advertisement


Is this the best tonearm in the world?

My platter weighs around 15 kilos . I don't know what the speed the stylus is going at the start of a record ( if you see what I mean ? ) but I can't think that the 2.5gm downforce is going to make much of a dent in the speed.
 
You run 2.5g? Jesus....

I'm sure someone suitably mathsy will be along soon Joe, I'd imagine the energy of your rotating platter is a good 100,000 greater than the peak +/- of stylus drag.
 
You run 2.5g? Jesus....

I'm sure someone suitably mathsy will be along soon Joe, I'd imagine the energy of your rotating platter is a good 100,000 greater than the peak +/- of stylus drag.

Morning Si ...

2.5g is what Denon recommend for the tracking force of the 103r that I am running at the moment. They are robust old things **, something to do with their broadcast heritage. ?

As to stylus drag....I laugh in the face of it.

** I also have an Audio Technica AT33PTG /II which when I received it I thought it had no cantilever on it....it is so fine, so thin compared to the old 103.
 
2.5g seems to be somewhat of an average for LOMCs. I have the EMT (Tondose MRB), the AT (AT33Mono) and the Denon (DL-A110) all running at around 2.5 grams in line with manufacturers recomendations.

At least it is not the 4.0 grams needed for the SPU #1.

I run a somewhat rare combination of a high mass platter (actually two platters one sitting in the other) with a combined mass of 18.5 kg, and a drive system relying on a high torque BLDC motor connected with a belt to a high mass flywheel driving the outer rim of the platter via direct coupling. Sort of an inverted TD-124 drive, if the Thorens had a very heavy platter and the idler was a massive flywheel.

Having said that, stulys drag is noticable, but mostly immediately after lowering the tonearm in the groove. The motor controller is quite sensitive, as I measure the speed between 4 and 12 times per rotation. With the EMT on a SME 3012, lowering the stylus an immediate drop to the speed can be seen, either on the controller screen, or on a connected oscilloscope running a test signal. It seems to correct gracefully and quickly - so I cannot say it does much to the perception of music.
 
2.5g seems to be somewhat of an average for LOMCs.

I'd say that was a little high; certainly compared to 2 Lyras, Shiraz, Karma, Benz Ebony, Trandfig.Proteus and 2 x Koetsus (I may have missed one or two ;)). The Lyras are about 1.75g, whereas the others varied between that and 2g (max recommended).

Having said that, stylus drag is noticeable, but mostly immediately after lowering the tonearm in the groove. The motor controller is quite sensitive, .....
.

You've raised a good point, in that many (most?) speed controllers will compensate for any stylus drag after a few revolutions. I'm not sure about this, but my Wave Mechanic takes a little time, but that's prob. the platter mass and low-torque motor.

As Simon and Joe suggested above, it's all of little consequence unless you can actually hear musical lethargy !:)
 
Having said that, stulys drag is noticable, but mostly immediately after lowering the tonearm in the groove. The motor controller is quite sensitive, as I measure the speed between 4 and 12 times per rotation. With the EMT on a SME 3012, lowering the stylus an immediate drop to the speed can be seen, either on the controller screen, or on a connected oscilloscope running a test signal. It seems to correct gracefully and quickly - so I cannot say it does much to the perception of music.

That is very much what I’ve observed over the decades with various turntables. I’m struggling to find the right words to describe what I think is going on, but my suspicion is the whole thing is quite ‘fluid’ and there is even some ‘bounce’ in some scenarios, albeit with some damping. I’d certainly argue that anyone who thinks any deck goes round a a perfect 33.3rpm all the time is mistaken. There will be subtle ebbs and flows relating to drag and the various counter-forces (motor torque, belt compliance, rotational mass etc). This is unavoidable, just the nature of any drive system on anything (e.g. applies to cars, lathes, food mixers, anything). Everything will react to load to a varying degree.

The question is how best to correct for it. I guess this is the place to put the old and I suspect flawed 1970s argument against direct drive in. The suggestion was that as they (depending on control system) react dynamically to load they constantly hunt and over-correct and are therefore always “wrong”. Hands up who had that lecture from a Linn dealer?! My view given the really good direct drive turntables are very good pitch wise is that this isn’t true on a well designed system where torque and rotational mass have been well thought through. It is also interesting to note some modern direct drive decks, e.g. the 1200G, do have a configurable torque setting, and it does sound different.

We definitely need to think about belt compliance too. If one takes a cheap lightweight belt drive deck, say a Dual 505, I don’t think there can be much doubt that there is potential for some ‘spring’ in the drive system as it has a compliant belt and a comparatively low rotational mass. That is going to react differently to drag than say a Nottingham Dais, or a high torque deck like a 301 or SL1200.

This one really isn’t nailed down to my mind. I suspect there is a lot more going on than some might like to think.
 
Speaking of 'high-mass' turntables, I visited this chap's workshop/store a few times back in the day (once to have a used Systemdek IIX900 serviced) and in my limited experience of vinyl his flagship record players are as top-tier as any.

He is crazy about race cars and would compare the tiny improments to his turntable designs to the adjustments in F1 aerodynamics and tire pressure that can lead to shaving a couple of 1/10 second off your lap time and get you into pole position.

The interesting thing is that they're comparatively affordable, some would say because he's not yet been found by big-league industry pundits the likes of Mic Framer...
This model below was being sold for €50k in 2019:

rui-borges-pendulum-ii-plattenspieler-58056.jpg


https://www.ruiborgesturntables.pt/index.php/portfolio/project-2

But his name is not shilled about by the top magazines and the German distributor is struggling to sell it:

https://www.klangloft.de/phono/?p=1&o=7&n=12&s=18
 
The Korf Audio blog has a series of recent posts on turntable drives (belt drive, idler, direct drive). What's interesting is that no drive technology is free of serious problems. Direct Drive is theoretically closest to the ideal but even that technology is beset with difficulties.

http://korfaudio.com/blog

The turntable designer I mentioned in the post above yours agreed with you, and said that having tried the best motors available he still couldn't get identical performance to belt drive.
 
The Korf Audio blog has a series of recent posts on turntable drives (belt drive, idler, direct drive). What's interesting is that no drive technology is free of serious problems. Direct Drive is theoretically closest to the ideal but even that technology is beset with difficulties.

It is a really interesting site. The bits I’ve read certainly add depth and detail to what I think is going on. I’ll keep it open until I’ve read the whole thing.
 
This from the Korf blog on the difference in energy between a Shure M97 (high compliance MM) and Denon 103 (low compliance MC) is fascinating. The difference in energy pumped into the arm is very clear to see, and to be honest exactly what I’d expect. Great to see it on a graph though!

PS I do think there is a strong case for high compliance MM carts that have to my mind been revised away by fashion and groupthink. I’ve a lot of time for them and would like to see a bit of a revival. If one focuses on the job to be done it is a highly logical approach IMHO.
 
It is a really interesting site. The bits I’ve read certainly add depth and detail to what I think is going on. I’ll keep it open until I’ve read the whole thing.
There's a fascinating paragraph at the end of part iv. First he shows a graph that shows speed distribution in late 1970's turntables — how many times a given momentary speed was measured over a given period of time. The speed was taken 5000 times a second while a pop music LP was playing. Then he writes:

"DD's momentary speed wanders over a much wider range, having at least 2 distinct peaks. The belt driven turntable has the correct speed almost twice as often—despite its much worse wow and flutter specification."

The fascinating implication is that 40 years ago belt drives might still have been the least wrong implementation. But with the advance in modern electronics/computing, DD designers might now have technology to address this. Alex Korf seems to smell an opportunity.

It reminded me of Onkk - an expensive, fledgling British DD turntable of a few years ago (seems to have gone quiet). Like OMA, Onkk's designer (Paul Beckett) was talking about how tracking speed continuously at the platter was the key to his turntable's performance.

 
I'd say that was a little high; certainly compared to 2 Lyras, Shiraz, Karma, Benz Ebony, Trandfig.Proteus and 2 x Koetsus (I may have missed one or two ;)). The Lyras are about 1.75g, whereas the others varied between that and 2g (max recommended).

I stand corrected. What I should have made very clear (in hindsight) is that I use new production, but very much ancient design "transcription" cartridges. VTF of >3 grams is not a rarity there.

There will be subtle ebbs and flows relating to drag and the various counter-forces (motor torque, belt compliance, rotational mass etc). This is unavoidable, just the nature of any drive system on anything (e.g. applies to cars, lathes, food mixers, anything). Everything will react to load to a varying degree.

That is more than certainly true, at least in my case, as shown here (a polar plot of speed fluctuations for 40 full rotations, a total of 160 measured data points, for each nominal speed):

EIFLqnp.jpg


I have a lot of flexibility to experiment easily. With the arrangement, I can vary belt tension and idler pressure just by moving components around - difficult to do in a closed system. That saves me a lot of hassle, but it also shows how difficult it is to maintain precision and stability in a production line without excessive complications which inevitably either (1) cost exponentialy, (2) degrade the sound or (3) both.

The Korf Audio blog has a series of recent posts on turntable drives (belt drive, idler, direct drive).

Korf make a lot of very good points, and are very generous with sharing their knowledge. I am a bit wary lately with their interpretation of their results as it plays into what I feel is a very subtle sales pitch. It inevitably leads to a product that fixes the issues determined by their interpretation. I may be mistaken, but it seems to have happened three times in a row, so there is that. Of course, one cannot forget the raw information they willingly share, so most certainly a win for the hobby.

Like OMA, Onkk's designer (Paul Beckett) was talking about how tracking speed continuously at the platter was the key to his turntable's performance.

I stand by that approach. It is very sound logic to me. Measuring speed at the motor (via encoders) is certainly easier to implement, but in my head is never correct unless a rigid coupling exists between motor and platter. And it almost never does - some slip and/or misplacement is inevitable. Even NAB standards (the paper from 1964) clearly specify measuring speed on the platter to determine compliance within specified tolerances. They do, however, allow for a tolerance of 0.3% on the playback side, so there is that too.

Measuring speed 5,000 times a second, meaning 9,000 times per revolution at 33.(3) seems a bit ludicrous though - but it may have been crucial to the designs of 70s DDs.
 
Korf make a lot of very good points, and are very generous with sharing their knowledge. I am a bit wary lately with their interpretation of their results as it plays into what I feel is a very subtle sales pitch. It inevitably leads to a product that fixes the issues determined by their interpretation. I may be mistaken, but it seems to have happened three times in a row, so there is that. Of course, one cannot forget the raw information they willingly share, so most certainly a win for the hobby.

I have to admit I was initially trying to figure out what they were selling, though the findings on a whole range of topics are really interesting and exponentially more intelligent than the usual guff we are presented with in this industry. Interesting to compare what I view as really interesting research of the Korf site with what I view as pure sales pitch from OMA.

I found the content regarding turntable drive systems very well articulated and it aligns remarkably closely with my own gut feelings and unsubstantiated thought. It makes sense and his plus/minus for each drive type are roughly what I’d attempt to articulate.

As stated above the site also reinforces my view that high compliance moving magnet cartridges have some advantages. I do not accept they are inherently inferior to MC even if market forces have currently positioned them as such. There is clearly room for development/reevaluation here.
 
Korf make a lot of very good points, and are very generous with sharing their knowledge. I am a bit wary lately with their interpretation of their results as it plays into what I feel is a very subtle sales pitch.
Korf admits that there are things he isn't sharing, so the whole blog needs to be read as a commercial exercise, but a very open one, as you say.

Measuring speed 5,000 times a second, meaning 9,000 times per revolution at 33.(3) seems a bit ludicrous though - but it may have been crucial to the designs of 70s DDs.
This is the fascinating bit: Korf is measuring thousandths of second, Onkk were talking about speed correction in milliseconds, and OMA (see 28:20 onwards in the video below) are taking about the threshold of audibility being in the millionths of a second. It's all salesmanship, but they are all saying similar things.
 


advertisement


Back
Top