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Linn LP12s – Fire away!

Discussion in 'audio' started by NickofWimbledon, Aug 24, 2022.

  1. sonddek

    sonddek Trade: SUPATRAC

    I don't claim to be an engineer, but it doesn't take an engineer to see that when a stretchy belt like the Sondek's pulls at a weight like the platter which is supported by three springs which happily rock sideways, energy is going to be delivered into the elastic parts of this highly resonant elastic system rather than its ideal destination: precise platter rotation. It may work, just about, for listeners who don't expect very accurate pitch from an expensive deck, but why all the upgrades? At the root of the current top-spec Sondek is a design flaw which has always been there and has never been addressed, except by people like John R, Arthur K and the erstwhile purveyor of the Spoke. The low uptake of those upgrades and the continuing popularity of the Sondek is what suggests to me that speed instability may be the key selling point. Maybe it sounds good because of a design flaw.

    The Xerxes is an interesting correlate. My memory is that the motor is mounted in a sprung rotating spindle, the function of which would seem to be to mimic the ineffective delivery of accelerating energy to a slowing platter which afflicts/improves the Sondek. Both decks are designed with elastic substructures in the linkage between motor and platter so that it is impossible for them to react in good time to decelerating forces, and consequently they will hunt for the correct speed in the way that PLL direct drives were falsely accused of. The difference between this flaw in the Sondek and in the Xerxes is that in the Sondek it appears to be an accidental side effect of an inherited and somewhat crude scheme to isolate the arm from motor noise, whereas the Xerxes scheme to mimic the technically undesirable behaviour looks like it was put there specifically to have this negative effect on delivering KE to the platter on time - in other words it looks designed to mimic a popular fault in a popular deck with less fuss.

    Of course, it will be argued that both schemes are there to compensate for the buzz of cheap motors, and the Xerxes scheme copies the suspended motor in Garrards and others, but note that the Garrard motor suspension isn't a spindle oriented specifically to absorb only rotation.

    All decks have flaws - I hope I will not be attacked or sneered at for discussing the flaws in offerings from one brand or another.
    NickofWimbledon likes this.
  2. per-Sony-fied

    per-Sony-fied Me in another jacket

    Well, today's research popped up an interesting read of a rather good review on Wigwam. Not without faults but the cumulative parts of its sound signature make for one very enjoyable phono stage. Have you tried it on the balanced output?
  3. Beobloke

    Beobloke pfm Member

    Interesting you mentioned the Spoke, as it was reviewed by Hi-Fi World when I worked there. As standard, LP12s generally turned in highly respectable W&F figures (in fact, the LP12SE recorded some of the best we measured for belt drive turntables), but the addition of the Spokes completely ruined this - both W&F and speed stability were all over the place!

    As was the sound quality, to be honest...
  4. AnilS

    AnilS pfm Member

    @linnfomaniac83 Simon now has my new old LP12. Thank you Simon for working some magic on it. ;)

    I'm reading this thread with interest and wondering what I've let myself in for :p

    Simon's fitting some fresh parts but having heard it unfettled, it sounds very nice.
    I did compare it to 5 turntables I have (I know :rolleyes:), but the LP12 sounded the best, given the extreme advantage of a new cartridge.

    Looking forward to the adventure but I'm hoping not to add any further enhancements, unless some has a clear lid spare. :D

    Only minor gripe is it's only 45rpm but I only have 3 12" singles o_O
    NickofWimbledon and Mr Pig like this.
  5. Chris

    Chris pfm Member

    Can anyone point me to JohnR’s elastomer insole thingies, please ? I figure that if my blue belt is better than any Linn belts I have tried, then why not ? I don’t hear a problem with piano note waver especially but what if other things improve ? plus I have a very solid floor ( and skull ).
  6. per-Sony-fied

    per-Sony-fied Me in another jacket

  7. david ellwood

    david ellwood Kirabosi Kognoscente

    If youve had your deck set up by a competent technician fitting bobbins could potentially undo a lot of hard work.

    If you havent had your deck set up by someone competent, why not?
  8. sonddek

    sonddek Trade: SUPATRAC

    I never heard one.

    I'm interested in how you used to measure wow and flutter. Earlier in this thread there was an interesting suggestion that the platter speed remains quite constant on Sondeks but the sub-chassis-arm moves around with the flow of signal strength. The famous Technics wow figure of 0.025% corresponds to a rotation of about a fifth of a millimetre at track one. I've seen it said that human threshold for audible wow is about ten times that, but I'm sure it varies from person to person.

    If you use some sort of test tone on vinyl to measure w+f, does that test how the sub-chassis would respond to repeating periodic impulses such as a musical signal? It seems to me that despite the consensus that test tones are adequate, a thorough test of sub-chassis reaction might be aided by an interferometer.
    John R and Mr Pig like this.
  9. Paul R

    Paul R pfm Member

    ISTM, as you're advancing your theories of subchassis motion, you ought to attempt to measure it.

    I've been experimenting with an encoder disc read from a pickup mounted to the arm board. But I only get 500 intervals per revolution and haven't got useful data yet. Other than a precise measure of average speed. More interesting perhaps might be to fit a DC motor and look at the current draw. You can easily see stylus drag, and how it varies across the side. Don't know yet if it shows signal level variations. If it does then this is evidence that the arm is applying a varying force to the subchassis and perhaps it's wobbling. But a lot is built on handwaving.

    FWIW Technics direct drives wow under load by design. It's just not very much. If you apply a load and watch the strobe you will see the markings move with respect to the reference. When you remove the load it comes back. The average speed doesn't drop in relation to the load, as it would with an open loop DC motor. But obviously the effect is trivial with a stylus level of load.
    Mr Pig likes this.
  10. sonddek

    sonddek Trade: SUPATRAC

    Yes, if you very gently use your fingers to decelerate a Technics and a Sondek they feel very different. The Technics seems to fight back instantly with significant torque whereas the Sondek creeks and totters and seems to struggle to get back up to pace. I'm not saying this has significance within the band of small forces due to stylus drag, but it's not impossible that it gives an insight into any difference in the sounds of the decks, if there is one.
  11. david ellwood

    david ellwood Kirabosi Kognoscente

    It’s not impossible but it’s very unlikely.

    I find putting a record onto the platter and playing it a much more reliable metric.

    But you’re welcome to stick to the finger method..
  12. Mr Pig

    Mr Pig Trade: ^'- -'^

    The Cirkus doesn't sound as soulless with it. It cleans the sound up but without killing the life. I have another deck with a pre-Cirkus bearing and sub-chassis but the Cirkus with the Stack sub-chassis is better in every way. I kinda hoped it wouldn't be! ;0) This isn't what gives you the recording tolerance though, that's the Rega arm.

    Incidentally, the Stack Tenor sub-chassis is compatible with the pre-Cirkus bearing. Not many alloy sub-chassis are. It's also cheap! And you can use a standard Linn armboard with it, that's what I've got.

    I've found that a 2mm shim works out about right for a Rega arm on an LP12. It's bang on for an Audio Technica cart and close enough for everything else. I wouldn't use an adjustable doffer as I think rigidity of the arm and good cable dressing are more important.

    For the life of me I can't see why the Audiomods arm would be better than a top Rega. I imagine that most of the people who buy one are going from a cheaper Rega arm or another brand. Removing the paint from the arm tube gives an increase in clarity and openness so it has that advantage straight away, but so does an RB3000. And do we really think it will have better bearings than Rega can do? They've been developing this arm for forty years. So why would it be better? I just don't get it. And nailing a cheap micrometer to it, really? You compromise rigidity for what, so it looks trick? Na, not for me. Bet Rega think it's pretty funny too.
    LPTvinyl, Colin131 and Miss Ariel like this.
  13. Chris

    Chris pfm Member

    Living where I do, the only person who has so much as touched my Linn is yours truly and I reckon set-up is mostly BS but if as Peter Cymbiosis says, he starts a set-up with about 15 springs to choose from plus all the different models of P-clips, screws and odds and sods, well, fair enough. What I can´t get on with after all these years is pulling downwards, not on the springs but on the grommets to liberate then from possible stress, which, en passant, I believe to be extremely important because they do move with time independently of the springs, and I often have to leave them as are because I just have no grip in my fingertips. So at my age I´m going to give the insoles a try. They sound right up my street even though I am unaware of any real problems with my set-up of what is, by today´s rates, a pretty low end level LP12.
  14. Denis McKeown

    Denis McKeown Active Member

    If Fender brought out - well they probably have - the 25th iteration of the Telecaster - I'd still probably prefer the 1952 original. I liked the original LP12 very much, and do rather miss it. Like someone else on this discussion I ended up with an SME 20/3/V about 15 years ago and it hasn't needed a single service or anything since. If I was buying a Linn now I'd get the most basic brand new LP12 and fit an old Ittok or Naim Aro.
    Ben&Ted and Mr Pig like this.
  15. Chris

    Chris pfm Member

  16. sonddek

    sonddek Trade: SUPATRAC

    I've never tried the balanced outputs. My volume control has RCAs, and my crossovers only take RCA inputs so not much point I suspect.
  17. Colin131

    Colin131 pfm Member

    Sorry for the delay to reply was busy the past few days.
    Yes it’s a shame the Ittok can’t be serviced. Never ever had a problem with one though and I’ve had many examples.. With the Ekos mk1 the only trouble I had was the anti skate being too stiff.
    Agreed on the Ittok bass. I’d probably miss it a bit too much if I permanently switched to any other arm.

    It’s weird but I find the Ittok to be good on brighter and thin recordings. The Ekos maybe less good. The Ittok is a bit warmer and less forward and that helps. The issue I was talking about with different records form different era I thought was more down to the LP12 type itself. For thinner and harsher 70s and 80s recordings I find a Pre cirkus deck worked well, and for modern recordings that are fuller and not harsh a cirkus or later deck is better, as they can be too bloated and slow with a pre circus deck.
    I’ve not really found that issue to be down to the arm, but I’d like to try the Rega or thé Roksan Tabriz one day.

    Can you give me a few examples of compressed music on records? If so have a look and see if I have some of them and see how they sound with the Ittok. No worries if you can’t think of anything off the top of your head though.
  18. Colin131

    Colin131 pfm Member

    The Audiomods arm did look quite bling with all the holes! I didn't think the sound was all that special but it was ok. Nothing bad.

    That tenor subchassis is cheap. Thanks for the info. That’s defo worth a go then, as it can take the old armboard too. Did you try it with a pre cirkus bearing too or only cirkus?

    I see re the shims. Thanks for the info. So I assume you set that height then just use VTA adjustments to dial in the SRA?
  19. Beobloke

    Beobloke pfm Member

    Wow and flutter was measured by the time-honoured method of playing a 3150Hz test tone on a carefully centred copy of a test LP and analysing the result using a W&F meter or audio analyser. It's not perfect, I grant you, but it's been an industry standard for a long time.

    There was some work done on dynamic W&F performance and recovery after an external stimulus back in the late 1970s. As I recall, Hi-Fi Choice in its A5 days used to set up the above test and then drop a 'dust bug' cleaning arm onto the record to observe how the platter speed was affected and how quickly it recovered. The results made interesting reading but it was then realised that this was in no way representative of a music signal or the type of resistance offered by a stylus in a groove, so it was pretty pointless. Certainly it quietly faded away not long afterwards.

    Reading this sort of thing now, and the results it often gave, it seems to me that its main advantage was that it allowed the mags of the time to take the piss out of cheap direct drives and, in those days of "the holy LP12 is the one and only" that seemed to be the most important thing.
  20. sonddek

    sonddek Trade: SUPATRAC

    Not a bad method would be a seven inch or ten inch disc with a test tone on top of a music LP and a separate arm on a pod. Play track one with one arm and the test tone with the other. Those who say that stylus drag suddenly matters will have changed their tune. I suspect that all sorts of decks with equivalent specs would produce quite different results.

    But an interferometer trained on the arm base of a suspended deck would be illuminating.

    Does anybody have a small mirror and one of those laser key-rings?

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