How to set SRA after determining true vertical?

Hi all,

Doug, I do remember that the arm tube seemed a bit low at the pivot but that could have been the angle at which I was viewing it. I've come to learn not to worry so much about arm orientation thanks to threads such as this.

What most impressed me was how you could make a quick adjustment to the TriPlanar and Paul would either nod, winch or shrug. (He did a lot of shrugging with my rock music. :) Paul practically called me a head banger! I think of myself as more of a head banger with finesse, thank yew very much!) Based on my experiences with suspended tables, I swear there were times when my heart would skip a beat watching you quickly, and seemingly without care, beat about the pivot while adjusting VTA. (Not really, Doug is very graceful.)

Andrew, I see where you're going and I'm inclined to agree. IF the armtube angle is based on SRA then, as Neil has shown, changes in the arm angle do directly affect SRA. Perhaps it is picky, but it is important to realize that in the end it is the SRA that makes the difference.

SirSpeedy, if you start using remotes for everything I can promise you'll end up with a bigger spread than mine. Sorry I'm not going to catch up with all of you at VTV. Maybe sometime soon!

SRA is irrelavent. It is the position of the stylus in the groove that counts. The maufacturer designed the cartrridge to achieve that with the arm parrallel to the record surface. To the extent you use different forces and angles you may have to raise or lower the arme to restablish that angle.

If you read Mr. vdH's notes (the Q and A part) on tonearm setup on his website, you'll run across a statement where he flatly recommends raising the back of the tonearm about 6 - 8 mm (from level, or from parallel to the platter), I think it says.

This is actually about right for his vdH cartridges which (most of the time, but not all!) are manufactured with the stylus perpendicular to the top of the cartridge body when the cantilever is deflected under normal VTF.

Following his instructions gives you 1.5 to 2 degrees SRA probably 80% of the time for vdH cartridges (though I still think it's best to check with a scope to make sure.) My point is, that even if you just rely on his recommendation and don't check first, you should still be close enough to the correct SRA to find it by ear without much further up or down adjustment.

Greg's assertion that all manufacturers mount their styli so they have proper SRA when the cartridge is parallel to the platter would be really nice if true, but unfortunately the variations are pretty wide. Even among the products of a single manufacturer. My guess its that it's a difficult parameter to control tightly in real-life production. Also there are three ways I know of for attaching the diamond to the cantilever, so most makers are probably thrilled just to get that pesky diamond stuck to that little boron rod!!

The one thing I've never seen (at least in my economically limited cartridge auditioning experience) is a cartridge which requires the tonearm post be lowered from level (as in "ass dragger") to achieve correct SRA. Anyone who thinks their setup sounds best this way really needs to do the investigation I described at the beginning of this thread. I'm not saying it couldn't happen (never say never) but if I were a tonearm designer, I'd be upset to see my tonearm used this way because it creates a less stable mechanical assembly (relative to gravity) as the vertical pivot center gets closer and closer to, or even lower than!, the stylus' position in the groove.

Gregadd,

SRA actually IS the position of the stylus in the groove. That's what Stylus Rake Angle means. I think we're both saying the same thing, just in different terms.

Dan,

You're right, our arm is low at the pivot. But that makes the cartridge level, at least on this rig. IME ZYX's like to be level.

I'd hadn't thought about it, but I suppose fiddling with the arm during play on a suspended table could be more exciting than you'd like. It's a non-issue on tables like these, as you saw. I can jump up and down and it won't skip, despite the suspended wood floor.

Paul developed his acute sensitivity to SRA soon after we got our first Teres/OL Silver/Shelter rig. On familiar records he can reliably tell me, "too high" or "too low" from the den, two rooms away. It's a bit nuts, but with exposure and an improving system I find my acuity increasing too. Once you start down that path...

BTW, Paul thinks all rock listeners are headbangers! He apparently grew up hoping the British invasion meant those hooligans were all leaving his native country for good. ;-) If I want the house to myself all I have to do is spin one of my (three) rock LP's. Of course for their own safety I do have to hide them.

Seriously, those shrugs were just us acknowledging that it's harder to hear arm height changes with rock than classical. Amplified instruments often become slightly bloated. Many tube guitar amps are tuned for a bit of roundness of course. That bloat masks the nano-timing cues of small SRA changes. Acoustic instruments with quick rise and decay times respond more audibly. Obviously that is both a blessing and a curse.

Thanks again for coming down. It was great getting together with you guys.

Doug's post reminded me that this word "level" is getting tossed around quite a lot. Just so it gets mentioned, the first thing to "level" is the platter. And if you have a suspended table, that means with a clamp and record in place on the platter. (Keep the tonearm in its rest, it won't make any significant difference to "level" in its rest as opposed to sitting on the middle track of the record!)

After that, the position of the tonearm relative to the platter (either parallel or nose-down) will be determined by setting it to provide the proper SRA for the stylus.