1. Things you need to know about the new ‘Conversations’ PM system:

    a) DO NOT REPLY TO THE NOTIFICATION EMAIL! I get them, not the intended recipient. I get a lot of them and I do not want them! It is just a notification, log into the site and reply from there.

    b) To delete old conversations use the ‘Leave conversation’ option. This is just delete by another name.
    Dismiss Notice

Is this the best tonearm in the world?

Discussion in 'audio' started by G T Audio, Mar 9, 2023.

  1. Paul R

    Paul R pfm Member

    It's a shame that data is from the 60s with 60s carts, stylus profiles and tracking weights using test discs with constant (sic) velocities. Very interesting though.

    I think we need measurements on real discs played by typical stylii. Try and repeatably see dynamic drag and ideally any consequent dynamic wow.
  2. InSides

    InSides pfm Member

    It makes sense, in a way, as both stem from a similar origin.

    The initial Onkk relied on a (fully) reworked Audio Technica DD motor, which is in a way, let's put it subtly, "an homage" to the 1970's Technics products. I have no way of knowing what is the technology inside the OMA, but I doubt there are many more ways to slice a cake with a DD motor, not in some way experimented by Matshushita already.

    I would be very interested to conduct a similar research - especially when it says in the report "...developed a simple method... ...without the need for a special equipment." Is there a longer version of the report where the method is elaborated upon?
  3. Tony L

    Tony L Administrator

    I love this quote from the Korf direct drive page:

    Back in 1970s, generating a clean synchronised sine current was very hard. Most manufacturers used a simple trapezoidal ("on/off") commutation instead.

    This is a bit like ordering ice cream and being served herring.

    I get the impression things have moved on a long way now. IIRC all modern Technics use a high resolution digitally sampled sine wave as the control source now. Obviously impossible back in the ‘70s.

    PS Whilst we are on the subject of drive systems I’ll drop this video in as I think the Thorens 124 solution was fascinating:

    The negative is it is over-complicated, and that complexity inevitably generates noise compared to the simplicity of either belt or direct drive. The plus is just how much torque and motor speed step-down. It makes for a very powerful and smooth drive system as the 1450 rpm motor is first geared down by the belt, and then again by the step-pulley, each time reducing the effect of cogging and increasing torque. Assuming everything is clean it can get the 4.5kg cast iron platter up to speed in just one revolution. Not as fast as a SL1200, but not far off, and it is a far heavier platter. There is very little compliance in this drive system.
  4. Paul R

    Paul R pfm Member

    You're running a synchronous motor. The speed will only change (unless you stall it of course) due to belt stretch or slip. But it could still wow dynamically under a changing load.
  5. Paul R

    Paul R pfm Member

    tuga likes this.
  6. Paul R

    Paul R pfm Member

    Presumably in the 1981 AES Journal article? Need a member to do some reading.

    I did a very crude experiment last year with a spare LP12 and a DC motor. Using an ammeter you can measure the current required just to turn the deck, with a stylus playing an outside groove and inside groove. All differ as expected. The problems though were irritating. I have an Origin Live pulley that is wrongly formed. The speed wandered up and down cyclically due (I infer) to the belt wandering up and down the pulley's camber. The ammeter has a significant impedance, so extra load reduces the voltage and speed even more than naturally due to the motor. However if these are compensated for you have a direct measure of the power change when the stylus is lowered. Hence the drag.

    I did show though that a single magnet near the platter added drag at a level much greater than that produced by the stylus.
    tpetsch likes this.
  7. Tony L

    Tony L Administrator

    Acting as an eddy-brake? I have to admit I have no understanding how they work on non-ferrous metals. I don’t get it at all. I only know of them at all due to the speed controls on Garrards and 124s.
  8. ssimon

    ssimon pfm Member

    This discussion proves that we like the science to prove what we like to hear. The Luka Bop founder(in a vid earler in the thread) had it it right when he said he preferred the sound of the idler drive (I think it was a Thorens) so would not change. I have had mainly belt drive (Linn, Rock, and Brinkmann) but I prefer the sound of my direct drive Grand Prix which just makes music sound more alive.
  9. IceG

    IceG pfm Member

    More off a completely off-the-wall (or perhaps on-the-wall) approach courtesy of a recent post in another audio forum.

    Thought about starting a separate thread but the tonearm and rotation characteristics seemed to fit here.

    The Wheel turntable:
    Nero likes this.
  10. Paul R

    Paul R pfm Member

    Exactly. Not sure I have much intuition on how they work. But moving a conductor through a magnetic field generates a current, and a current produces a magnetic field, and due to conservation of whatever those fields are opposed, hence brake. It's a bizarre effect, it seems much stronger than it should be. There's probably Youtube of dropping magnets through tubes. And Veritasium has a nice example in his latest, although that's not exactly a magnet with an audiophile purpose.

    I don't know where to start with the maths but I did wonder about whether it was possible to produce an eddy current drive operating directly on a non-ferrous platter. I don't think there's been a direct drive mod for an LP12 yet and it would be quite raddical.
    Tony L likes this.
  11. Tony L

    Tony L Administrator

    Following on from the Korf blog on direct drive control circuitry I had remembered correctly and Technics are now using ROM-based sine wave samples, explained here on their 1200GR page. To my mind this makes way more sense than any kind of feedback loop as it is a pitch-perfect wave of precisely the waveform the motor needs, so no need for any ‘hunting’ assuming the torque, which is very high, is sufficient for the job in hand. It just makes sense. I assume pitch control is achieved by altering the playback frequency of the digitally stored sine-wave, i.e. just like any sample-based keyboard. It likely means direct drive is ‘solved’!
  12. sq225917

    sq225917 Bit of this, bit of that

    All things being equal, ill still take an AC motor driving a heavy platter through very thick oil fed from a high quality regenerated sinewave. No motor cogging due to high load from bearing and cart drag gets swamped by viscous drag in the bearing rendering it moot.
  13. Darmok

    Darmok "In Lation, Trans Lost."

    Fascinating thread.

    I beg to differ...

    It was Fleming and "Lee De Forest" with the introduction of the third electrode added to use as a "Control Grid" inside an evacuated glass valve light bulb to prevent / attract away the soot burning off the light bulbs filament, that caused a darkening / coating the inside of the evacuated glass envelope and accidently created the Triode and with it the Diode.

    From then on started the Electronic Communication Industry.

    The first ever possible control of the free flow of Electrons.

    Secondly, it was the 1951 discovery / invention of "William Shockley" and the use of Semi-conductors "Germanium Transistors."

    William Shockley - an overview | ScienceDirect Topics

    The "Cat Whisker," clever fellow, imho.

    Then NASA, that was only possible because of the two previous World changing events via Fleming and then later Shockley.

    Back on topic, the best sounding tone arm to date to my ears was the Decca Unipivot c/w the magnetic bias clipped on to the tone arms pillar, the tone arm was fitted with a Decca SC4E.

    All of which was mounted on a Garrard 401, flush strobe light version, mounted on a quarter inch thick cast iron slab, cut outs to fit in the 401, no plinth just a massive motor board, I wish I still had it.
  14. Perart1

    Perart1 pfm Member

    There is a tonearm that has very few adjustment that can be made, simple design, and ignores all the received wisdom associated with the design and set up of a tonearm. The Viv. This is a plonk and play tone arm that ignores everything i have been taught about tone arms. I had the pleasure of having the 10" and the 7" on an extended loan (no I am not a reviewer) and used them both on my Verdier. Quite remarkable . They hosted the Dynavcector X1-t, IO-m and Allaerts carts. I eventually preferred the 7"! Incredibly musical; no distortion on the inner grooves of large classical orchestral music, wonderful tone on operatic voices where you could hear how the singer was controlling the note.

    nmtjb likes this.
  15. Beobloke

    Beobloke pfm Member

    Be careful of taking too much advice from that. He did a reasonable job on the belt and idler theory, but clearly doesn't know much about direct drives.

    The idea that the electronics industry has only been able to generate a clean, low distortion sine wave in the last few years is particularly laughable.
    sonddek likes this.
  16. Tony L

    Tony L Administrator

    You are obviously correct on the theory as every test oscillator or classic analogue synth will testify, though whether ultra-clean sine-wave oscillators ended up in direct drive turntables is a whole other question. He certainly found something quite janky as an example.

    The fact Technics have moved to ROM based samples in their current direct drive turntables right up to the top SP1000 suggests they feel this is a better approach. The way I read the Korf blog posts he is discussing it without any knowledge of these new techniques and as such is arguably a little dated.

    As I understood it the issue was as much the necessity for a feedback loop as it was the sine-wave source, and I suspect that is a good argument. Again this makes the current Technics system a potential game-changer as the pitch of the sample is set in stone, it is accurate, therefore I don’t see any need for any feedback loop at all. Brute-force torque and rotational mass locked to a totally accurate digital control source should render the whole back and forth of a feedback loop obsolete, surely? Even more so as the sample wave shape can theoretically be whatever is most suited to driving the specific motor in question. It strikes me as a potentially significant development in direct drive technology.
    sonddek likes this.
  17. Beobloke

    Beobloke pfm Member

    Don;t get me wrong, Tony, I agree that the new Technics methodology is certainly a big improvement on some of the rather more hair-shirt approaches taken in the 1970s! However, even precision software control isn't new - Vestax were controlling their DJ turntables' direct drive motors using 32 bit CPUs over 15 years ago.

    I'm also curious as to why he sees fit to mark down one of the negatives of direct drive as "Most existing implementations subjectively underwhelming"

    I'd be curious to know which sample decks he bases this statement on.
    sonddek likes this.
  18. Tony L

    Tony L Administrator

    It’s very hard not to bring personal experience into things, especially given it is at its core a blog site. FWIW I share that viewpoint, I absolutely love the idea of direct drive, it is conceptually the best approach by far, but not even a brand new 1200G worried my 55 year old idler deck to my ears (other than the expected noise floor).
    tpetsch likes this.
  19. sonddek

    sonddek Trade: SUPATRAC

    Hmm. I'm going to have to do more listening, but I regard my 1210G, Garrard 301 and Well Tempered Amadeus as being pretty much on a par as drive systems. I can't really hear speed fluctuation on any. I use the same arms/cartridges on each, although my Amadeus has the theoretical advantage of an 11-inch arm. In terms of pitch/tunefulness, grip, slam, energy etc I would not be confident of being able to distinguish them blind. If I were to try, I would listen for the compelling bass drive of the Garrard, but I have no confidence that this is not just an idea in my mind. The other two decks also seem to have effortless drive, by different mechanisms. Probably the best chance of distinguishing them with a good pair of headphones would be to listen for motor hum (Amadeus), rumble (Garrard) and background silence (Technics), but it's down near the recorded levels of those noises on many records, so I think I would still struggle.
  20. Tony L

    Tony L Administrator

    For me it was a ‘flat earth’ musicality/tune-dem type difference. Nothing you could plot on a chart. The 124 was alive, organic and just swung/sang, the SL1200 cold, analytical and detached. Very much a ‘fun’ thing. To be honest I don’t even think it is a drive thing, I tend to find this with any high-mass heavily-damped component, e.g. I haven’t ever heard a heavy pair of MDF speakers I’ve really liked. They all just sound dead in the water to me, albeit in subtlety differing ways.

    Objectively the SL1200G is about as perfect as a record player can be, but I knew within two or three bars I’d be selling it on.
    tpetsch likes this.

Share This Page


  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice