Idler wheel "magic"...

[Daniel Walte]

was the excessive noise floor in most cases caused by the platter bearing? Noise can come in many forms . Specify hiss, rumble , howl or what :thmbsp:

The reason I ask is I had an issue with my dual drive when I first bought it with the table bearing? And by question mark I mean there is no bearing. A wadded grease pack is what they used.Cleaned all the old stuff out and I have done it a different way 5-20 synthetic in new wadding. It was scraping before and that took care of the scraping.

 

[Pio1980]

In most cases the noise floor would be primarily rumble from the idler. In your case it was a fouled unlubed bearing grinding away. Idler changers also are prone to rumble from the annular ball thrust bearing which is one reason why they are generally shunned by advancing audiophiles.

 

[dnewma04]

Rumble from the idler and very noisy motors, in general. A garrard 301, for instance, has a very noisy motor.

Mark Kelly did some nice noise tests on various motor types a few years back.

The 3 phase motor is a Maxon EC 3 phase motor. The Thorens and Landis and Gyr are the standard single phase AC Sync motors you find in most standard belt drives.

 

[Bigerik]

So where would the old Pabst motors fit in to the chart, Dave?

 

[marc mc]

The issue of rumble keeps coming up with discussions about idlers. I thought I would add another quote from Arthur on this issue since sound floor is his obsession.

My most important observation is that the Lenco did not fail in those areas where I originally expected it to fail. Based on my prior experiences with idler-drives, I was concerned that I may hear "rumble", and even if the rumble was no longer itself directly audible, I still expected the higher sound-floor of the Lenco to obscure low-level musical information. As an audiophile whose entire system was designed to have the lowest sound-floor theoretically possible, any component that noticeably compromises this area would be unacceptable to me, regardless of its other virtues.

As it turned out, the Lenco's sound-floor was basically as low as the Forsell's (which has an air-bearing platter). In fact, I couldn't distinguish them. Since the Forsell had the lowest sound-floor I ever experienced, the Lenco's (highly welcome) achievement in this area is both surprising and unexplainable (at this time). In any event, with this highest of hurdles successfully breached, the next challenge was the Forsell's neutrality and/or lack of coloration/character. Once again, to my surprise, the Lenco matched the Forsell in this critical area (especially for those serious audiophiles who don't want a relentless "editorializing" or "bias" in what they hear). Further, in the area of transparency, the two turntables were also indistinguishable to me. In short, the two turntables sounded very similar in "the basics", which is something I hadn't experienced before at this high level.

Marc mc

 

[dnewma04]

They were extraordinarily inefficient motors (6%), but I've never seen noise measurements. My ROK motors gets seriously hot after it's been running a while.

If I had to guess, I'd say more similar to a 301 than to a modern AC Sync motor.

 

[Pio1980]

As I mentioned quite a ways back, re the Sutherland timeline, there have been many
TT tested and some brand new high dollar tables were not even able to run without
a stylus and keep proper speed.
Lets say there was some head turning at the results.
Without mentioning any brands, some of the TTs that were able to show No speed deviation with or without a needle in a grove were Vintage models running very
sophisticated speed control circuits.
Again can one hear the deviation?

Brilliant device, that! Wish I'd thot of it. It can definitely show drag and DD modulation correction jitter in real time. I'm guessing the TTs without speed deviation were the 'better' DDs, possibly Denon and Sony rim-reading quartz-clocked PLL TTs and the like.

 

[mfrench]

The issue of rumble keeps coming up with discussions about idlers. I thought I would add another quote from Arthur on this issue since sound floor is his obsession.

My most important observation is that the Lenco did not fail in those areas where I originally expected it to fail. Based on my prior experiences with idler-drives, I was concerned that I may hear "rumble", and even if the rumble was no longer itself directly audible, I still expected the higher sound-floor of the Lenco to obscure low-level musical information. As an audiophile whose entire system was designed to have the lowest sound-floor theoretically possible, any component that noticeably compromises this area would be unacceptable to me, regardless of its other virtues.

As it turned out, the Lenco's sound-floor was basically as low as the Forsell's (which has an air-bearing platter). In fact, I couldn't distinguish them. Since the Forsell had the lowest sound-floor I ever experienced, the Lenco's (highly welcome) achievement in this area is both surprising and unexplainable (at this time). In any event, with this highest of hurdles successfully breached, the next challenge was the Forsell's neutrality and/or lack of coloration/character. Once again, to my surprise, the Lenco matched the Forsell in this critical area (especially for those serious audiophiles who don't want a relentless "editorializing" or "bias" in what they hear). Further, in the area of transparency, the two turntables were also indistinguishable to me. In short, the two turntables sounded very similar in "the basics", which is something I hadn't experienced before at this high level.

Marc mc

^^
It's the knife-edged wheel. I used one in my Presto Pirouette T-18 repowering, driveline redesign, along with a DC motor.

 

[mfrench]

Brilliant device, that! Wish I'd thot of it. It can definitely show drag and DD modulation correction jitter in real time. I'm guessing the TTs without speed deviation were the 'better' DDs, possibly Denon and Sony rim-reading quartz-clocked PLL TTs and the like.

The KAB device provides you with formulations to determine the percentage of variance. The TimeLine Strobe only shows that you have variation of speed, without anyway to determine what percentage.
For the extra $300 that the Timeline cost, you can get a pretty decent cartridge; ($400 Timeline strobe vs $100 for the KAB strobe).

 

[Pio1980]

The discussion seemed to be whether the variance actually occurs and the device proves that it does, at a boutique price. I'd like to see an add-on quartz clocked 'disco-ball' type strobe that could show drag variance and jitter in real time at reasonable cost.

 

[dnewma04]

I think the variance of concern is the variance between a dynamic part of a track and a less dynamic part, not a speed variation at the time of a needle drop.

 

[gusten]

The discussion seemed to be whether the variance actually occurs and the device proves that it does, at a boutique price. I'd like to see an add-on quartz clocked 'disco-ball' type strobe that could show drag variance and jitter in real time at reasonable cost.

The devise doesn´t prove anything of the sort, at best it would show there is a frictional drag, which I don´t think many would argue against. As I am a skeptical guy when it comes to statements in audio, it might even show something else.
gusten

 

[Daniel Walte]

step down transformer came today. I got lucky no ill humms or static. What it did do is make a extraordinary turntable into a out this world extraordinary turntable. I wouldn't pay 10 cents for a 2 grand table to replace it. Thanks to all for the helpful advice on this thread. Time I move on, all take care!

 

[totem]

The KAB device provides you with formulations to determine the percentage of variance. The TimeLine Strobe only shows that you have variation of speed, without anyway to determine what percentage

There has been a formula made that gives you a percentage measurement
for the timeline. Provided by an Agon member.

No I do not own one, but products like this and a few other $$ seldom used
tools only make sense to me if they can be shared by a local group to help
offset the cost, at least in regards to the funds I have available.

 

[nashvillebill]

There is NO WAY the stylus pressure can slow down a motor. I've run the torque calculations due to the stylus friction, it is so insignificant it isn't funny.

Motor bearing drag? That definately could be an issue. Platter bearing drag? Also could be an issue.

But stylus pressure? Nope. (Say a 0.1 coefficient of friction, which is very very conservative. 2 grams tracking force, also conservative. Maximum radius of record is 6 inches. This yields 0.04 inch-ounce of torque required. The motor bearing frictional torque dwarfs that number.)

 

[totem]

nashvillebill

Not to beat this topic to death, but with the timeline it has been shown
that stylus drag affects are real.

At least on TTs that have failed.

Further reading on the specifics on Agon.

 

[nashvillebill]

Maybe to somebody that doesn't have an engineering degree.


I call BS.

 

[dnewma04]

There is NO WAY the stylus pressure can slow down a motor. I've run the torque calculations due to the stylus friction, it is so insignificant it isn't funny.

Motor bearing drag? That definately could be an issue. Platter bearing drag? Also could be an issue.

But stylus pressure? Nope. (Say a 0.1 coefficient of friction, which is very very conservative. 2 grams tracking force, also conservative. Maximum radius of record is 6 inches. This yields 0.04 inch-ounce of torque required. The motor bearing frictional torque dwarfs that number.)

Drag isn't a bad thing with many motor types to produce more stable speed. The key is that you want the drag consistent.

 

[dnewma04]

Maybe to somebody that doesn't have an engineering degree.


I call BS.

Good grief.

 

[nashvillebill]

Look the drag from the stylus is 0.04 in-ounce!!

The drag from the platter bearing is at least 10 times that, maybe more. Then there's the motor bearing drag, and the compression/rebound of the rubber idler wheel, or the rubber belt. Those numbers are not constant. Any variation in those factors far exceeds any variation from the stylus dragging changes.