Idlers vs Direct Drive vs Belt Drive

[ddk]

That is a most interesting report, Marc. It raises many questions which I hope you or Vic can answer.

I had no idea that it takes 20 minutes for the speed to stabilize. Why is that? I had assumed that rim drive/idlers get the platter up to speed quickly and then stay that way. You write that it is up to speed in 3 seconds, but then I'm confused about why it is not stable at that point. How much does the speed vary during that 20 minutes and then how long does it take for you to confirm the speed before you play an LP? My SME takes about seven seconds for the speed to stabilize according to the blinking light on the motor controller.

Also curious is why the speed needs to be checked before each listening session after the 20 minute stabilization period. If it is stable, then why does it need to be checked? How does the system know when it is operating at the correct speed? Is the platter speed checked, or the motor speed, or both? Is there perhaps some degree of designed slippage between the wheel and platter?

I had thought that high torque motors were used to get platters up to speed quickly. If you don't listen for 20 minutes, why not use a low torque motor if the platter has enough inertia to combat stylus drag? Then it can get to speed gradually and perhaps vibration would be less of a concern.

Why does the system go out of correct speed and need to be adjusted after several days? Does vibration change the contact between the wheel and platter? And what method do you use to check for speed accuracy? Have you noticed any change in speed from stylus drag? If so, I presume you are then confirming speed while playing an LP.

Even with the fairly heavy platter on my table, it does slow down very slightly due to stylus drag, so I confirm speed with either the KAB strobe or TimeLine while a record is playing. I know ack does the same with his VPI. The only table that I have seen evidence of not slowing down with stylus drag is Halcro's Victor DD, and that video shows three arms all playing. Perhaps David's massive American Sound platter is immune also. I have met one audiophile who claimed to be able to hear stylus drag on all belt driven platters weighing less than 100 lbs so he got a heavy platter and replaced his rubber belt with magnetic tape for tape drive and reported a more stable speed.

A German designer was designing a turntable with intensional belt slip with a massive platter weighing over 100 lbs. The idea was to get the platter up to speed fairly quickly with an idler wheel and then to disengage the wheel and let the thread drive take over only occasionally slightly speeding up the platter when it slowed down, but never slowing down the platter because the thread would start to slip once the correct speed was achieved. I don't know if this table went into production.

Sorry for all of the questions, but I am curious now about the design intentions behind your Trans Fi direct rim drive table.

Never heard of motor warm up time either Peter, it doesn't make any kind sense! Regarding seeing any visual signs of cartridge drag, I can't seen any visual evidence (KAB, Ortofon or built in strobes) of it with any of my tts and that's with a 6.5 gram tracking Neumann. One caveat, I use a 0.5 kva industrial AC regenerator for all the motors.

david

 

[microstrip]

Peter, there are more similarities than differences btwn the classic Garrard/Lenco idler drive and my Salvation direct rim drive. Vic's rim wheel is button sized, of solid Delrin, and is mounted direct onto the motor spindle, which then strongly contacts the Aluminium platter against a central "stripe"/layer of Delrin (for Delrin-Delrin continuity). The 230V DC v. high torque motor then rapidly rotates the rim wheel which now drives the platter. It takes about 20mins for the speed to fully stabilise, and I allow it to run while my tubes are warming up. (...).

Porbably 230V AC? Delrin in known for low friction, I would not expect to find it in a driver wheel. How heavy is the platter?

 

[spiritofmusic]

Yes, 230V AC. Platter 9kg. Choice of Delrin I cannot comment on. Re "warm up", maybe this is a poor choice of words. The motor seems to be extremely high torque, and I would say every few records I do have to make some minimal adjustments for speed drift, normally veering on the fast side. I would never claim this is as SOTA as more overengineered products. Only w/long periods of non use, or major changes of temp/humidity does the speed need major attention. Sorry if I gave the erroneous impression that speed is all over the place within the first 20 mins.

 

[ddk]

Yes, 230V AC. Platter 9kg. Choice of Delrin I cannot comment on. Re "warm up", maybe this is a poor choice of words. The motor seems to be extremely high torque, and I would say every few records I do have to make some minimal adjustments for speed drift, normally veering on the fast side. I would never claim this is as SOTA as more overengineered products. Only w/long periods of non use, or major changes of temp/humidity does the speed need major attention. Sorry if I gave the erroneous impression that speed is all over the place within the first 20 mins.

Ok, that's normal to have some drift with changes in electricity and oil temperatures.

david

 

[PeterA]

Yes, 230V AC. Platter 9kg. Choice of Delrin I cannot comment on. Re "warm up", maybe this is a poor choice of words. The motor seems to be extremely high torque, and I would say every few records I do have to make some minimal adjustments for speed drift, normally veering on the fast side. I would never claim this is as SOTA as more overengineered products. Only w/long periods of non use, or major changes of temp/humidity does the speed need major attention. Sorry if I gave the erroneous impression that speed is all over the place within the first 20 mins.

Thanks Marc, I did not get the sense from what you wrote that the speed is all over the place within the first 20 minutes. But you did write that it was stabilizing during that time, so I asked you how much the speed was changing during that time. Is it minor and how do you know? I presume you must hear some problems because you don't listen to it during the 20 minute stabilization period, just like you don't listen as your tube amps are warming up. FWIW, I also let my SS amps warm up for about an hour before I listen.

That is curious in and of itself, but also curious is why you need to check and adjust the speed every few records even if only minimally. I don't read or know of any other turntable that needs this frequency of speed adjustments. It must be intentional on Vic's part, and I wonder what his reasoning is.

Do you know if your Delrin drive wheel is spring loaded against the rim? I wonder how the contact is maintained and if this contact is what is stabilizing or if it is the motor itself as David writes. But even there, with changes in electricity and oil temperatures, I don't hear about motors needing this constant adjustment every few records. Belts stretch and need replacement, but in your rim drive, the parts would not seem to need regularly scheduled replacement like rubber belts.

I would think that the advantage of the high torque motor and direct rim drive system is to drive the platter through any change of load from stylus drag. For this to be effective, wouldn't the contact between the drive wheel and platter need to be of high friction, i.e. no slippage?

BTW, which device do you use to check the speed of your turntable after that 20 minute stabilization period? And do you know how you motor/drive system knows when it is at the correct speed? Are there sensors on the platter or in the motor?

 

[PeterA]

Never heard of motor warm up time either Peter, it doesn't make any kind sense! Regarding seeing any visual signs of cartridge drag, I can't seen any visual evidence (KAB, Ortofon or built in strobes) of it with any of my tts and that's with a 6.5 gram tracking Neumann. One caveat, I use a 0.5 kva industrial AC regenerator for all the motors.

david

I find it easier to see evidence of stylus drag with the TimeLine than with the KAB strobe. That level of sensitivity is one advantage of using the TimeLine. It seems easier to see minute speed changes because of the laser projection over distance with the TimeLine

I can adjust the speed of my table and get the KAB strobe to look perfect, i.e. at exactly 33.333 RPM. Without adjusting anything the TimeLine will show the platter to be rotating either slightly fast or slightly slow by about 0.003%, according to someone's calculations. This is certainly below audibility for me, so it is of no concern, but the speed adjustment increments on my motor controller are 0.01% so they put the platter either slightly above or below 33.333 RPM.

This is just an aside, but it does demonstrate the different sensitivity between these two devices.

 

[spiritofmusic]

Thanks Marc, I did not get the sense from what you wrote that the speed is all over the place within the first 20 minutes. But you did write that it was stabilizing during that time, so I asked you how much the speed was changing during that time. Is it minor and how do you know? I presume you must hear some problems because you don't listen to it during the 20 minute stabilization period, just like you don't listen as your tube amps are warming up. FWIW, I also let my SS amps warm up for about an hour before I listen.

That is curious in and of itself, but also curious is why you need to check and adjust the speed every few records even if only minimally. I don't read or know of any other turntable that needs this frequency of speed adjustments. It must be intentional on Vic's part, and I wonder what his reasoning is.

Do you know if your Delrin drive wheel is spring loaded against the rim? I wonder how the contact is maintained and if this contact is what is stabilizing or if it is the motor itself as David writes. But even there, with changes in electricity and oil temperatures, I don't hear about motors needing this constant adjustment every few records. Belts stretch and need replacement, but in your rim drive, the parts would not seem to need regularly scheduled replacement like rubber belts.

I would think that the advantage of the high torque motor and direct rim drive system is to drive the platter through any change of load from stylus drag. For this to be effective, wouldn't the contact between the drive wheel and platter need to be of high friction, i.e. no slippage?

BTW, which device do you use to check the speed of your turntable after that 20 minute stabilization period? And do you know how you motor/drive system knows when it is at the correct speed? Are there sensors on the platter or in the motor?

Excellent qs Peter. I did actually find I made small adjustments to speed once a week when running my Roksan Xerxes X and Michell Orbe belt drives, so I'm kinda used to it.
Re contact of rim wheel to platter, the motor has a lever release which "leans" the rim wheel against the platter, and off one goes. The contact is a "heavy" one, and the torque is high, but I can't really comment on "slippage" because I'm unaware of any as such. I don't know if this is as primitive as one can get, but there is absolutely no feedback/servo mechanism. The motor is brought up to speed, the speed is fine tuned, the torque seems to take no prisoners in the form of stylus drag, and if there is any drift, it's over a macro period of time, maybe a week or two.
It may be my "awareness" of SQ impvts after "warm up" period is more linked to the tubes being optimal than my motor "stabilising".
Use a KAB strobe for checking.
My thoughts are that at the price point of $7k to incl arm, the performance is stellar. But I'm under no illusions throwing a lot of money to bring this concept up to SOTA performance would take what I've already got and max things out a lot more, and imho the Saskia best fits my biases.
I do need to stop talking about it 'though. I've not heard it, and noone on these forums can write any comments about it. Still awaiting the info Win promised re the tech behind the motor controller.

 

[ddk]

I find it easier to see evidence of stylus drag with the TimeLine than with the KAB strobe. That level of sensitivity is one advantage of using the TimeLine. It seems easier to see minute speed changes because of the laser projection over distance with the TimeLine

I can adjust the speed of my table and get the KAB strobe to look perfect, i.e. at exactly 33.333 RPM. Without adjusting anything the TimeLine will show the platter to be rotating either slightly fast or slightly slow by about 0.003%, according to someone's calculations. This is certainly below audibility for me, so it is of no concern, but the speed adjustment increments on my motor controller are 0.01% so they put the platter either slightly above or below 33.333 RPM.

This is just an aside, but it does demonstrate the different sensitivity between these two devices.

I just go from what I see with the strobe to listening can't say that I can hear cartridge drag either.

david

 

[Mosin]

That is a most interesting report, Marc. It raises many questions which I hope you or Vic can answer.

I had no idea that it takes 20 minutes for the speed to stabilize. Why is that? I had assumed that rim drive/idlers get the platter up to speed quickly and then stay that way. You write that it is up to speed in 3 seconds, but then I'm confused about why it is not stable at that point. How much does the speed vary during that 20 minutes and then how long does it take for you to confirm the speed before you play an LP? My SME takes about seven seconds for the speed to stabilize according to the blinking light on the motor controller...

I cannot speak directly to the characteristics of Marc's turntable, but the Saskia also takes around 20 minutes to stabilize. I suspect your SME takes much longer than seven seconds, too. (probably twenty minutes) I have reversed engineered one of those, and SME's clever bearing scheme doesn't lend itself to immediate gratification, if immediate stabilization is the goal. It is a question of degree, however, so we need to define stabilization. If "not stabilized" means wandering all over the place, both the SME and Saskia are stabilized almost immediately. If it means being off a hundredth of a percent or so in one direction, then they are stabilized more slowly. The SME is the fastest, if we use the first meaning because the Saskia intentionally ramps up slowly to prevent component wear. Otherwise, who knows?

The reason it takes awhile to perfectly stabilize is because of component and lubricant temperature. Also, tolerances in the SME and Saskia are very tight. It takes an entire day for the SME spindle to seat at the factory, and one Saskia I built took sixteen hours. Newer Saskia spindles have three flutes cut into them to further promote dynamic drag, and so now they seat quickly. The only reason Saskia uses lubricant is for dynamic drag, so it is as thick as permitted by the machining tolerances of the bearing assembly. That feature slows down absolute stabilization considerably, but it is an extremely worthwhile concession, in my opinion. However, Saskia uses the controller to speed up the motor to compensate for this characteristic during the warmup period. Also, it calibrates for the perfect recognized speed of 33.333/45/78, and holds that speed unless you tell it something different. By the way, the user can override any Saskia setting. It's your money, so if you want every record to sound like Donald Duck, go for it. A 78 will spin at exactly 100 RPM, if that's what floats your boat. Otherwise, it is as perfect to conformed standards, or more so, than any turntable out there.

The bottom line here is that all these machines become stable within a very short time period, if you are talking about a condition where music can be enjoyed.





An aside: Do not confuse rim drive with idler drive. There are some fairly important differences.

 

[ddk]

the Saskia intentionally ramps up slowly to prevent component wear. Otherwise, who knows?

Component wear?

david

 

[Mosin]

Component wear?

david

In my case, a very small idler rubber profile is used, and I don't want it squealing off the line like a 1965 Pontiac GTO.

 

[spiritofmusic]

I have used a Teres 320 'table for several years, with string, tape, and rim drive. The Teres Verus rim drive is gravity coupled by leaning its drive ring into a massive cocobolo platter. I'm vaguely recalling Chris Brady changed the drive wheel material at least once and that material along with the shape of the contact patch has an influence on sonics. Startup time to what the motor believes is correct speed takes ~5-30 seconds. The Verus controller adjusts motor speed independently of load and without servo circuits or speed sensors. This is (from what I gather from the description here) like the Trans-Fi table inasmuch as the speed of the motor and the ratio of the diameter of the drive wheel to the diameter of the platter determine platter speed, apriori. The Verus controller supports adjustment of spin-up time and motor torque.

Regardless of efforts to transform or redirect motor energy, I'm convinced any rim or idler drive will transmit some of its drive mechanism energy into the platter. Different implementations and materials of the components involved can vary the frequency, impact and audibility of this energy, but I can't imagine a drive wheel approach (on the inside or outside of the platter) where energy is not added to it as a result of the direct contact involved.

Wrt stylus drag, will that vary with groove width? Possibly being greater on, say, 45rpm LPs with serious bass excursions?

If the claim is that a high torque motor or high mass platter is able to "push through" stylus drag is that saying there is no or substantially reduced stylus drag?

Tima, from what I gather, Vic made a major breakthru when using the Verus motor in an earlier prototype. But the rim wheel spun at less than 200rpm, and was only powered by 7V DC. This was just not sufficient for ultimate speed stability, and didn't produce enough torque to contend w/severe stylus drag. Additionally the rubber O-Ring on the wheel just deformed all the time. And introducing feedback/servo just led to a smoothing/smearing of the sound.
Vic went on to use the Verus principle to design a motor from the ground up, w/a one piece Delrin rim wheel (no O-Ring), faster speed in excess of 300rpm, and beefier DC motor, and critically no servo/feedback.
This finally resulted in the magic combination of high torque to contend w/stylus drag, solid speed stability, and l/t user friendliness w/out fiddly maintenance.

Win, I know that in an earlier iteration, Vic was using a more traditional idler-type mechanism, but just couldn't make it work optimally, going to direct rim drive. Can you highlight the main points of difference btwn the two drive mechanisms?

 

[spiritofmusic]

That's true Keith. Not 24/7, although that would be an interesting concept, and people do run their motors continuously. But, in an extended listening session of a few hrs, the platter will be revolving continuously (w/that 20 min "warm up" period), even if I stray to playing a cd or two. Because the lps are not secured down, in effect sit on "soft" points w/no vacuum hold down/periphery ring/clamp, scooping lp's off to change sides/change records is a doddle.
I was starting to feel a little anxious re this period, but Win has put my mind to rest that even bleeding edge SOTA tech is prone to the same vagaries.
Strobe measurement and speed adjust every week or two/w.major change of temp or humidity/w.long lay off.

 

[PeterA]

I cannot speak directly to the characteristics of Marc's turntable, but the Saskia also takes around 20 minutes to stabilize. I suspect your SME takes much longer than seven seconds, too. (probably twenty minutes) I have reversed engineered one of those, and SME's clever bearing scheme doesn't lend itself to immediate gratification, if immediate stabilization is the goal. It is a question of degree, however, so we need to define stabilization. If "not stabilized" means wandering all over the place, both the SME and Saskia are stabilized almost immediately. If it means being off a hundredth of a percent or so in one direction, then they are stabilized more slowly. The SME is the fastest, if we use the first meaning because the Saskia intentionally ramps up slowly to prevent component wear. Otherwise, who knows?

The reason it takes awhile to perfectly stabilize is because of component and lubricant temperature. Also, tolerances in the SME and Saskia are very tight. It takes an entire day for the SME spindle to seat at the factory, and one Saskia I built took sixteen hours. Newer Saskia spindles have three flutes cut into them to further promote dynamic drag, and so now they seat quickly. The only reason Saskia uses lubricant is for dynamic drag, so it is as thick as permitted by the machining tolerances of the bearing assembly. That feature slows down absolute stabilization considerably, but it is an extremely worthwhile concession, in my opinion. However, Saskia uses the controller to speed up the motor to compensate for this characteristic during the warmup period. Also, it calibrates for the perfect recognized speed of 33.333/45/78, and holds that speed unless you tell it something different. By the way, the user can override any Saskia setting. It's your money, so if you want every record to sound like Donald Duck, go for it. A 78 will spin at exactly 100 RPM, if that's what floats your boat. Otherwise, it is as perfect to conformed standards, or more so, than any turntable out there.

The bottom line here is that all these machines become stable within a very short time period, if you are talking about a condition where music can be enjoyed.





An aside: Do not confuse rim drive with idler drive. There are some fairly important differences.

Thanks Win, that was very informative. My question now is: Can one hear a difference during this 20 minute stabilization period? Marc seems to imply that he can because he does not listen during this time. I may check to see if my Sutherland TimeLine can show a speed variation between immediate start up and half an our later. I would think that component and lubricant temperature would not change enough to matter when stopping the platter to flip over a record. Marc writes that he keeps the platter spinning and I have read many other people do the same.

Could you elaborate on your statement about the differences between rim and idler drives?

 

[spiritofmusic]

Keith, well when the Monaco is like a teenager w/OCD flitting about to potentially alter speed every 1/4000 of a sec to smooth an average excellent speed stability , the Salvation, Teres and Saskia etc are taking a little time to get to a point where excellent speed stability is the norm w/no "hunt and correct" micro management needed.
If you feel the oil in the Monaco bearing in particular whether warm or cool has no bearing on speed stability, that's ok too. But I find it a little hard to believe the GP is on the money after 2s, all day long, any day, any season.
I'm still more a fan of the kind of design tech that has to produce a thunderous amount of torque to drive on a heavy platter thru stylus drag, bearing friction, ambient conditions, than the type that is light and fleet, needing minimal energy to get to destination, but then having to dance on it's toes all the time to manage perfect balance, like the Monaco or Brinkmann Bardo.
Remember I'm a fan of the Monaco, you don't have to convince me of it's merits. But it may be oversimplistic to portray it's uber prowess in this way.

 

[spiritofmusic]

Peter, I do listen to music quite often during the "prelude", just not intently. I'm one for early morning sessions, and cd as well as lp initially can sound just a TAD ropey, even w.my radial main/8kVA balanced power transformer knocking juice into shape going into my rig. I actually notice intermittent speed variation needing addressing every 1-2 wks, and it seems to be at the start rather than end of a session. I have to say, ever since I modded the tt to magnetic bearing, these variations are less, and hence it may be more down to the tt itself than the motor/drive. Now mainly solved.

 

[PeterA]

Keith, well when the Monaco is like a teenager w/OCD flitting about to alter speed every 1/4000 of a sec to smooth an average excellent speed stability , the Salvation, Teres and Saskia are taking a little time to get to a point where excellent speed stability is the norm w/no "hunt and correct" micro management needed.
If you feel the oil in the Monaco bearing in particular whether warm or cool has no bearing on speed stability, that's ok too. But I find it a little hard to believe the GP is on the money after 2s, all day long, any day, any season.
I'm still more a fan of the kind of design tech that has to produce a thunderous amount of torque to drive on a heavy platter thru stylus drag, bearing friction, ambient conditions, than the type that is light and fleet, needing minimal energy to get to destination, but then having to dance on it's toes all the time to manage perfect balance.
Remember I'm a fan of the Monaco, you don't have to convince me of it's merits. But it may be oversimplistic to portray it's uber prowess in this way.

Marc, I know my SME takes longer to reach operating speed during the winter. As Win wrote, tolerances are extremely tight and the component and oil temperatures vary more with the season.

 

[spiritofmusic]

Yes all day long ,winter or summer,because the Monaco controls the speed of the platter, which the record is attached to, ( screw down clamp over a Sorbathane washer) .
Keith.

I do find it fascinating on WBF that while most of us debate designs endlessly, strongly supporting our chosen designs, we don't just reduce things to simple black and white all the time.
You don't do the Monaco and your sponsorship of it any favours Keith by saying it's just rock solid out of the box/any time/any place etc etc. We have designers and users here w/uber engineered tt's all admitting there are interesting design choices, but consistency is hard to get perfect, can take time and application.
But of course you say the Monaco, of all the tt's in existence, just performs w/no variation in any condition of which there are many that mitigate against consistency.

But if the Monaco is the model of consistency down to 0.001% speed accuracy 997 times out of a 1000, every 1/4000 of a second, in effect absolutely at least to 0.001% 3988 times out of 4000 equally spaced measurements every second, all within seconds of turn on, morning, night, winter, spring, summer, autumn, whether the vinyl is warped, whether it's hot, cold, humid, not humid, no matter what weight of cart one uses, and provides this uber performance absolutely 100% of the time, well I'll be AMAZINGLY impressed.
Just why would we even consider buying another high end tt?

 

[spiritofmusic]

I'm going to draw down on only mentioning my Salvation, the Monaco and the Saskia, otherwise this thread will just get into a blind alley.
I'm really surprised, and disappointed, that other than me and Keith, noone is commenting on moving to dd/idler/rim from belt.
Maybe Audio Asylum or Pink Fish are the forums for these!
My contention remains that I've made the right choice, since I deeply believe high torque/high inertia combined w/good speed stability lends that extra edge of dynamics to the other presentations I'm more used to, and I'm putting this down to the ability to keep pushing thru stylus drag and maintain consistency over shorter periods of time, w. l/t speed drift much less of an issue audibly.

 

[DaveyF]

Marc, I think there are numerous variables, all highly important in the playback of vinyl. For example, the type of suspension system that the TT utilizes...or lack of. The motor and type, the arm to plinth fixing mechanism, the drive system and on and on. There are pluses and minuses to all types of drive system. Personally, I prefer a belt drive with suspension...which is why I am a 'Linnie'.
If one listens to the various motor control systems that are available for the Linn, there is a considerable difference in SQ between the entry level Majik system, the upgraded stand alone Lingo system and finally the Radikal D system. Like I said, everything matters---Improve speed control and the SQ increases. Improve isolation, same thing, etc, etc.