If we are going to have a serious discussion about the mechanical requirements of a turntable, we need
@Frank Dernie in here.
I've never owned at turntable with any claim to the state of the art. But even the lowly TP-11 tonearm on my TD-166 plays surface noise less loudly than the visibly sloppy tonearm on my Technics SL-20.
Back in the deeps of time, say a little over 30 years ago, I listened to a comparison made using the same speakers and cartridge models between a Rega, a Linn Axis, and a Linn LP-12 of the day (which I seem to recall had the Valhalla power supply, though I doubt that makes any real difference). There was a difference in the way the turntables were made, to be sure. I don't recall much about the Rega, except that the price given to it at the time was around $500 (the Axis was somewhat more; the Sondek something around $2500 as I recall). The Axis is an unsuspended table, maybe with some damping mounts (I don't remember), using the Basik tonearm--not a tonearm that gets a lot of respect outside of LinnWorld. The difference between the three, played into the same speakers (Magneplanars) and using the same model cartridges was noticeable. We were listening to Dmitri Sgouros, as a child prodigy, playing Rachmaninoff as I recall. The difference at the time was that loud attacks tended to persist with the cheaper tables, and it sounded to me like the system was adding reverberation. The LP-12 did so noticeably less. Was that how it was placed in the room to minimize acoustic feedback? Was it something superior about the suspension? Was it a different in tonearms? (Not unlikely.) Was it the secret insertion of a capacitor by an unscrupulous sales guy? No clue. (Doubtful on the last one--he had already demonstrated a willingness to keep me from spending money unnecessarily). But my engineering brain thinks it's plausible that vibration and rattling in an acoustic system will have audible consequences, and eliminating those would prevent sharp transients from smearing mechanically in the system. To me, that's a mechanism by which surface noise might be reduced in its audible impact.
I've looked at waveforms of clicks and pops often in order to remove them after making a needledrop, and I have to say I've never seen evidence that the transient was persisting or ringing in the time domain with my current setup. The tail of the waveform is as sharp as the head. I have not compared same between my two tables, but that would perhaps be interesting. It would be difficult, however, to compare using the same cartridge, which would be a confounding element.
My turntable uses an AC synchronous motor with 16 (or is it 24?) poles. The sine wave coming out of the wall at my house is not super well-formed, if I'm to believe my oscilloscope. The sine wave coming out of the Music Hall Cruise Control power supply I'm using (for fine speed control), however, is quite clean and well-formed. Music Hall claims better than 1% distortion and I believe them. Does that have an audible effect? Not in the least. But I do like being able to fine-tune the speed of recordings so I can play along.
I will say that I exercised due care in mounting the cartridge, but even with that had a 1-dB channel imbalance that changing the anti-skate amount to something different from Thorens's recommendation resolved. I have also carefully checked the center bearing and adjusted the suspension. And though it was gross overkill, I was pleased to have an excuse to level it with an SPI precision machinist's level. I also checked the runout on the bearing and relubricated it. None of that made any difference I could hear, except for the channel imbalance, and that mostly had the effect of moving the phantom center a bit to the mid-point between the speakers.
For lots of my old records, I get low-frequency noise in "silent" grooves as high as -40 or -35 dB in the bottom octave, and
the fact that the needle is running in a groove is plainly audible even when there is supposed to be no signal. That has been true for every demonstration of turntables I've ever heard no matter what the price point--every single one. Rarely does it intrude on the music unless the LP is particularly bad--if it's cranked up enough for that background noise to be obvious in my residential environment, music at close to full scale will cause damage.
(Fremer did an online YouTube comparing an LP to a digital source, using some fancy binaural microphone setup he claimed revealed the differences. To me, I heard a bit more of that reverberation in the low frequencies plus it was plainly obvious when the needle dropped into the groove, even after the landing impact. Maybe he thinks that reverberation is an improvement.)
It is also true that digital needledrops are identical in sound to listening to the LP directly--this has been observed many times. For me it's true no matter what the digital resolution (meaning: 16/44 sounds the same to me as 24/96). There is no need for blind testing if one cannot hear a difference sighted--blind testing is a method to demonstrate that a perceived difference is real. There are those who would say that my system is insufficiently revealing, but I rather think that's BS. Others will say my ears are insufficiently revealing, and they might have a point. What it tells me is that if I want to copy an LP exactly, digital is good enough, even when it is capped at 22 KHz and 96 dB S/N. (And that's theoretical--the real world won't be as good.) There's no question of going the other way, of course. I think we all realize that.
Would a much more finely made turntable make an audible difference? I have heard such improvements in my life and the memory of that experience is unfaded. But the difference was subtle enough. I rather think my Thorens, as adjusted by me, is somewhere between that Linn Axis and the Linn Sondek, but of course that is a comparison I have not made.
None of that matters a whit when I'm playing a favorite record. And whatever high frequencies the stylus has peeled off the LP I can't hear anyway.
Rick "who does measure good system response at 15 KHz, despite not being able to hear it" Denney