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!
mjperry96
Theoretically, idler drives have better speed control because belts have a stretch component that varies the platter.  In the old days I had a Rek0kut table with a Grado lab arm and his top of the line cartridge of the day....it was belt drive.
I have a Garrard 301 and it is a great turntable, so my answer is yes.
I know several people with systems well north of $100k that have Thorens 124s and Garrard 301 and 401 tables in them.  When properly reconditioned, these can be terrific sounding--quite punchy and dynamic sounding.  I have no idea whether it is the method of drive, the use of high torque motors or some other characteristic apart from the drive method that gives these tables their particular sound, but, in any event they certain can be great in the right system.
Only theoretically idler drives have better speed control, but practically they're not. The idler wheel grinds out quite quick over the motor spindle and certainly changes the speed. All of the motor vibrations directly transferred onto the platter.  The best speed control have quartz direct drive turntables.
What about an idler drive with quartz control ?
If you like noise from rumble they are OK!

Do you want to live in the past?
Hi Gmjperry96,

Given your propensity to play and learn, I say go for it.  I think you'll learn as much about yourself as you will about idlers vs. belts.

I've been working on a new turntable for about 18 months.  It didn't start out as an idler, but the design constraints presented to this chassis layout led me down that path.

The Eiger is definitely a different flavor from our belt driven Gavias and Stelvios.  I'd expect an equal number of people to line up in favor of belts and idlers.  Different strokes and all that.

To don_c55, people were saying that vinyl is a thing of the past as well.  Belts are unquestionably quieter and you'll get a different presentation from a belt driven architecture.  As much as I've optimized my belt driven turntables (and people say that they're very idler like in their rhythmic presentation), the perception of rhythm with the Eiger is completely different.  People value different attributes, and no one is superior to the other.

Cheers,
Thom @ Galibier Design
Hello Thom,
I appreciate your intelligent and honest response. You are right regarding the different types of turntable drive approaches. Be it idler arm, belt or direct drive, each has its strengths and flaws. I wish you much success with your Eiger turntable.
Charles,
Vintage idler wheel drive turntable (Thorens 124, Garrard 301 and 401, Lenco) enthusiasts (including Art Dudley) cite the design's "forward momentum"/"rythmik drive" sound characteristic, supposedly a result of the high torque nature of idler wheel drive.

bdp24,

As I stated above, I don't know why the idler tables I heard have the kind of "drive" that they do have, but, I suspect it has to do with the high torque motors employed.  I have heard the same sort of sound from the three motor Audio Note table and it is a belt drive table, but, it employs three massive motors, each of which supposedly is a 2 hp motor (three massive power supplies are also used to power the motors).

It would be interesting to hear what a modern idler table sounds like.  I would love to hear the Galibier table.

 

wow 6hp for tunetable??? 
it's larger than my darn lawn mower!
Heh, I better concentrate on lawn moving again, it´s relaxing and expands mind

I invested in a Jean Nantais Lenco, Idler drive, $10k.

In comparison: CD's are unlistenable, SACD and Hi-res aren't bad, DSD downloads are better, vinyl eclipse all of the above, and not by a little bit.

Your miles will not vary. But, stay away from re-issues.

I own a Artisan Fidelity Lenco Idler drive and it put to shame my modern belt drive table.  Go listen to a well restored idler drive table and make your own decision.

Since you obviously enjoy restoring vintage equipment I expect you will enjoy the idler restoration project as well. These tables are in high demand and prices for a Rek-O-Kut or Garrard 301 will very likely not come down - so your project should be a good investment. Once you experienced the sound characteristics of a good idler drive you will not want to give them up again. And you will be able to listen for these qualities in other designs. Either way, you can only win. I did the same with a Garrard 301 and learned a lot about the importance of the drive system in regards to sound. Even though I ended up replacing the Garrard, I knew what sound characteristics I was looking for. But you may very well stay with your Rek-O-Kut, if the weaknesses of the idler drive system don’t bother you. I’d say go for it!

www.lencoheaven.net/forum

http://www.high-endaudio.com/RC-Tables.html




don_c55,

I have a Dual 1229, a Garrard 301, and am restoring a EMT 927.  None of these has any audible rumble or noise.  After having several nice belt drive tables (Linn LP12, Ariston rd11, Thorens TD165, and Thorens td 125), none of those could hold the pace, pitch or power of my idler driven tables. The Dual is so quite and the background so black it's incredible. I use a Grace 747 with that table and it's wonderful. The Garrard is a freaking legend and it too is incredible. No table that I know will best the EMT 927, at least not to me.

mjperry, I wouldn't recommend a Rec O Kut as a first venture into idler drive. Try a Thorens td 124, or a Dual 1229, or a Garrard 301, or a 401.  If you try a Dual, I recommend replacing their very nice but not so flexible tonearm with a Grace or a SME.

Experiencing a well tuned idler drive table is quite addicting. Unless you're going to venture into five figure turntables, they are really hard to beat.

Norman
Thanks for the kind words, Charles.

We all continue to learn, and the untapped "goodness" in idlers certainly caught me by surprise. That Dagogo review is beginning to look dated, although I stand by my comments that rigid belt coupling gets you a large part of the rim drive sound.  Direct and idler/rim drive are definitely not for everyone (what architecture or product is?), as they have a different set of virtues and drawbacks.

larryi:

bdp24, 

As I stated above, I don't know why the idler tables I heard have the kind of "drive" that they do have, but, I suspect it has to do with the high torque motors employed.  I have heard the same sort of sound from the three motor Audio Note table and it is a belt drive table, but, it employs three massive motors, each of which supposedly is a 2 hp motor (three massive power supplies are also used to power the motors).

It would be interesting to hear what a modern idler table sounds like. I would love to hear the Galibier table.

Since my experiments began with identical drive systems (motor,  controller, bearing and 33 Lb. Gavia platter), I can safely say that it's not about massive torque (relatively high, but not massive). 

The first thing that jumped out at me was the difference in time that it takes for the platter to lock speed (observed with both Feickert software as well as a Sutherland Timeline).  The idler locked in much more quickly.

It's pretty clear that we're hearing control of the braking motion - what would be the "back" or "slack" end of the belt that the idler idler is grabbing control of, but which a belt isn't capable of doing.  If you buy into the concept that both acceleration and braking need to be controlled (or alternatively, that a drive system needs to be immune to both of these forces), then none of this should come as a surprise.

Given how we've learned that a stylus tracking at 2 gm. can modulate the speed of even a massive platter, we shouldn't be surprised that some speed control benefits could be gained.  

Of course, the questions remain as to how audible this is, how it's perceived, and how musically significant it is.  From initial auditions of late stage Eiger prototypes, people are noticing the differences in presentation, and are definitely split in their preferences.

I'm really excited to return to the Eiger, and as soon as I get my head out of the NiWatt amplifier design (Labor Day?), I'm looking forward to returning my focus to the Eiger.  There's a lot of untapped potential, and it's been patiently awaiting my attention. 

Cheers,
Thom @ Galibier Design



thom_mackris

Given how we've learned that a stylus tracking at 2 gm. can modulate the speed of even a massive platter ...
I've seen this claim before, but never seen any proof of it. I've measured the speed of my turntable with it 22-pound platter as it plays an LP and never detected this sort of speed deviation.
I believe it is safe to say that maintaining absolute platter speed in the presence of an ever changing load (friction from needle tip) is physically impossible! One can try to minimize speed fluctuations - but will never eliminate them completely! 
Regulating designs need to measure a speed change first in order to correct the speed. 
Unregulated TTs like the Garrard try to minimize speed changes by employing high torque motors. The speed-torque curve of the motor needs to be as steep as possible to minimize speed fluctuations from a changing load. 
The over all flexibility of the drive system is another important factor. That's where idler drives have their strong side! 
The flexibility of any drive system can be measured by applying a defined torque to the platter while locking in the shaft of the driving motor. The resulting angular movement of the platter allows to determine the flexibility of the drive system. Belt drives with very long and flexible belts allow more platter movement - idler drive systems with direct coupled idler connection and stiff motor support allow very little angular platter movement with same amount of torque applied to the platter. 
These thoughts lead to the conclusion, that a high torque motor with steep speed torque curve plus a drive system with little flexibility between driving motor and driven platter is a must - no matter if speed regulated or not. Not all modern TTs follow these principles - but some do. And I believe that some modern designs are able to achieve these goals even without employing an idler drive arrangement. A short and rigid belt driving a small sub platter follows the idea of little flexibility in the drive system. In combination with a high torque motor the result will minimize speed changes from the ever fluctuating load caused by the needle tip ... 
Hi Cleeds,

I’ve seen this claim before, but never seen any proof of it. I’ve measured the speed of my turntable with it 22-pound platter as it plays an LP and never detected this sort of speed deviation.

I stand (partially) corrected ... primarily because I didn’t want to blow my own horn. I’ve seen stylus tracing induce speed instability on some turntables but not on Galibiers. Mass absolutely helps.

Cheers,
Thom @ Galibier Design
decibell
I believe it is safe to say that maintaining absolute platter speed in the presence of an ever changing load (friction from needle tip) is physically impossible!
Please explain how the speed of a 22-pound spinning platter can be altered by a stylus whose force is measured in grams.

Please tell us about the measurements you've made that support your belief.

Belt drives with very long and flexible belts allow more platter movement - idler drive systems with direct coupled idler connection and stiff motor support allow very little angular platter movement with same amount of torque applied to the platter.
There's no "angular platter movement" on my belt drive table. It's a VPI.
thom_mackris
... I’ve seen stylus tracing induce speed instability on some turntables but not on Galibiers. Mass absolutely helps.
Agreed! If the movement of a phono cartridge stylus affects the speed of a turntable, there is something very wrong in the turntable's design.

Stylus drag is surprisingly strong, platter´s very high mass helps but does not eliminate it. 
harold-not-the-barrel
Stylus drag is surprisingly strong, platter´s very high mass helps but does not eliminate it.

I'm with Thom. There's absolutely no measurable or audible slowing of a turntable platter caused by "stylus drag" if the platter is of sufficient mass and the rest of the turntable is properly designed.

Of course, if you're using one of the common, cheap, lightweight turntables, then I suppose it's possible.




cleeds
There's absolutely no measurable or audible slowing of a turntable platter caused by "stylus drag"

This was talked to death in the Sutherland Timeline thread.
Not measurable was put to rest forever.
totem39573 posts.
Regarding "stylus drag" affecting the speed of  a properly designed turntable with a platter of sufficient mass:
Not measurable was put to rest forever. This was talked to death in the Sutherland Timeline thread
You're clearly mistaken, because there are two people in this very thread who have contrary evidence. One of them is Thom, a turntable designer. As for myself, I've actually made the measurements, rather than just relying on others' opinions.

It's easy to understand if you think about it. So-called "stylus drag" is a deviation that would be measured in fractions of a gram. If you consider a 22-pound platter spinning on a low friction bearing, it's pretty far-fetched that such a tiny change in force could have such a big effect.

I've even tested this with the Telarc 1812 LP, which has some of the most heavily modulated grooves ever pressed on LP. Note that this is also on a turntable that uses a threaded reflex clamp; that eliminates the chance of the disc itself slipping on the mat, which of course would skew the result.

To be clear, I don't doubt that this is a problem with some LPs on some turntables. And LP playback is surely fraught with challenges. But the effect of stylus drag on platter speed? That's a solvable problem.

I will say this, as far as measurements are concerned. At present, my best tools are the Feickert Pro software and a Timeline, and I’m not seeing any effect (can’t directly measure music with the Feickert, unfortunately). I’ll leave it open to the possibility that at a finer level of resolution, there may be a drag effect, but somehow, I doubt it.

Remember that speed changes occur in varying time domains. At the finest level of granularity, we hear it as distortion. If you’ve never read the IAR review of the Rockport Sirius, the first page of this lengthy tome is a good read for an analog-file. Worst-case, it will cure your insomnia ;-)

http://www.iar-80.com/page12.html

Cheers,
Thom @ Galibier Design
Here´s Teres Audio´s article about http://www.teresaudio.com/manuals/teres_speed_tech.pdf
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.
Pani, I think your generalization about light weight vs heavy weight platters is very much open to debate.  One could just debate your point that light weight platters are a given in a "well designed" product, but is it really worth the trouble?  Seems to me that there are many great turntables, especially of the belt-drive variety, that take advantage of massive platters.  But yes, I agree, there's a price to pay, just as there is a price to pay to optimize any design choice.  I also share your predilection for idler- and direct-drive vs belt-drive, but because I have held on to that bias for 4-5 years now, I feel I need to keep an open mind; I've lost touch with the belt-drive sound and no longer feel qualified to reject it out of hand.  

Dear Lew, Even this quasi scientific approach is to prefer above

the Almighty as cause and reason for everything. However I do enjoy

those mythical properties of new products till I have read comments

in our forum.

Dear All.
I suspect that the heavy/light platter debate will always have its disparate points of view.
 What we are  really talking about is low or high inertia platters and the matching of these to drives of sufficient torque, intimately coupled to the platter, to tightly control their speed. (Putting aside, for now, the high inertia, low torque design espoused by some. A completely different design path)
I agree that we don't have the tools, other than our ears, to measure the efficacy of these two design choices, but in my experience a high torque, high inertia drive trumps its opposite. 

You are no fun Richard!!!  You stated the facts we can not measure it so now what are we going to debate about.  The ones who want to bring in numbers all the time are the ones who gave us CD's, transistor amps and of course tilted up mc carts.
We don't need no stinken tone/body/drive and emotion in our music.

Just having some fun here!!!  For the record , At this point in time, high mass high torque best so far.  Don't get me started on wooden tonearms.

Enjoy the ride
Tom
Hey Tom.

Who would have thought that music is about emotion, how it makes us feel!

As you say, some get tied up in he numbers, but the acid test is 'How does it make me feel?"

No emotion, no contest.

cheers. 
Hi Pani,

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 would state this differently:  no single parameter can be optimized without taking the entire whole into consideration. Any architecture will always have strengths and weaknesses. Intelligently optimized, varying architectures converge but ultimately still carry their basic DNA (the architecture's key attributes - their strengths and weaknesses).

Cheers,
Thom @ Galibier Design
Thom and Lewm, when I brought out the high mass vs low mass platter thing, the idea was not say one was superior over the other. Rather I wanted to point out that while high mass is a "workaround" for the torque generation in belt drive systems ultimately it has its own downsides too. At its best it is just a "workaround" with strings attached (no pun intended). Torque should come where it is supposed to come from and thats from the motor.

I am not a TT designer but having heard many turntables (most of them are belt driven and many of them with heavy platters), less than 5% of them actually could hide their "high mass" artefacts. So, for me it is just statistics
Thom
Have you considered introducing a little series R Into the power supply and scoping the motor current draw to vicariously look at stylus drag as a function of motor current draw?

cheers 


"Torque should come where it is supposed to come from and thats from the motor. "

imo - the torque should come from the part the record interfaces with - the platter. 8^0

@mjperry (OP) I own a direct drive, idler drive, and previously a number of belt converted to thread drives.  My reference is a string drive.

You can see the idler drive I own on my virtual system. I think they are alot of fun (especially with rock music) and remind me of big American iron cars from the 70's.

Great in a straight line, but noisy. and hit that first curve and you realize the part that is weak ... the brakes.

From an audiophile perspective most noticeable on Classical music with big dynamic swings meaning big groove modulations followed by small. The wheel can't slow down, and gives you a little blip in the sound - an upbeat so to speak - that I personally feel imo that some like to call PRAT :^)
   
The above is a memory taken from a serious audiophile nervosa phase.

Again really fun tables, but you can't just buy a stock table and build a plinth for it. There will be a big learning curve.   

The best designs I have seen - imo - focus very heavily on decoupling the plinth from the noisy motor. Mine is multiple layers of different wood and has large voids in the 100 lb plinth where the armboards bolt to.
Hi Ct0517

Do you have a favorite string you use?  I has been playing with 10-14 guage silk.

Thanks Tom
Here's my two cents worth....I've had Rek-o-kut turntables that I have rebuilt that sounded so bad that you would give up records if you had to listen to them ......Save your money, buy a Rega....I would say buy a VPI but you can't get parts for them.......I also had Thorens, which play good some days and other days not so good.....Those old turntables are like time bombs, there always something breaking or slipping or smelling bad......BUY NEW......autospec
Okay, here's another version of the question...

I have a VPI TNT IV, which came with a single idler flywheel, (not the extra three you sometimes see around the edge; apparently, there are quite a few versions of TNT). The base has three holes for the weird three-point idler mechanism but mine doesn't have it. The motor drives the idler flywheel, which is very heavy and has a larger diameter pulley than the motor, then another belt from the flywheel idler drives the platter round and round. I'm sure the idler flywheel is designed to both separate the motor from the platter, and with its weight, damp any transferred motor vibration and speed variation.

Since VPI got rid of the idler flywheel for later models, I've been toying around and did that, too..

So what happened? Did the world fall apart?

Honestly, I can't tell the difference. And without the idler flywheel, the whole turntable "package" makes a much smaller footprint. With and without the idler flywheel, I've been using the odd but yes-it-works-great piece of dental floss to drive the turntable platter. And the VPI SDS speed controller in both cases (the only way to get 45 RPM), so the only A/B difference is eliminating the flywheel idler.

The base it sits on is very heavy and damped, and it's using the stock VPI spring-loaded isolation/leveling feet which supposedly aren't the cat's meow but seem to work fine for me. The stock 12.5 tonearm with a Shelter 90X cart.

Anyone's thoughts? Has anyone else tried just simplifying the drive that way? It certainly looks more steampunk with the extra belt and idler gizmo, but simplicity is appealing. What intrigues me is this is essentially what VPI did in later models.
I have a lenco on a massive aluminium plinth and no more noise than a belt drive. I had a pink triangle pt too before.
Hi Tom
I went through many threads years ago with the vpi table. With the verdier i do have his French thread but prefer one i found at fabricland. Gutermann but the exact one i need to look further.. the deck has  been designed for thread so its string/thread is applied very loose. This technique would never work on a belt drive being converted to thread.

In a bit of a crisis as i up at the lake and my lenovo, not to be confused with lenco, just died on me. Bears can’t provide me with spare memory cards which i think it is. I selfishly ask for help from almarg or others here. It is beeping 3 times will not power up. I have tried reinserting the memory card. Did not work.

Re: lenco. Just an observation.

From three decks l75 i found when used in the actual speed slot, the notch for say 33.33 they run fast. Is this by design to deal with stylus drag? Idk. The swiss engineers were very smart and the motor itself a thing of beauty - to me. But it is all hooked up to a mechanical wheel. Setting the speed a little slower is a bit of a pita, but once set it runs fine other than what i noted in previous post. But all that damping in the plinth does have its effect. It is very musical just not as extended as my other deck.

Sorry for any typos - hate using this forum on a phone.
Hi Richard,

Thom
Have you considered introducing a little series R Into the power supply and scoping the motor current draw to vicariously look at stylus drag as a function of motor current draw?

Yes.  I've been wrestling with capturing the time domain of interest.  Our ears are so discerning in comparison with instrumentation, that sometimes, I feel that efforts like this are futile, and so, I put them off for another day.

Thom @ Galibier Design
Hi ct1057,

Re: lenco. Just an observation.

From three decks l75 i found when used in the actual speed slot, the notch for say 33.33 they run fast. Is this by design to deal with stylus drag? Idk. The swiss engineers were very smart and the motor itself a thing of beauty - to me. But it is all hooked up to a mechanical wheel. Setting the speed a little slower is a bit of a pita, but once set it runs fine other than what i noted in previous post. But all that damping in the plinth does have its effect. It is very musical just not as extended as my other deck.

I seriously doubt this is to take stylus drag into account.  If you think about it (and accept stylus drag as influencing speed stability) then it would exist at 33.33, 34, 45, etc.

Cheers,
Thom @ Galibier Design
Hi Pani,

I am not a TT designer but having heard many turntables (most of them are belt driven and many of them with heavy platters), less than 5% of them actually could hide their "high mass" artefacts. So, for me it is just statistics

I’ve had the same experience with most high mass turntable designs as well. It’s not my place to criticize other manufacturers, but I think everyone knows my position on drive belt materials.

I’m coming to the point that mass (when done right) is more about noise sinking than about speed stability. It’s something that I can’t test, because all of my platter damping tricks add mass (one of the ingredients is lead shot), so I can’t separate the two variables.

Cheers,
Thom @ Galibier Design