Turntable upgrade recommendations: SME vs AMG vs Technics vs other

@lewm 

"Could be you are saying that to couple a low torque motor with a heavy platter is a good thing, because speed in such a design is primarily maintained by the rotational inertia of the heavy platter. "

YES. In my rig, the platter must be accelerated by hand, as the motor is scarcely strong enough to maintain speed. This is the 'quirkiness' that I referred to in my first post - if you don't mind a bit or quirkiness, you can improve sound and save money at the same time. The late lamented Tom Fletcher used this principle to great effect. I have one of his better efforts too, but the air bearing puts it to shame.

The belt drive analog of that philosophy is also coupling a very weak motor to a very heavy platter, first done by both Walker Audio and Nottingham Analog.  There is a stock argument against that approach, but I don't pretend to know whether it holds water or whether the weak motor/heavy platter is wonderful. Enjoy it if you got it.

I agree with Raul. The argument about active devices and noise makes no sense to me.  Any phono stage must develop lots of gain in order to amplify the very low amplitude voltage signal from a cartridge.  This can ONLY be done with active devices, or did you plan to build a phono stage with passive components only?  The trick is to minimize the noise while realizing the gain.  Different designs do it differently and with more or less success.

@lewm 

"The trick is to minimize the noise while realizing the gain."

Completely agree. Obviously active devices are essential. My phono/pre uses three stages of them.

My point was this: "Why introduce a host of active devices to reduce pops and clicks, when we know that pops and clicks are partially caused by instability? There's a good chance that the money is better spent reducing instability in the phono/pre, not least because every active device produces noise."

Perhaps I'm not being clear today. Is so, sorry about that.

@lewm , I am pretty sure as I explained above air bearing tables are different. Air is very compressible. As the weight on the air cushion increases it stiffens increasing the resonance frequency faster than the added mass lowers it. As for the Motus, the low torque motor won't bother it at all. I can imagine a little shake on start up but that would be about it. The suspension is made up of three rather beefy looking leaf springs. Have a look at a picture. Will it effect speed stability at all? A wow and flutter spec is not mentioned. It is servo controlled but exactly how is not mentioned. The frequency of the suspension is 2-3 Hz. 

If you haven't noticed already I am a silly guy. But, if you like Lencos go out and get yourself one:)

@drbond , I think Raul may be right on that. The Verisimo is more compliant and tracks better. It is using the same diamond cantilever as the Anna Diamond and I am drawn to the naked cartridge body design.

@terry9 , the question is is an air bearing turntable worth the complexity over a spindle and opposing magnets. Is the bearing going to be noticeably quieter. If you factor in the compressor that answer is definitely not but, just thinking about the bearings proper the answer is also no. The amount of noise on the record far exceeds what even a mediocre belt drive makes. I admire you for making your own table. That is very cool. I am reduced to making just the plinth. I did think once about making a turntable around a Clearaudio magnetic bearing. That fell by the wayside when Sota announced it's magnetic bearing. If I had the money to by any turntable I would get a Dohmann Helix.

Agreed, the compressor must be in another room. Disagreed about intrinsic noise of the air bearing. Empirically speaking, the higher end Nottingham Analogue (improved to Dais specification and anti-resonance plinth) does not compete with the air bearing, so obviously the statement, "The amount of noise on the record far exceeds what even a mediocre belt drive makes," is false or irrelevant.