What's the deal with idler turntables and do they have a place in modern HiFi?


After going through a complete overhaul of an AR XA I've been tempted to take a step further back in history and restore an old Rek-O-Kut idler turntable. Can't remember the particular model number from Craigslist, but it seems like it may be an interesting project and far more customizable than the XA, especially when it come to the tonearm. The one I'm looking at comes with the original tonearm, but my guess is that it's even more garbage than the stock XA 'arm and I'd certainly replace it!

However, I don't generally become invested in something if it doesn't pay off. So if the sound is going to be dreadful because it's an idler, then I'll steer clear. But if the sound is bitchin' then I'll jump on the opportunity!
128x128mjperry96
The "problem" with this hobby is that there are frequent instances where we have phenomenon A associated with physical fact B, and the natural human response to such coincidences is to ascribe A to B.  But we almost never have good scientific experiments to prove or debunk such associations.  Thus we are all floating in a sea of subjective judgements, and there is an industry based on tweaks that thrives upon our ignorance. (Sorry, but I do not think the Timeline is much better than a well designed strobe, like the KAB, for looking at instantaneous deviations from correct platter speed. However, if you DO see a speed deviation with the Timeline, you do have a problem.)

The "problem" with this hobby is that there are frequent instances where we have phenomenon A associated with physical fact B, and the natural human response to such coincidences is to ascribe A to B. But we almost never have good scientific experiments to prove or debunk such associations. Thus we are all floating in a sea of subjective judgements, and there is an industry based on tweaks that thrives upon our ignorance.
Very well said, Lew, IMO. I would add that in audio there are countless variables that can be cited for which it is not readily possible to define a quantitative threshold separating what may potentially be audible in some systems from what is unquestionably insignificant. In the absence of that kind of quantitative perspective there is essentially no limit to what a perceived or claimed sonic effect can be attributed to.

Best regards,
-- Al
Spot on - Lew & Al. 

One false link I alluded to above (my first rim drive experiment) relates to incorrectly ascribing massive torque as the reason for rim drive's attributes.  Actually, it's the architecture itself (rim drive) that is responsible for this. 

This isn't an argument for or against high torque, but rather (as you both stated) to not jump the gun in terms ascribing causality.  This of course goes further down the rabbit hole - that we may well have the equipment, but not know what we really want to measure.

Indeed, a Timeline is no better or worse than a KAB, and at the speed level of granularity responsible for intermodulation distortion, the Feickert is also useless.  At this point, all I can use these tools for is to observe a (likely) loose correlation with what I and my listening panels are hearing.

Cheers,
Thom @ Galibier Design
There is also a price to pay when the platter is massive. Light weight platters have been preferred by any "well-designed" TT designers for the same reason.

I am yet to hear any belt drive turntable sound like a direct or Idler drive in resolving the pitch and rhythm of music. For some it is not very important.