New Turntable Advice

@cundare2

In Mikey’s extensive Stereophile piece (or was it Analog Planet), he was amazed by the speed accuracy, which George states has a tolerance of about 3 ppm!

Be careful about measurements.  3 ppm seems to be the digital resolution of the motor control system but a lot of mechanism cuts in after the motor itself.

George's website quotes Wow .04% Flutter .04% which is closer to 400 ppm unless my arithmetic is faulty!

Over 100 times less good than the headline impression, it would seem

It’s a shame @albertporter doesn’t post much here anymore--he had a wealth of good tables, including the Walker in its heyday. Albert told me he got into a Lenco with the various mods and liked it, but that eventually led him to SP-10 mk ii and iii. I know he did a lot of work on the plinth, a support for the bearing and other details that escape me. If it were me, and I wanted a top tier table without issues, I’d probably just buy whatever that top Technics is, have a plinth that can accommodate a couple arms and call it a day. FWIW, my main table is the Kuzma XL with Airline, so I’m not trying to sell you on what I own. 

I will say that I bought the very first series SP-10 in 1973, brand new, and with a go over by the late Bill Thalmann, including the Krebs mod, a plinth that accommodates multiple arms, this table has been in and out of service (it always worked but the on/off switch got funked up at some point and Thalmann took care of it)- figure I’ve owned and enjoyed that table for more than 50 years. 

I think it is very hard to compare turntables, almost impossible, in today’s retail environment with the necessary controls over variables. I suspect a lot is based on ergonomics and appearance. Before I bought the XL, I did have the Kuzma Reference with a Triplanar, and using the same cartridge, switched over to the XL/Airline set up. Big difference. But I had the components in my home, in my system to hear them. 

Not sure what your budget is, but I’m a little wary of used electro- mechanical devices. And set up is key- huge differences between ok and "nailed it." I used Mike Trei when I lived in NY. He made it look easy.

@lewm 

back when I was choosing between Lenco and Garrard, there seemed to be a strong consensus among 301 owners that an external motor controller worked wonders

I suspect the external motor controller concept for the Garrard 301 has died a natural death - like so many audiophile tweaks!  At the very least, I have never seen one offered in the stuff I read these days.

What I have learnt in the last few days is that the eddy current drag from the manual speed control might explain the so-called 'slam' of the table.  Once set, it applies a constant drag, against which additional drag from highly modulated passages is pretty insignificant.  Hence the music does not seem to slow down!

If the background drag was just bearing friction plus stylus friction, highly modulated passages would have a much bigger effect in proportion to the overall drag.

The use of an external motor control seems to require the eddy current mechanism to be disabled, so swings and roundabouts ...

An analogy might be a big V8 idling against the drag of a slush-box automatic. Switching the air-con on or off does not change the idle speed much.  But slip the box into neutral and then toggle the air-con and you can watch the revs change.

(In the good old days, US auto-makers like GM and Ford had Aussie production lines that stuffed big V8s into European-inspired sedans - mine would get up to city speed limits at idle)

I am not promoting the Garrard 301, just trying to understand why it is so highly regarded in some circles.  Now I have a plausible explanation of 'slam'

@richardbrand.

"Once set, it applies a constant drag, against which additional drag from highly modulated passages is pretty insignificant.  Hence the music does not seem to slow down!"

Precisely!. It will be slowing down but much less that if there was no predrag .

You described, much better than I, the efficacy of predrag. Of course the motor must be of good quality such that it doesn't become noisy when loaded thus. This is where torque ripple can be a problem as it is a function of current draw , torque output. 

In the Garrard's case the mechanism which sets the correct speed has the lovely positive side benefit of making the drive stiffer. The result, more startling transients, greater apparent dynamics. some may even call this "slam" My guess is that the technicians designing it knew about this

@lewm

What can affect speed of idler TT is wear on the idler wheel and stuff like that

Uniform wear on the idler wheel should have no effect on the platter speed - the idler just transfers its rim speed from the motor pulley to the platter rim.  This assumes it does not slip, and has no wear flat spots.  In normal use, the idler wheel is retracted until the table is switched on, which also mechanically engages the idler wheel via springs.

Provided the platter is not forcibly restrained while running, the hard rubber tyres on idler wheels should last for decades.

Wear on the motor pulley is more likely, though I think very uncommon in normal use.  Changing motor pulleys and idler wheels is straightforward unless you also want to change the idler wheel bearings!  The lower bearing housing is fixed with rivets made of unobtainium