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

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

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

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

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

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

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

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 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

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