area within the groove), it seems to me most error is subtractive and would not qualify as distortion.

With underhung straight pivoting arms, reduction of torsional forces on the cantilever is also said to be a function of no offset angle and skating is reduced to the extent that it becomes unnecessary.

Yamaha offered such an arm as an option on the GT-2000. It is the YSA-2. 


http://www.audiocircle.com/index.php?action=gallery;area=browse;image=122280

Regards,


Raul,

Appropriate to the subject line for this post there are three primary alignments commonly used, identified by the names of the men who developed them.  I jokingly referred to them as the "big 3".

My reason for commenting yesterday was to add to downunder's mention that other alignments have been put forth.  I was not suggesting The Guru method is the best, only that I tried it and found it enjoyable.  I attached a link in case anyone else might be curious to try it as well.

Peace

Lewm & Fleib:

The RS-A1 is a bit different as the cartridge is able to rotate and (possibly) maintain tangency to the groove. In Viv Lab and the Yamaha YSA-2, the cartridge is held straight and thus the cartridge will at the beginning and end of the record be at a ~10 degree angle to the groove.

Some thoughts:

1) The distortion resulting from the stylus being at an horizontal angle to the groove is 2nd harmonic, which I believe is the least harmful distortion.

2) It is not clear to me how different stylus shapes affect the distortion resulting from being at angle to the groove.

3) The calculations only cover horizontal alignment and it’s not obvious to me what the resulting distortions in the vertical part of the stereo signal are and whether these are dependent on the frequency (highly likely) and stylus shape (also highly likely). In particular, it is not clear whether these are 2nd harmonic or something else.

4) This horizontal alignment is the only kind of distortion for which I have seen a calculated estimate. Does anyone know of estimates for the distortion resulting from skating forces or vertical misalignment and whether these are 2nd harmonic or something else? I recall reading a discussion of the design of the Viv Lab where the designers seem to have been concerned about skating forces and considered the related problems worse than those related to horizontal alignment.

5) I’ve only seen one graph claiming to show the actual measured distortion from playing a test record. I came across this on the web and do not know if it is authentic. It was claimed to be from a Yamaha test of their YSA-1 (~Stevenson) and YSA-2 (straight) tonearms. Does anyone know of actual measurements of the distortions?


Sampsa55,

Interesting post. Vertical alignment error (SRA/VTA) can be measured with a test record and a distortion analyzer. I've never done this. It seems to me, it will vary somewhat from record to record and I adjust it by ear and on the fly. Most people hear this as an imbalance -bass to treble which seems more obvious than tonal and harmonic inaccuracies which I also hear.

You say alignment error causes 2nd harmonic distortion. Is this documented? While vertical error is readily heard, horizontal is not so obvious. Adjusting alignment provides clarity and focus. Is this measurable 2nd harmonic distortion? Conventional pivoting arms only have 2 nulls across the record.

It's the movements of the cantilever which trigger the generator. Reduction of torsional forces from anti-skate and offset is said to be responsible for increased clarity. The RS-A1 also addresses vertical torsional forces by aiming the cantilever at the pivot vertically. The rotating headshell seems a compromise between alignment and offset.

There was a Grado Signature Laboratory arm which had elevated pivots and fixed alignment - offset.

Regards,