Stylus Rake Angle


I am trying to set up my new VPI 3D arm as close to perfection as I can. On the Analog Planet, Michael Fremer gives one opinion, however, a different opinion was voiced by Harry at VPI, and Peter at Soundmith. I've been discussing this with them....Fremer says that SRA should be adjusted even if the back end of the arm is WAY high up as needed, whereas Harry, and Peter said to start with the arm in a horizontal position and move it slightly up and down to find the sweet spot. Peter said that my cartridge (Benz LPS) and some others have an additional facet in the diamond so bringing the arm up in back would be exaggerating the proper SRA. When I wrote back to Fremer, he answered with an insistance that he was correct. Does anyone want to add to the confusion??
stringreen
Fear J.Carr: Yes, a few years ago testing Empire cartridges ( I think the 900/1000GT and the 1000 Z/xe. Other cartridges I can't remember. ) I found out that performs the best at " odds " high up cartridge tail/back of tonearm.

I did not tested again since then. But now that you brought here the subject I will try to do it and report my findings. I have to tell you that those VTA/SRA experiences made me to disappear the " afraid " to have that kind of " high up " VTA/SRA. I have to say too that with some today and vintage MM/MI/LOMC cartridge and when I use that high up kind of set up what we can hear from upper mid frequency range and up can be outstanding but unfortunatelly with detriment on the bass management quality performance and perhaps?? higher distortions in the former/that frequency range ( but I do not know for sure because the experience is so different/new. ).

In the other side and know that you asked: I'm just starting to include in my cartridge tests the SRA measure, I'm only waiting for the digital micro arrive.

Btw, I'm with you about try to have a table/chart with all those audiophile experiences with any cartridges where each one report on the SRA measure where we set up the VTA/SRA because was the position that we " like it " and not because it measure that 92 number that as you I still think means almost nothing and certainly is not and is far away to be the industry standard till that can be proved. That chart/table will help to cartridge manufacturers as you are to be " spot on " in the whole subject.

+++++ " For this reason, you should not choose your cartridge alignment (Baerwald, Lofgren, Stevenson, modified versions of these) without considering how close the groove extends toward the label on the LPs that you prefer, and how dynamic and complex the musical content is at the innermost groove positions. " +++++

as almost always there is no perfect alignment ( for several reasons as the one you name it. ): trade-offs always exist and something that helps a lot to lower distortions in the inner LP grooves ( other that the kind of alignment choosed. ) is to choose a cartridge high trcaking abilities and here you cartridge designers/manufacturers are the ones that have the " last word ".

Regards and enjoy the music,
R.
I think 92 degrees SRA as a starting point is better than just setting the arm to level and having no idea what the SRA is. Adjust for best sound after that. You should get more consistent results adjusting between various different carts by starting at 92 degrees.

Even though there is no standard for SRA, 92 degrees seems to be the middle of the range for what records are cut at. To me it would be logical for a cart designer to shoot for 92 degrees when the tonearm is level if possible. That way it is easier to get to whatever SRA sounds best within the adjustability of the arm.

I think it would be a good thing to have a standard but it is probably a little late in the game for that. I wonder if modern reissues are all pretty much the same SRA or are they still all over the map?

As said before in this thread it is not possible to get an accurate reading of SRA using a microscope unless you are lined up perfectly due to the curvature of the optics. How one knows they are lined up perfectly I do not know. I have very good close up vision and trust it more than my results with a USB microscope. My far away vision is another story though. ;)

Sean

Whatever your starting point, level or 92 degrees, the actual SRA arm height range is very, very small! Adjust "on the fly" is worthless, because you will pass over this very narrow peak with a quick adjustment. You must "zero in" over time, to find the optimal spot, and reset azimuth and VTF as you go. Note sonic changes throughout this process, as it is a learning experience.

On my VPI JMW 10 the final sweet spot "window" is plus or minus one index mark on the Micrometer head height tower. This is a range of +/- 3 10,000 of an inch!
Without a micrometer head on your arm, I doubt you will find this optimal SRA spot.

Once I find this "sweet spot point" after listening to many Lp's, over a few weeks or months (after break-in is complete), I do not change the height. 95% of my records are of "normal" thickness, so I do not readjust height for the 180 gm Lp's.

I find I get super playback quality on 80% of my Lp's with this one setting.

One must also take into account recording quality variation, as some Lp's just sound "off" regardless of SRA setting. The resolution of ones system must also be acknowledged for your personal results. Adjusting for each Lp is too "anal retentive" for me!
What? It seems to me your process is far more tedious. Once you've set all other adjustments, it's simply a matter of tuning in the particular record. Similar to tuning a station on the radio. You can hear the sweet spot fade in and out as you tune forward and back. There is no better way. It may be anal if you care that much, but it's certainly not "retentive". If you have not tried this method, it will seriously enlighten you if you do. But you need a tone arm that allows it.
Don_c55, I think what most people are adjusting for with fine VTA adjustment is actually proper overhang. Adjusting VTA will change overhang slightly. IME overhang adjustments make more difference than SRA adjustments. This is just a theory and I have no hard evidence to support it but it is my suspicion. Not to say SRA does not make a difference because it does. I just think fine VTA adjustment has more to do with dialing in overhang than it does with dialing in SRA.

Sean