Stylus Rake Angle

My problem is that I cannot reliably move my Dino microscope to where I need to in order to take a photo. ... Despite hours of trying to adjust I cannot get a clear or properly positioned shot.

Actually, your problem is that you (and the OP, and Fremer, and others) are wasting hours on a pointless exercise when you could be listening to music.

The number of angels that can dance on the point of a stylus is of greater musical significance than figuring out how to precisely dial in 92 degrees (or any other number) of SRA. That is an utter waste of time and resources. As others have pointed out, 92 degrees may or may not be correct for any particular record. Even if you achieve it you'll have to fine tune by ear, since the cutting stylus may or may not have been set at 92 degrees. There was never any standard for SRA. 92 degrees is just somebody's ballpark average guess, so futzing endlessly to achieve it is nonsensical.

Further, even if you did achieve 92 degrees for one record *and* it turned out to be perfect for that record, it will certainly be incorrect for every other record. You'll have to fine tune again, so why did you waste so much time dialling in that arbitrary number?

Set your cartridge body or tonearm parallel by eye. This should take about 15 seconds. Adjust from there while listening, but only to the extent your ears tell you is necessary. This should take the rest of your life and will be far more satisfying. You may even get to dance with some of those angels, which would be heaven compared to the hell you're putting yourselves through to no earthly purpose.

Harry and Peter got it right.

Thanks, Jazdoc.

Ever since Jon Risch posted his seminal SRA article on Vinyl Asylum, people have over-interpreted 92 degrees +/- 2 as "SRA must be 92 degrees exactly and perfectly". People with a fondness for measurements and exactitude are vulnerable to this distraction. I should know, I used to do it myself. ;-)

Some cartridges do indeed have difficult-to-see styli. My highly myopic eyeballs can spot some contact edges with almost no magnification (e.g., ZYX). OTOH, I once wasted 45 mins trying to spot the contact edges on an Ortofon A90... to no avail. Then I came to my senses, roughly levelled the arm and adjusted by listening. In two minutes I had SRA nailed. From there, readjusting for different LPs (also by listening) took less than a minute. This was an unfamiliar cartridge on an unfamiliar tonearm (Kuzma Air Line) in someone else's system. In my own system I could have done it even quicker.

Good tip about keeping a setup log. That satisfies the need for perfection while actually being useful, lol.

Additionally, once I find the optimal arm height for any particular LP, I note it on a sticky note stuck to the inner sleeve. Makes tweaking for replays quick and easy.

Karl_desch,

It's hard to imagine anyone designing a cartridge for something other than headshell-parallel-to-LP-surface. Why would they do that? It would restrict sales of their own product. Every tonearm on earth, even the wacky RS-A1, is designed to place the cartridge mounting surface parallel to the record.

This doesn't change with stylus profile. I have cartridges with all sorts of styli: conical, elliptical, micro-ridge. All sound best with the tonearm (fairly close to) level. A touch of tail up or tail down? Perhaps. But nothing extreme.

This makes Fremer's reported advice (in the OP) to jack the back of a tonearm up very high quite suspect. He either didn't say that or he wasn't thinking clearly when he did.

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Peter,

Your recollection of what I hear when tweaking SRA was accurate. The most concise description I've heard was Frank Schroeder's, "Adjust for proper timing between fundamental and harmonics." He said that and moved on to another subject, as if he'd described everything we needed to know. And so he had.

If someone doesn't know what that sounds like, they need to get away from amplified music and listen to acoustic instruments in natural environments. It's easy to hear mis-timed harmonics in a mandolin or harpsichord pluck. Electic guitars are more congested. Tracker-action organs like the one E. Power Biggs built in Cambridge are easy, at least when played staccato. A Sears Silvertone? Not so much.

Of course the more resolving the cartridge and system, the easier this is to hear. Lower resolution setups may not reproduce enough audible harmonic information. If they do, they may smear things enough so that timing shifts actually do sound like a change in frequency balance. This may account for different descriptions of what people hear when adjusting arm height.

Csontos and Peterayers hear exactly what I hear.

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Lewm, sorry we haven't explained this in a way that helps you understand this as a timing issue. Thanks for hanging in there.

Of course you're right that the spinning platter controls the timing of the MUSIC. If a TT runs slow or fast, the pace and pitch of the music will be off. If TT speed varies, we hear pitch shifts.

With SRA we're talking about a timing on a much smaller scale: the *relative* timing of the component parts of a SINGLE NOTE. This kind of timing has nothing to do with pitch or rhythm. TT speed does not affect it, SRA changes alter the internal timing of each note even when TT speed is perfect. In fact, they're easier to hear on a TT that maintains highly accurate speed.

Peter wrote,

If the fundamental is being obscured by the harmonics, the harmonics are arriving too early. I hear this when the arm is too low in the back. If the fundamental occurs unnaturally early, or there appears to be a minute lag before you hear the harmonics after the fundamental, then the arm is too high

I think he got the arm positions reversed, but the effects he described are exactly what I hear.

As for a mechanism to explain this, I can only offer conjecture.

Fact: the cutting stylus had *some* specific SRA. This results in a unique cross-section for each and every complex set of groove modulations that make up what we call a "sound".

Assumption: to trace each cross-section exactly, the playback stylus must have the same SRA.

If the arm is too high at the pivot, the tip of the stylus will encounter each modulation before the the top of the stylus does, ie, too early. If the arm is too low at the pivot, the tip of the stylus will be slightly behind the top of the stylus, ie, too late. In either case, the stylus will "slur" across the modulation instead of encountering each part of it simultaneously.

If the playback stylus "slurs" across each modulation rather than tracing it *exactly* as cut, the aural effect is that harmonics arrive either too early or too late RELATIVE TO their fundamental.

I would not argue that this is necessarily what is occuring, but this is what it sounds like.

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Raul mentioned dynamics. Optimal SRA provides optimal micro-dynamics. If the playback styles traces each modulation as cleanly as possible, cantilever excursions will match the path of the cutting head as closely as possible. To the extend the playback stylus "slurs" across modulations, cantilever excursions will be reduced and slurred in time, reducing dynamics.

I find this harder to hear than timing errors in fundamental vs. harmonics, but Paul finds it easier. With regard to SRA changes, I believe he and Raul hear similar things.