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View Full Version : 11.5Kg high rotation flywheel, for a 20Kg platter, both magnetically levitated!



skaloumbakas
01-05-2004, 12:09 AM
Hi,

The following is an extreme design in my favourite analogue domain, which I thought I should share:

Please, visit: aca.gr/paper37.htm (http://aca.gr/paper37.htm), which is a paper (included in the http://aca.gr pages), mainly describing most of the technicalities of a huge flywheel design (turning at 375rpm for 33.33RPM) for a huge platter, both magnetically suspended (many pictures included).

I am also taking the chance to review my whole analogue set-up, raising and analysing many subjects of an analogue system as a whole.

So, I cover the following subjects:1. The current state of the analogue set-up. ('aas gabriel', Swiss hand made t/t)
2. The description of the t/t elements.
3. The flywheel project. (My extreme DIY intervention...)
4. The finished analogue system set-up & accessories.Listening comments and concluding notes will follow soon, after the break-in period...

Regardless of the extremism of the design, let me assure you that many of the included topics will sound familiar and clear up, (I hope), some of your queries you possibly have, regarding a good analogue set-up...

I wish you all a very Happy New Year 2004.

Maron Horonzakz
01-05-2004, 07:15 AM
OH WELL !!!!! Do you think it will sound as good as my NEUMANN masterdisc recording lathe AM 32b & WESTREX stereo cutting head 3A ???

skaloumbakas
01-05-2004, 07:22 AM
You got my point and I got yours...

Christos

Maron Horonzakz
01-05-2004, 08:09 AM
The magnetic suspension of platter Is a good way to minimize bearing rumble. Several other TT designers have gone down this path. Keeping platter distortion Noise & rumble below - 100db would be a goal to strive for. Can you do that? I have seen many claims but upon testing they fall short.

skaloumbakas
01-05-2004, 09:26 AM
No rumble at all (if the recording does not contain any rumble noise that is...)

Maron Horonzakz
01-05-2004, 09:46 AM
I dont believe you . All TT have a noise floor .

skaloumbakas
01-05-2004, 09:57 AM
No Sir, NO rumble at all...

Alex Lancaster
01-05-2004, 11:57 AM
Hi Christos:

I visit aca.gr every so often, and with a friend whose setup is in Your page, are building, very slowly unfortunately, a TT which I designed.

I cannot understand why so high inertia is needed, but to each his own.

Some points which maglev advocates do not seem to notice:

Since You have a more ideal "spring", with little hysteresis, when You apply a force, such as vibration, the platter will tend to vibrate forever.

If the platter and the arm are uncoupled, there will be vertical variations.

Regarding the oil, I will use "Omega 636", much less viscocity than SAE 1W, but with relatively high surface tension, about $30 USD a liter; WD40 is more of a solvent, and it evaporates.

When You join the ends of fishing line, string, etc. with a knot, donīt You get a bump when the knot passes thru the platter and capstan?, I would really like to know how You solve this, maybe iron them?

Thanks, Alex.

skaloumbakas
01-05-2004, 12:29 PM
Hi Alex,



I cannot understand why so high inertia is needed, but to each his own.That's what I though myself but listening to it after the flywheel was in place, it seems out of this world. Music becomes so frightenly LIVE you cannot imagine.



Since You have a more ideal "spring", with little histeresys, when You apply a force, such as vibration, the platter will tend to vibrate forever.I do not understand the question.



If the platter and the arm are uncoupled, there will be vertical variations.No they are not. Arm base is extremely heavy (and so is the sub-chassis...). With this design there is a decoupling of resonance believe me!



Regarding the oil, I will use "Omega 636", much less viscocity than SAE 1W, but with relatively high surface tension, about $30 USD a liter; WD40 is more of a solvent, and it evaporates.This is why I have abbandoned WD-40 as well (I mention it in the paper) for an extremely light oil (light almost as water...)



When You join the ends of fishing line, string, etc. with a knot, donīt You get a bump when the knot passes thru the platter and capstan?, I would really like to know how You solve this, maybe iron them?Simple knots are possibly heard with you ear above the motor spindle but they are not transmitted what so ever to the cartridge and to the speakers. There is great distance and high mass between motor and platter. Now with the intervention of the flywheel, I think we should not discuss it any more (although, as I mention, I have abandoned those threads but for other reasons)


Thanks for your remarks,

Maron Horonzakz
01-05-2004, 01:05 PM
How did you obtain the friction free shaft bearing?

Alex Lancaster
01-05-2004, 04:28 PM
Christos:

In other words, the platter is supported by a near-perfect spring, the magnets, when a vibration, from the speakers, or from the arm assy., magnetically and thru the spindle (there is a shear force even in gas), the platter will tend to keep on vibrating.

No matter how heavy and how well damped the arm base is, some vibration will affect it, and having a 15Kg. platter, it will take a little time to react. so there will be a vertical movement between the arm and the platter; All this, of course, if You believe in one I. Newton.

Alex.

skaloumbakas
01-06-2004, 12:16 AM
Alex,

The platter is 20Kg and when I put my finger on its spindle to vibrate it, the frequency is 2 - 3 Hz (BTW, 4 -5 Hz is the frequency I can vibrate the 11.6Kg flywheel).

This is the only way I can move the platter within a vertical plane: WITH MY FINGER ON THE PLATTER WHEN TURNING.

As you understand these low frequencies do not exist in a listening room when you play music but even if they do, they are so low energy, it is impossible to move the platter.

I am very surpriSed from the question - have you seen this happening in any other magnetically suspended heavy platter - Verdier maybe?????

As for the heavy arm base (I think it is 25Kg) NO there is no lateral vibration what so ever and all high quality turntables are built this way (Symhponic Line, V.Y.G.E.R. Bogdan etc).

If you tell me you don't believe me, the only way to believe is compare an aas gabriel t/t with anything else (analogue or digital...)

I have compared many analogue vs. digital gear combinations (during Club meetings - not cheap gear that is...) and the greatest difference in favor of the analogue I have found is with my turntable... And that before the flywheel entered the game - now the difference is simply astonishing with my Wadia 8/15 (improved) combination...

Cheers

skaloumbakas
06-26-2005, 02:11 PM
There have been updates to this paper and it is now finished (at last...)

If you have time, please re-visit:
http://aca.gr/paper37.htm
(Heavy weight-high rotation magnetically suspended flywheel for a large mass magnetically suspended t/t platter!)

Sorry for the 20 months delay...

Maron Horonzakz
06-28-2005, 07:34 AM
Maybe a 10mm wide polyurethane belt with inside surface dull textured to minimize slippage. With that width it would be simpler to maintain. Of course a new drive spindle would have to be made. But traction of belt would be increased. I would recommend trying this. It should,nt be hard to machine a new drive spindle for this test. Im shure the company supplying polyurethane belts could be persuaded to make wider belts. .....Maron

skaloumbakas
06-28-2005, 08:32 AM
Thanks very much for your feedback Maron.

Surely they make flat belts, as wide as you like, and probably you are right (I supose you are talking about substituting the 5 round belts, with a wider flat one...)

I just worked out the contact area of 5 x 2mm round belts and the contact area is more than that of a 10mm flat belt. (Comes out to be 16mm...)
So maybe a 16mm belt would've been another solution, but... I do not have the courage for further experimentation...

I have no slippage at all, as I am now anyway...