Ok, so first let me say that you can ask ten different audiophiles this question and you will likely get ten different versions of why they think one or the other is best. I suppose I’ve developed an equally biased opinion, so I’ll tell you why I’m biased in advance.
Over my my 35+ years in this endeavour, I’ve owned countless turntables. Unfortunately, I’ve never owned an uber high-end belt drive turntable. All the belt drive turntables I owned were middle-of-the-road high-end quality, the likes of Garrard, Marantz, Dual, BIC (anyone who remembers those will also remember just how crappy they were), and… Thorens. I saved Thorens for last since I know that’s gonna ruffle the feathers of some of their fans, but I’m sorry I’ve just never owned one that I considered capable of top-notch audiophile quality music reproduction.
Enter the Techniques SP-10 MkII into my world at age 17 and the peak of my vinyl obsession at the time. I had a summer job at Audionics of Oregon building amplifiers and somehow managed to acquire an SP-10 MkII at the same time I had a set of the TOTL (top of the line) Magnepan Tympani IDs (some consider this the best speaker they’ve ever made, or anyone’s ever made, to this day) and the best amplifiers of the day to drive them.
What a deck the SP-10 MkII was! It was the first time I really heard my vinyl sing. I suppose it was the first truly high-end turntable I owned and it was revalatory. I combined it with a Decca tonearm and started with a Decca phono cartridge, later entering the world of LOMC (low output moving coil) cartridges with the Denon 103 and a pre-preamplifier I built myself.
It’s like so many things in life, there’s only one “first time”. So I’m not gonna dis belt drive turntables here. I’m sure there are many fine examples, I’ve just never had the pleasure to hear one. What I have experienced from the belt drive turntables I’ve owned is unstable speed control (most of them run off a syncrounous motor, which means the speed of the platter is determined by the AC frequency of the power outlet on your wall), amazingly unstable sprung platforms that visibly bounce around, especially with records that are punched off center (not uncommon, at all), and noticeable wow and flutter due to the nature of the drive mechanisim.
So higher end belt drive turntables have external speed boxes and implement elaborate acoustic isolation schemes other than a set of four cheap metal springs. But, we’re talking about some serious cash to get into that game, easily $10K+ these days. Even back in the 1970s, belt drive turntables that really took advantage of the format were several orders of magnitude more expensive than their direct drive equivalents. I picked up a used SP-10 MkII for a few hundred bucks and couldn’t have been happier, dodging a multi-thousand dollar bullet to get into the “best of the best” turntable realm.
Ironically, after 30+ years, direct drive turntables are making a come-back and vendors such as VPI are now calling them the new “reference” and the new price is $30k+. It seems like everything I loved about high-end audio in the 1970s is coming back, but with a price tag over 10 times the original, even correcting for inflation. So do they think we forgot how they sang the praises of belt drive turntables for so many years and are now offering direct drive turntables at exorbitant prices as something new?
While I understand the theoretical draw backs of direct drive turntables, such as potential motor noise reaching the stylus, I’ve never heard them. Whereas I can hear a mid-fi belt drive turntable mishandling vinyl across a room. That’s why when it came time to get back in the game I choose a direct drive Denon turntable from the late 1970s, and not even their TOTL model (since most of those were automatic). I’ve had to work with it’s grossly inadequate acoustic isolation scheme (no mass loading) but after a great deal of tweaking and DIY (do it yourself) trail-and-error, I’d be hard pressed to find a better sounding deck for my Maui system at any price, be it direct drive or belt drive. Check out my review and comments at Denon DP-790W turntable review.