Hi Robin
Well, there are a few more, some quite lengthy, I don’t know if you have the time and patience to go through them (from the more recent to the older)
Moving-Magnet Head Amp - without RIAA
Cartridge dynamic behaviour
Measuring phono stage RIAA accuracy with a computer
Turntable speed stabilty
mechanical resonance in MMs
Digitizing vinyl
vinyl coefficient of friction
George
If you want me to repeat my measurements on the pink noise tracks from the CBS Labs (saying RCA was a simple mistake on my part) disks I could, you simply play them at another speed to see that the resonances are on the disk not in the tonearm and cantilever. Spin the disk slow enough you can hear them. I also don't see why you lump MM with MI cartridges the inductances are typically an order of magnitude apart. My Grado is is not very sensitive to cap loading at all.
I am way behind guys like GrooveT and JP in terms of vinyl setups but we respect each other and try to share some knowledge that might help others. Some of what we have done is well beyond the obvious.
I repeat here a constant velocity sweep from JP's setup, IMO a constant velocity sweep with no RIAA is the best test because it directly pits the ideal transducer responses against each other.
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A few more with rich technical content (and the pleasure to share)
Cross-talk measurements vs frequency?
Aurak, technical reference as addendum to Cart. Dyn. Behav.
Designing a universal diff-in/diff-out Head Amp
A simplified universal differential or single ended phono preamp
MPP
George
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Curious: 1.8s would make sense, adjacent to groove horns raised by a heated cutter. The other possibility is master tape print-through, where a single end-of-tape wrap at 15ips might be shorter. Especially distracting for speech recording, I used low print-through tape stock, and stored the tape tails out because rewinding before playing could significantly reduce the pre-echo.
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Many thanks, George. Some look familiar, so those I've probably already read, and likely picked up a few gems. However I must say that because online conversations tend not to be peer reviewed or in any way edited and vetted, most of my studies have been scientific papers and technical books by experts, plus my own lab work. Audio is a science, so having had professional experience over 59yr, my purpose on this thread is to be helpful and share some of it, even if the information has been previously revealed, signals a change in knowledge, or risks disagreeing with a member's long-held beliefs.
Thanks for putting this summary up but I don't see much use here. Beliefs that must be held at all cost goes both ways.
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Scott, I am not calling out your misstating "RCA" instead of CBS, only to clarify for the record. Your "in-groove recorded resonance" sleuthing is brilliant - the frequency(ies) could very well identify a lathe issue.
I use the CBS STR-140's narrow band pink noise sweep which avoids frequency dependent artifacts in the groove, such as the resonance you found, and reveals a truer cartridge response.
I only "lump" MM\MI that typically required C-loading to differentiate from MC, which does not. The image is for your Stanton 681 and shows the dramatic effects of off-spec C-loading. Pickups with a different inductance still show similar effects, though they are proportionately milder. [Image when I figure out why I can't now.]
Your\JP's constant velocity sweep without RIAA is interesting, but at the moment I'm missing the intention. Note the center of the X-axis is 10kHz, the 2nd harmonic 20kHz, and the 3rd harmonic 30kHz, so from middle to right of the chart distortion is ultrasonic and thus inaudible. Within the audible range, the distortion might appear reasonable - on the order of 1% or less - but would be significantly higher after RIAA HF emphasis. (Is any of this what you mean for me to see?) Of course any non-linearity produces HD and IM, the difference products of which could fall within the audible range. And I'm sure you know that non-linear distortion from groove mistracing is due mostly to the stylus tip shape, and far less the cartridge mechanics.
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If you're implying me, I repress sentimentality for any "beliefs." I change my mind often when presented with credible evidence - the beauty and expectation of the scientific method. It just might take me time to wade through it all.
What methods are people using for fine tuning anti-skating and stylus azimuth? I've recently tried some new (to me) electronic methods. Just wondering what other folk are doing.
An excellent example, play the 1/3 octave noise band centered at 14kHz people our age should hear almost nothing. If you you have a set up that does that I would love to see a .wav file posted.
I was more interested in the low frequency asymptotes on the THD plots. One would think the distortion would keep going down with frequency from stylus geometry arguments, the small signal power law behavior with increasing frequency seems to be a decent fit (similar to 2nd and 3rd order intercept in RF).
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