Adjusting SRA using macro lens vs microscope

Agree with Dan. The system had few commonalities with ours, so whatever anomalies Paul and I noticed might have been attributable to many things.

FWIW, the A90 is one of a very few cartridges I've used that has as narrow a range for VTF, SRA and azimuth as a UNIverse. It is very easy to set up sub-optimally. As with a UNIverse, that results in sub-optimal performance and could cause one to mis-judge the A90's capabilities.

We found it easy to hear when SRA or VTF were "off" and easy to decide which way to go. That suggests a nicely linear design. A cartridge that's unclear about which direction is right may end up sonically flawed even when optimized. The A90 was admirably clear.

Apologies to Glai for the thread-jacking.

Doug and anyone else who might know, do you think it was ever thus with cartridges? I mean to ask whether it has long been a custom in the industry to set the cantilever/stylus angle such that by leveling the top surface of the cartridge body with respect to the platter, one is in the correct "ballpark" for SRA. I and many others have been messing about with vintage MM and MI cartridges, per Raul's endless thread, and many of us find that many of these cartridges sound best with more than a bit of "positive VTA", meaning that the tonearm pivot is raised with respect to the cartridge body, for best sonics. We are talking here about many cartridges that were very high end in their day. This phenomenon could in part be due to aging of the cantilever suspension, such that it has less flex than originally intended, but maybe not.

Thanks guys!

Lew,

I don't have experience with enough MM's/MI's on rigs with adjustable arm height to generalize. I own one decent MM and tried a friend's MI for a spell, but that's about it.

Your speculation that stiffening of the suspension may explain why some of them prefer a "positive VTA/nose down" attitude makes perfect sense of course. From curiosity, how do these cartridges' sonics change when you play them this way vs. level?

@Dougdeacon

The cutter head is consistently set at 92 degrees on almost ever record cut. The proper SRA will yield excellent play back on 80% of all records. Best results only will be obtained with an MC cartridge on Panels (Magnepan) or electrostatic speakers IMHO.