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Most likely that particular speed with that particular momentum has just set the overcorrection in the servo into an oscillation where it's never happy. Remember: it's expecting a low mass, fast responding platter.Quote:
Originally Posted by Oldpinkman
That'll be low inertia, fast responding, I take it ;)Quote:
Originally Posted by MartinT
AFAIK all DC motors when used in a turntable will indeed need feedback to keep a steady speed. The motors used in cassette decks usually had this built into the motor itself and had a speed set pot accessible via a small hole in the back of the motor...
An AC synchronous motors speed is determined by the frequency of the AC that feeds it and can therefore be pretty constant even with load, whereas a DC motors speed is dependent on the voltage feeding it (and therefore the current it draws) and the load on it, which will vary with stylus drag, ambient temperature effecting viscosity of lubricants etc etc.
Hi Martin, So at what point with the techie is there a 'negative' effect. Are we talking from the moment there is even a slight increase in mass over the stock platter ?Quote:
Originally Posted by MartinT
Don't know, Robert. I can only report on what I've heard but I should think that there would be a gradually deleterious effect from the reference of a Technics platter/mat upwards in momentum. At what point you could hear the effect I cannot say.Quote:
Originally Posted by RobbieGong
Trans-Fi manage it with their Salvation TT though it took a lot of testing and development to make it work. It the end it was quite simple but everying had to be just right, including the 9kg platter.Quote:
Originally Posted by Arkless Electronics
Robbie, the compensation loop will be accurate within a given range of masses, one could probably safely assume +10% will make no difference. Beyond that i'd really be looking for some measured evidence or a serious piece of calculation based on a high degree of familiarity with the parts and the circuit values. Perhaps one of the designers of a heavy replacement mat can provide us with this information- surely they did the sums of took some measurements of speed stability with their new/old platters. Surely? ;-)
I didn't hear Andrew's deck sans step-up. It sounded very good with the step-up and based on the values I assume was still less than optimal with the 133ohms I had the Paradise loaded with. I suspect sub 50ohm is optional for that cartridge.
I don't think that Andrew choosing to remove the speed slider on his deck was the cause of the lack of 45rpm ability. From what I know of the 1210 electronics it just forms a voltage divider and I know two other people with technics who have removed the slider and neither of them struggle with 45rpm. perhaps someone else with an aftermarket platter and a strobe could chime in and clear this up. I don't know the internals of Andrew's deck so anything is 'possible'- but I figure unlikely.
As Arthur clearly mentions 'mass' per se is no measure or mark, but it's comfortable shorthand to use for discussing inertia, or more accurately moment of inertia, specifically an items ability to resists changes in its rotational speed and something that is defined by its mass, distribution thereof and rotational speed. I think we all know what we are talking about...
This debate has answered one question for me. I have considered pulling the trigger on a record puck for a while now as some partaking in this debate have argued that it is a better solution than a clamp. If high mass can cause speed instability on an SL12XX then I will be steering clear of pucks.
No Dave - a record weight/puck adds damn nearly nothing to the rotational momentum of the platter. My Stillpoints weight is heavy, but doesn't affect start-up or speed stability one jot.
The only thing to be careful of is not to use a very heavy weight with the standard Technics bearing as it may wear prematurely. If you upgrade to a Mike New bearing, you need not worry about any real-world record weight.
Why didn't I see that coming:doh:Quote:
Originally Posted by Oldpinkman
To my ears, it sounds crap (if that's what we're talking about, but if not, it's what concerns me the most anyway).Quote:
Originally Posted by Oldpinkman
I know that Martin uses a fairly hefty Stillpoints one, which he claims to good effect (and I trust his ears), but any of the high-mass weights I've used so far with the Techinics have imparted a similar (ponderous, 'dense') sonic signature, as I've described is imparted with a high-mass platter, and which I hugely dislike.
Consequently, unless Martin can demonstrate differently next time I'm down at his place, the Bruil weight which I currently use (340g) is the heaviest I am likely to go with such items :)
Marco.
The Stillpoints weighs 673g, so not in the super-heavy bracket. I love what it does, no ponderous sonic signature here.
I have the MN bearing and the MN copper-ally platter which is significantly heavier than the original platter (even with the 6mm thick original platter mat). There was never the slightest amount of warble, neither with 33,3 nor with 45 rpm. The MN bearing brought the biggest increase of SQ but also the heavy platter was a very worthwhile upgrade and brought a lot of "security" to the rhythm which was not as pronounced with the original platter + SDS isoplatmat + Herbie's mat 2 (a combination which was very good sounding!).Quote:
Originally Posted by WOStantonCS100
I had speed problems at 45 rpm with MN bearing and original platter but these were the dreadful "motor dynamics mod" from Dave Cawley. Removing the two components (a resistor and a capacitor) from the PCB restored the torque to it's former glory. Maybe all the mods to the electronics in Andy's (Rexton's) Techy did reduce torque like the "motor dynamics mod"?
Contrary to popular belief I think the flywheel-effect of a higher mass platter (like the MN copper-ally platter) is beneficial to the sound. At least that's what my ears tell me!
:sofa::sorry:
All the mods were done by Paul Hynes. The slider pitch and its components are still alive and well on my PCB. I have no idea why 45rpm is a tad slow. As stated in an earlier post I would optimise the deck further and remove all remnants of 45rpm from my deck, I simply dont use it. I have a Garrard 301 so if I need to play any 45's I'll use that (and the deck is no slouch either :eyebrows:).
I don't doubt that, Martin, but I'd need to hear it for myself on my own T/T :)Quote:
Originally Posted by MartinT
Marco.
Hi Andy,
The only things I did to the deck were to repair the damaged regulator modules after your soldering mishap and replace various on board power supply capacitors on your replacement motor board. I left all the other circuitry alone because, at the time, I had not verified any other mods myself on my own deck. I used my standard platter to test it and it was fine on test.
Aside from the platter issue there are other possibilities. The replacement motor board that you acquired was second hand. Perhaps there is a minor fault in the control circuitry on the replacement board that affects the 45 RPM speed control enough to prevent it reaching 45 RPM with a heavy platter. If this is so, it may have been there at purchase or it may have developed later on.
There would only be a couple of reasons why a motor board would be offered second hand. Either the original deck/arm itself had been thrashed to the point of being trashed mechanically and the motor board salvaged from it, or the motor board was malfunctioning and had been replaced, with the malfunctioning board being sold on.
If I think of anything further that might be helpful I will get back to you.
Regards
Paul
lol 37 pages,
OP had made a decision by post 6.:)
Paul I'm in no way slating your work, in fact my deck came back transformed when It came back home, again many thanks. I just wanted the other guys to get a grip on what mod work had been done to the main pcb (which you describe perfectly :) ). Dont worry about having to get back to me, I'm very very happy with the deck I own. You just keep thinking of ways to more out of the 1210. ;)Quote:
Originally Posted by Paul Hynes
True we have 37 pages but at least it details the current status of platter development and con-current problems which may arise from using said platters.
Hi Michael,Quote:
Originally Posted by krugdoktor
Your post beat me to it on the subject of feedback-loop mods.
Martin, when you talk of warble with a heavy platter, was this before or after you removed the "motor-dynamics-mod".
As I understand it from DC he "invented" this mod to make the SL1200 sound more like a SP12
If there are any of you who have this mod on you PCB then get rid of it.
Further when we talk about heavy platters, what weight are we talking about??
My Copper Bonded Platter weighs in at about 10Kg and as Mike says he has nothing but praise for it, and comimg from Vienna he must know!
Are there heavier platters in use?
Mike I have your bonded copper platter and I dont have the DC mod.
The motor dynamics mod made 45rpm virtually unlistenable with your platter Mike. I removed it a long time ago after DC told me that it was designed to reduce the torque of the motor. If anyone still has the mod installed, I suggest you remove it as you're not getting the full benefit of that glorious direct drive motor.Quote:
Originally Posted by Mike_New
The warble after removing the mod was very much reduced.
I don't believe so. I am told funk1 is 1.4kg, standard technics 1.8, funk 2 about 2.2kg. What does etp weigh? There seem to be some very conflicting subjective assessments here. Time for someone to stick a scope on it. This can be measured surely?Quote:
Originally Posted by Mike_New
Agreed. I think it's time for some objective testing.Quote:
Originally Posted by Oldpinkman
Let's also keep in mind that like motors were used in Technics changers/stackers where by quite possibly 6 12" vinyl records would be stacked on top of one another with the expectation that the motor would still spin all at the rated speed. My father still owns one and I can assure you, it does just that. At an average of 120g per LP, that's another 720 grams of weight spread out (not concentrated in the center) on top of the platter. So, in reference to record weights, a Techy should basically not even flinch with the use of a Stillpoints or any other similarly heavy weight, heavy record mat or outer ring stabilizer.
Here are some quotes straight from Technics for two models which essentially share the same quartz-phase-locked motor platform with heavier platters than the 1200.
SL-M3
"2.5 kg platter reaches rated speed (33-1/3 rpm) in just 0.9 sec. thanks to use of high torque direct-drive motor. The platter is driven by a powerful heteropole direct-drive motor having a very high start-up torque of 1.6 kg.cm That means the massive 2.5 kg platter reaches the 33-1/3 rpm rated speed in only 0.9 seconds. Another advantage of using the powerful motor is that variations in platter speed are zero for changes in the fixed load of up to 1 kg.cm (In other words, the correct platter speed would be maintained even if a tracking force of 200 grams were used.)
W&F .022% WRMS (JIS C5521)
SL-1500MK2
"The integral rotor platter motor delivers 1.3 lb - in (1.5 kg-cm) torque to virtually eliminate the speed fluctuations caused by tonearm or record cleaner drag. In fact, if you could fit 150 tonearms tracking at 2 grams each onto this turntable, it would still rotate at precisely the chosen speed."
W&F .025% WRMS (JIS C5521)
A lot of objective testing has already been carried out in the excellent thread over at PFM. I submitted my Technics with MN Bearing / Funk Platter / Achromat test recording for analysis and the results are shown here. If others with heavy platters could do the same thing, we'll be able to make comparisons. Simon (SQ) has a test record with the correct waveform.
I hope PFM don't mind my reproducing the result here (all rights duly noted). It's a very good result when compared with several other excellent turntables.
http://www.kilmory.demon.co.uk/pics/...10_2_polar.png
Martin,Quote:
Originally Posted by MartinT
Thanks for directing attention to that. I've read back into the PFM thread. The performance of your modded 1200 is scarily close to an SP-10MK2. I have to say that this does not surprise me from listening to and/or owning almost all the "MK2" variants for just about as long as I've been alive. And, of course, the specs between the plain jane MK2's and the SP-10 are not at all far apart (in terms of measurements and design philosophy).
Now, I'm even more curious to see the plot for a heavier platter (with the same or nearly the same other mods).
Martin,
What are the units on you polar graph plot? and what is the centre point?, or has the polar plot been mathematically corrected for any out-of-centre rotation of the test record?
The variations are probably due to the efects of the interaction between the 12 driver coils and the 16 poles of the isotropic radially magnetised ferite rotor.
Here is another test that I have devised, perhaps Paul Stewart might be interested in this one as well.
There is or was available a center weight fitted with a crystal controlled laser this is mounted onto your record/platter and swithed on for 33/45
The idea being that the laser projects a spot on a wall or white board which can be marked and observed for deviation longitudinally/radially.
Now if a setup is devised to record these pulses onto a digital camera focused onto a screen in total darkness then we should be able to see either a single spot or a line which will be proportional the total speed deviation over a given period of time say 10 minutes or more.
This should settle the issues once and for all time.
I did not buy one at the time the device was announced as it was a bit expensive about $600 if I recall.
Hi MikeQuote:
Originally Posted by Mike_New
You need to fully read the PFM thread. Essentially, a 3.15kHz test tone from a test record is played back and recorded digitally. This is then analysed and the data plotted polar-wise as shown, with the amplification greatly magnified to show any bearing or drive inconsistencies. A spectrum graph is also plotted to get an idea of motor cogging or other frequency modes affecting rotation.
Paul R is the chap who has the software to do the plots. It would be worth your joining PFM and having a chat with him directly.
The scaling doesn't mean anything in reality. Its an exaggerated scale for 5 revolutions of a 3150hz test tone recorded from a test record. Each revolution is overlaid onto of each other, the smaller the circular plots the slow the deck is running, it can highlight some very interesting things about your deck. In the PFM thread somewhere there is a standard 1210 plot and it was not good, the deck or test record could have been at fault. Simons plot for his modified Kuzma was excellent.
This is one of my SP-10s before and after I matched the drive transistors after I took out one drive phase :doh: Hint: The green plot is the good one! Its also scaled to show the difference.
http://i94.photobucket.com/albums/l8...lar_retake.png
Am I missing something? I confess to scanning through the earlier thread http://theartofsound.net/forum/showt...o-Towers/page2 but it appears Marco and others are trying a MUCH heavier and higher inertia platter, weight and a new bearing, and greatly prefering the sound to the standard technics, with no mention of the adverse affect on the motor causing "wibble". Marco talks of the strain on his Amex this vast improvement necessitates. Nobody has posted "even with the noticeable wibble caused by the heavier platters, we prefer the Oyaide / Mike New to the stock Techie". And these are platters approaching 10Kg
Now the Funk2 platter comes along, and the Mike New ETP sits in the wings, weighing 2.2Kg and it has a motor trashing effect that nobody troubled to mention before. Doesn't ring true. Of course - brilliant news for Funk if it is, since Funk 2 and ETP are too heavy to work, and everyone can buy Funk 1 instead. But doesn't ring true. I heard the "strata" platter against the standard technics, and, unprimed for a motor problem, heard none. I am down to Newhaven on Tuesday and will get a chance to hear strata against acrylic and will do so. Now - my only interest is whether to make Arthur do me a prototype strata for my PT - which is a considerable faff, since although there are no motor servo issues, the springs, sliders, and centre of mass are all affected. If Techie acrylic (which I haven't heard) is clearly better than Techie strata (which I have) I can save him the bother of the PT prototype. Unless the "problem" with the strata is motor wibble which wouldn't repeat on the Pink Triangle.
I hae me doots.
And Martin - what do your plots tell us about this platter mass/inertia issue? They don't measure any of the heavy platters. So we still need some measurements of the alleged phenomena. I am hoping Arthur will get his silly scope out, but anyway I will take my Nimbus records 45rpm Dvorak 9th down with me, and Little Jimmie Osmond "Tweedle de dee" which Sue has kindly agreed to lend me :cool:
Hi Neil,
So you are saying that the vector magnitude is the speed versus angular position in degrees; plotted as XY co-ordinates
I guess that makes sense.
"The sonic presentation of the SL-1210 now has a power and authority, together with a sense of ease and lack of strain that I've never before experienced. As good as the deck was previously, with it already being extensively modified and upgraded elsewhere, when the stock platter was in place (with any mat), there was a tendency for some material to become 'shouty' and for the overall presentation to lack a little subtlety - and with it the sense that music was being artificially processed, rather than delivered as a genuinely credible and real performance.
This rather annoying 'signature' had always been present no matter the effect of upgrading the PSU, tonearm, mat or feet - until now.
With the Mike New platter in place, gone is the somewhat 'clangy' and sometimes slightly 'over-insistent' presentation of the Techie, and with it the tendency for voices to sound 'shiny' and a little metallic. What one gets now is real depth, emotional expression and tonal colour, which when framed within the significant reduction in the T/Ts overall noisefloor, combines to create a palpable sense of realism.
Quite simply, with the Mike New platter in place, the Techie has finally 'grown up' and thrown off the shackles of its somewhat uncouth exuberance, and more than ever now, has become a genuine (and serious) hi-end turntable. It is now crystal clear to me just how much the flimsy and resonant 'bell-like' stock platter influences the sonic performance of the superb Technics motor unit, and how this effect manifests itself on music.
I feel that this is where the real sonic improvements of the Mike New platter lie (greater mechanical integrity and lower resonance), rather than anything necessarily to do with increased mass, as it fundamentally addresses the deficiencies in the design of the stock platter. Remove those, and the superb Quartz controlled D/D motor and control circuitry take the extra mass of the MN platter in their stride (from initial start-up onwards) and deliver a musical presentation with uncanny realism that engages and beguiles one in a way which almost defies belief. "
What's going on? :scratch:
In my case, the negative sonic aspects of the high-mass MN aluminium platter were only discovered when said platter was compared directly with the Funk one, firstly with my T/T at home, and then later in Martin's system, using both my T/T and his. Therefore, that discovery was made much later, after my initial impressions were posted about the improvements the MN platter produced over the stock Technics one, and were simply not mentioned on the forum until the matter came up again much later.Quote:
Originally Posted by Oldpinkman
I still fully stand by those comments, as even though the MN platter is by no means perfect (is anything?) it still offers a massive improvement over the stock Technics one (or indeed any combination of 'fancy mats', such as the Oyaide, used on the stock platter), which is a major contributory factor of the, shall we say, less than 'audiophile' sound quality produced by an un-modified SL-1200/1210 (as indeed you've succinctly described, ahem, 'elsewhere' ;))
Let me make this crystal clear:
Mike's composite aluminium platter still remains as a viable upgrade option over the stock Technics item, as it brings some unique sonic qualities to the table (no pun intended), with the Technics SL-1200/1210, that no other aftermarket platter I've heard gives, and in some systems (e.g, Rexton's), the benefits of that will outweigh any negatives, such as have been outlined here. It's simply that Martin and me overall prefer what the Funk (MK I) platter does, in the context of our T/Ts and systems, and believe it to be, overall, more compatible with the control circuitry of the Technics.
In any hi-fi system, synergy between all constituent components is what matters most - and so in some contexts, the 'high-mass' MN platter will be a more ideal choice than any other. The same applies with all the other platters. Therefore, much to the dismay of some (those too lazy to think or make decisions for themselves), platter-wise, there is no 'one size fits all' or universal 'best' - and so, as ever, one simply has to use one's own judgement criteria, and preferably listen to some of the options available, before deciding which solution (if any) is right for you :)
Marco.
Marco
I appreciate your points, and concur about our individual preferences and need to choose for ourselves. And I can fully understand how one product can be better than another, until a 3rd product comes along. But the issue here is not a subjective appreciation of the blend of sonic preferences which legitimately affect our choices. It's how much mass the Technics motor can work with. An objective technical issue, which could be measured, for which, for the minute, we are using the "ears as the final arbiter"
My interest is peripheral in a way, since almost regardless i hope to get Arthur to produce a strata PT platter just to try. But it will be helpful to hear the 2 materials on the Technics (since they are both available). The issue is does that decks ability to handle the mass of the platters enter the equation and invalidate the test in the context of choosing a material for my Pink Triangle?
And in that context, in the post I quoted, referring to a platter which I believe Mike New has stated weighs 10Kg, you stated "and the superb Quartz controlled D/D motor and control circuitry take the extra mass of the MN platter in their stride (from initial start-up onwards) and deliver a musical presentation with uncanny realism that engages and beguiles one in a way which almost defies belief. "
I don't understand how that comment fits with Martins assertion that he can "hear" that the motor can't cope with just over 2Kg.
That is my confusion :scratch:
Sorry, I can't help you there. The comments you've quoted from me on that thread, in reference to the abilities of the Technics D/D motor, were posted before I became aware of the negative aspects produced by the MN platter, which prolonged listening and further comparisons unfortunately revealed only too clearly.
This proves how dangerous it is to make snap judgements in audio, and why I resist arriving at a final conclusion about any piece of audio equipment, until after having spent sufficient time with it, in order to get a proper handle on what it's doing.
Being completely non-technical, I can't offer any valid opinion on the graphs or test results published from pfm, or on Martin's assertion above. I've posted here simply to clear up some of the confusion (which Biff outlined) in relation to my earlier comments about the MN composite aluminium platter and where I stand on that matter now :)
Marco.
In isolation, Richard, it tells you little except that the Technics has a great drive system with little signs of motor cogging, the MN Bearing doesn't have stiction and and the Funk/Achromat combo are an ideal weight. That's why I suggested that we need similar plots for some heavier combinations where we can start to make comparisons.Quote:
Originally Posted by Oldpinkman
Remember, though, that all the test plots are taken at 33rpm and the issues with heavy platters are more evident at 45rpm. Two of the reasons I didn't notice the issue for quite a while is that the problem is subtle at 33rpm and you need to know your system very well; and I rarely play 45rpm material.
If you remember, you were relatively unaware of the problem with the MN platter until I brought the Funk platter down to your place and demonstrated it to you... ;)
Marco.
But it's not, it's not really about the motor as such, it is more about the motor adjustment circuit and the feedback circuit. I realise that it may sound pedantic to make such a distinction but there is a tendency to make simplifications, and draw parallels, that are not valid.Quote:
Originally Posted by Oldpinkman
Perhaps I should add: the step-up in sound quality from the Technics platter to the Mike New heavy platter is very large. From the MN platter to the Funk platter is much smaller. Let's not get things out of proportion here.
Yes, exactly, which is why I posted my message above stressing that the comparison is more subtle. I was also more aware of it when playing 45rpm records, and once heard it was easier to spot.Quote:
Originally Posted by Marco
Precisely...
In fact, the effect is so "subtle" (I would refer more accurately to it as 'deceivingly unobtrusive', until exposed), that you were largely unaware of it until uncle Marco came down and demonstrated it, lol. That was a rather enlightening day, in various ways, if you remember! :)
Marco.
Absolutely. I appreciate the point. And that ability is related to inertia not mass. But the discussion had simplified itself down into "heavy platters cause the motor a problem which can be heard" and I was going with the flow :)Quote:
Originally Posted by YNWaN
yawn..lets move on now :)
As ever with anything 'hifi' if one chooses to strike out on a quest to upgrade, the journey will highlight subtle textural differences in the reproduction of music as one seeks to improve individual elements within a system. Often these differences are positive but occasionally they can also be negative. What cannot be denied is that any perceived improvement (or otherwise) in musical reproduction is intimate to the individual concerned and it is he or she who is the final arbiter. This is why there are such a diversity of products available as the various manufacturers and developers know this to be the case. The discerning audiophile will never tolerate a 'catch all' solution because their appreciation of music goes beyond the norm and on into subtleties of timbre. My apologies if this seems a little pompous, it is not meant to be.
If that's pompous, then bring on the Piat d'Or.Quote:
Originally Posted by synsei
:eek:
arthur
I wouldn't presume to comment about pompous. I will indulge in another hand-wringing bout of angst about the shift in the market away from dealers. Nothing wrong with the principle, except htf do you get to audition stuff? Before you pipe up Marco, why did a serious buyer and loyal forum member like Al end up buying a platter blind instead of having the chance to dem them? Who is going to lend me a Dynavector 20-2, Ortofon Cadenza Black and Blue, Shelter 5000, and one of Paul's tasty Reffc cartridges to evaluate. Ultimately i am seriously in the market for a good cartridge - but I don't rule out the possibility that my needle from Arizona will be the cartridge of choice. So what does the discerning audiophile do about that? :(Quote:
Originally Posted by synsei
No. You'd better not.Quote:
Originally Posted by Oldpinkman
I'm looking forward to a decent Penfolds (prefer a Rioja) next Tuesday.
OK. P. d'Or it is. Blue Nun? Either way, by the end a blunt G800 will sound just fine.
We'll get in trouble if we have too much of a private love-in on here, but I would note I know someone with a DV20-2 who won't lend it because its a virgin! About the only virgin I've ever known at your gaff mate! See you tuesday, and as I recall it was your round! :cool:Quote:
Originally Posted by FunkArt
No one dems cartridges as they are effectively 2nd hand then, they look at reviews, research the best product for their application, if lucky enough to find a good dealer who send things out "on trust" great, if not buy it and use the distance selling regulations to send it back if it's no good for you.Quote:
Originally Posted by Oldpinkman
Many websites sell boxes, the owners don't even have hi-fi systems at home, those with 100's of different brands who don't really care about what the customer wants or needs they just shift boxes, other sites with a small number of carefully chosen brands who care about what they sell and are obsessive about hi-fi and their customers, then there are all the ones in between the 2 I have highlighted.
I would guess Al ordered a platter because A. he can afford it B. he has read others have got one and like it C. he is an obsessive tinkerer who likes his toys (like a lof of us)
I'm interested to hear the results on a platter "bake off" as I have one listed on the upgrade path, even though it won't be realised for a while. There is the bearing and tonearm to be done first.....