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The bunfight below regarding the pains attendant upon the vinyl ritual prompts me to ask this:Is there a place in the ritual for a device which allows removing the effect of off-centre pressings? If so what would you expect to pay - would $1000 on top of the price of the TT be too much?
It occurred to me that computing power which would have been a designer's wet dream in the 80s is sitting next to each of us. With the right peripherals a "computing platter" as per the Nakamichi Dragon is achievable as a plug in to a laptop. It would cost a bit more to make it stand alone.
At this stage the device is vapourware but the vapour has two parts - a modified platter which allows the record to be re-centred and a separate device which measures the adjustment required. Each side would only need to be measured once and the appropriate data recorded (!) so that the adjustment could be replicated. In theory the reduction in eccentricity would be better than 99%, eg a 2mm offset (enough to cause 1% RMS speed wobble) would be reduced to better than 0.02mm (less than 100ppm)
Jose K, I'm going to need your help handling the serial data stream.
Follow Ups:
Just thinking off the top of my head here... What if you used an eccentric spindle, some type of accurate laser measuring device for the side movement of the headshell and your computer for calculating the actual center of the pressing. Line up the top of the label to 12 o'clock on the platter (marked), put the needle down, measure the headshell movement, computer spits out (for example) 4 for 4 o'clock, line label top up at 4 o'clock (being sure to press record toward indicated direction), put clamp on and play record.This would be repeatable so it would only need to be done once and you could mark the X o'clock on the sleeve. Don't know how accurate it would be but it would surely beat the pants off of how I do it now. Once the measurements are done you could remove the laser device so there'd be no changing the looks of the table.
the edge of the records center label, and based its computing on aligning that ( ie, no run-out on the arm, meaning centered )
No laser
Close to what I'm doing, mine uses a slightly different trick to make it simpler.
Any workable solution for off-center records would be great, I have many of those, and I do hear the effects, and who wants to gouge out the spindle holes? Not me, although I've done it.
But I do recall an aftermarket accessory back in da eighties which allowed for single LP off center detection. And then modification to the LP for concentric rotation. And .... (it gets better), don't remember exactly what the "kit" included. But, I do remember something in the marketplace.Of course there is the rather folkloric ritual proposed waaay back by an industry uber-tweak/guru/designer/manu(?). Of finding the 'right' orientation of any/each record, marking/noting same. And always playing thus. Glanced it in an old post I happened on the other day, must have seemed quite strange back then (didn't save the link).
No, don't mention it (glad to be of help).
Center-A-Disc?I was looking around for that type of thing and saw it mentioned. Don't know what it looks like, or how it goes about centering a disc.
Ooops .... looks like they're still out to lunch. Well we'll await they're return. In the meantime, around here, it is now officially Miller Time (court will remain in recess).
:-)
was it the "Soundtracktor" or am I thinking of something else?
Owned one in the eighties. Sold it. That spike for arm yoke/centerpost location kinda gave me the willies.So, sorry, our prize jackpot will now rollover til tomorrow, when some lucky contestant will have another chance :-)
and patches the edges of the old one. Might be a little easier than a dynamic solution.
As has been pointed out before, that only works of both sides have the same offset. Not likely.Besides, shifting the centre of rotation is the easy bit. Calculating where it should really be is the tricky half. This is why I don't think the Roksan solution is much of a solution.
vinyl nirvana?Vinyl by it's very nature is a sort of miraculous result arrived at from a hoard of imperfections, *perfect* centering does absolutely nothing to dispell the vast majority.
An interesting intellectual exercise perhaps but pratically speaking it seems no great surprise that the history of vinyl reproduction has seen so few "Nak"s.
That is true, and there are a couple of reasons for that. First, Naks were prohibitively expensive. A Dragon CT in the early to mid 80's cost about $2K, whixh was a lot of money then. Second, not many were made because of timing. The digital age was coming and analog was dying. Actually, the history of vinyl reproduction has seen very few truly state-of-the art machines. And those who own Naks usually tend hold on to them, and that is another reason you see so few of them sold.
I've been playing with theoretical models of turntable performance for a couple of months now looking at how different approaches interact with one another. I am in the process of building a prototype of a new table that incorporates the ideas that came out of this, so we'll see how well theory and practice agree shortly.As you are probably aware speed stability has been an interest of mine for a while. Every time I achieve better speed stability I like the results, so I think it's worth pursuing until I stop being able to hear the difference.
The remaining unsolved aspects are lathe performance and disc centring. Nothing I can do about the lathe, something I can do about centring. Making a re-centrable platter with micron level positioning accuracy is surprisingly easy and cheap to do. Measuring where it needs to be is tricky.
There is another audio reproduction format available today that exhibits perfect speed stability, no wow & flutter whatsoever, ruler flat frequency response, linear phase response and virtually unmeasurable distortion. It's really cheap compared to what you want to do with vinyl reproduction. Perhaps you might want to investigate it for more than simply reducing eccentricity.Just a thought!
"Perfect sound forever" anyone?
Ah, no I didn't know that, best of luck.On the current topic are there not issues such as the concern with structural rigidity with a moving platter (which presumably will feature motion along at least two perpendicular axis) vs. what is possible with a fixed (platter) solution, i.e. the normally encountered enginnering trade-offs?
I imagine as well that you are aiming for superlative accuracy in many areas, not just speed stability and record centering, so I was wondering if (to mention just one additional concern) tangential tracking is out? Of course linear tracking is said to have it's own set of challenges... seems there few magic pills in LP reproduction.
No Guru, No Method, No Teacher
As I said, the solution is amazingly easy and cheap once you twig to it. Involves no compromises that I can see. No platter movement except rotation.Regarding tonearms, I have a couple of ideas there too. As far as I can see linear has more compromises than pivoted. What I don't like is any of the pivot methods used so far, so I'm going to change that. I showed my prototype of the bearing structure to a friend (who teaches science) and he said "only you would have thought of that". I'm not sure if that's a compliment.
trying to be the new Takeshi Teragaki?And that's a compliment...
Do you envisage updating your website with your findings, or has it
all become confidential now that you're building a complete turntable?
I think he is trying to duplicate the accuracy of digital while still being able to call it vinyl. If he wants to attack a significant problem with pivots, he should figure out how to localize and stabilize the pivot-point of the cantilever in a phono cartridge. That is the most undefined and wavering pivot point in the vinyl process.
Sorry, I'm not trying to be cagey but a couple of the things I'm pursuing look to be patentable so I won't publish until I have done a search and maybe lodged a patent application.The design as a whole doesn't make sense unless that information is included, so there will be a wait before full disclosure occurs.
.
No Guru, No Method, No Teacher
over 20 years. If concerned about an off center record (I never have, never caused me any problem) just pull off the spindle cap and center manually (easy to do).Personally I leave the spindle cap in place... they have a way of walking away when removed!
No Guru, No Method, No Teacher
I've said this before, but, I Have never bought an alubum with a off center spindle hole. I do have a few with off center labels though.
Larry
Hey Mark,
I haven't heard back from you.
Did the package arrive in good order?
Me, I'm just a lawnmower, you can tell me by the way I walk....
-Ray
I won't get home until the end of the week but my wife said "There's an enormous and really heavy box here for you" on Wednesday. Thanks for everything, I'm looking forward to getting this set up.
OK cool.
I was worried that there was a problem since I never heard back!
Me, I'm just a lawnmower, you can tell me by the way I walk....
-Ray
I'm home, it's here and it's BIG.Everything seems to work very well - it's within its stated 1ppm spec without the required warmup period, presumably it will improve with warmup. In any case it's rather nice to be able to dial in 60.0000 Hz and get it.
I hadn't connected the OCXO to the reference input. It's now connected and the 3326A is accurate to the limit of my 8 digit frequency counter.
It would probably be easier and cheaper to get a used Nakamichi Dragon - about $2K...
The trouble with the Nak is that they are virtually impossible to fix if something goes wrong, and something will go wrong with 20 year old electronic components of that complexity.
Yes but how much would it cost to replace the few LP's in a collection with this off center hole? Granted if your talking about some uber rare Jazz recording then it could get quite expensive to replace. But then do you really play that uber rare Jazz recording?I collect and play Classic rock and I can't think of an LP that I could justify spending that much for a special TT that would shift it's spindle center so I could play it. Since if the devise plugged and fixed the bad hole it would also ruin the value of the Uber rare LP.
The cosmetic parts are not available, but you can get a Nak fixed. Jeff Galin of US Servie Labs still services them. The worst case scenario is you can get a parts unit. That being said, they are remarkably reliable. Mine was manufactured in 1982 and it still works like new. I am sure that it will outlive me. All of the Dragons I have seen that are not working have been mishandled or damaged during shipping. A friend of mine who is an engineer said that a Dragon CT motor could work continuously for at least a couple of hundred years, with the potential problem being not the motor itself but the switches that turn it on and off when you move the tonearm eventually wearing out.
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