Artisan Fidelity "Achates Idler Drive" Turntable
- Thread starter lapaix
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Bruce B., Each respective drive type (Belt/Tape, Idler, Rim, Direct) does indeed portray analog playback through a slightly different light. Interesting to note, given their goals are essentially the same although not surprising when one takes into consideration the dissimilar methods of employed mechanical engineering.
I am going to ask Christopher a dumb question but for the sake of many of us out here can you describe how an idler drive works and what are its virtues
Ever own a Dual 1009? 
The problem back then was that the rubber ring that drove the platter often wore unevenly leading to speed fluctuations
The problem back then was that the rubber ring that drove the platter often wore unevenly leading to speed fluctuations
Simply stated, an idler drive transmits the rotation of the main shaft of a motor to another rotating device (ie. a wheel) which in turn directly turns or "drives" the platter. Throughout history there have been many examples of such drive types, some more evolved than others. Examples: EMT 927, Garrard 301, Lenco L75, Thorens TD124 (and many more). Notable characteristic traits are superb dynamics, bass drive/impact and accurate portrayal of scale. Execution and implementation is key, as without a competent and well conceived foundation any design no matter the drive type will inevitably fall short. Turntables, whether employing direct drives, belt/tape drives or idler drive based designs all can be brilliant when properly employed.
Now that is a fair and balanced statement. Too often advocates say one way or the highway.
rockitman, agreed and interesting how enthusiasts often can be so divided when this topic is discussed. In my experience, all drive types have their merits but in the end personal choice (read: subjectivity) is time and again the final determining factor.
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Big changes are coming to the Achates! Chris now has an inverted bearing that will be put into the Achates. It has taken this table to whole new level from what i understand. I am hoping to get mine within the next month or two, once i do i will report back. Maybe Chris can post some pics of it if he wants i will leave that up to him.
Worldcat, yes, the Achates inverted bearing system which began in early concept form nearly 2 years ago, is now ready for production. Several final revisions are being outlined but a completed sample has been run here in the primary testing system for a couple of weeks and is even outperforming my initial expectations in certain key areas of playback which had not been anticipated even during the design goal phases.
Worldcat, Inverted bearing designs, as Myles A. previously stated, have been around for quite a lengthy period of time in so far as high end audio turntable application is concerned. Certain advantages exist with inverted bearings, namely the lower center of gravity and diminished "wobble" or as some describe as the "topple" affect which is present to a greater extent in a conventional type bearing. As no bearing design is entirely without flaw, including air type/floating magnetic bearing systems, the inverted bearing vs. conventional advantage will be inevitably limited to inherent design integrity and implementation. Or rather, in operation, a well conceived conventional bearing will exceed the performance of a poorly conceived inverted bearing and so forth... A precision turntable bearing should exhibit ultra low friction and vibration/oscillation artifacts as to not propagate these anomalies directly back through the stylus during record playback. The tricky bit is to do this all while trying to maintain as little mechanical "play" as possible between the rotation of the platter, bearing spindle and sleeve while at the same time ensuring the lowest possible friction and utmost levels of stability. A challenge indeed!
With kindest respect to Myles, :b for clarification and for those who may not realize, rim drive and idler drive are both different drive types in the context of turntable design.
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During the final testing phases and post bearing run-in, the inverted bearing & revised Copper alloy platter has exhibited an even lower noise floor with increased focus and resolution over the conventional configuration. Furthermore, I've noticed greater speed stability and less distortion at high spl's, the clarity and playback presence of musicians and artists within a recording have reached a whole other level for the Achates platform.
So, needless to say, more re mastered 45's are on the way!
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I am curious how they differ other than semantics. On my old Dual 1018, the idler was a rubber pulley/wheel driving the platter.
Basically, the only difference as I see it is the size of the "pulley" driving the platter and as in the following video drives the inside of the platter whereas the VPI drives the outside of the platter.
There's the TTWeights rim drive here:
or the modded VPI here:
These drives are often mistaken for one another due to their obvious similarities, as they both couple a spinning "rim" of sorts to accomplish the end goal, it can be confusing at times to discern between them.
The difference lies in the mechanical component coupling, whereas the rim drive couples the motor directly to the platter periphery by means of direct motor to rotating spindle contact, the idler drive couples the rotating motor spindle to a passive rubberized wheel which once engaged provides the rotational force and simultaneous secondary point of contact at the platter side which sends the platter into motion.
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