SP10 Mk II vs Mk III

I have asked myself how the mat got warped in the first place, for a clue as to how to remove the warp. I assume it absorbed moisture, but I question my own hypothesis; why should rubber absorb moisture? Anyway, it's got to be totally flat to be useful as a platter mat, so whatever is done probably should be done with the thing under some sort of pressure to squeeze it flat. I guess brief boiling could not hurt it. It is NOS, was never used at all, came to me in original wrapping, complete with warp.

Lewm, What is the weight of the stock mat? Where did the info come re: servo and weight? I am still using the stock mat with my mkll and in the market for on now. Who did you purchase your Saec from and how much does it weigh?
thanks
Richard

Rich,
The stock mat for the Mk3 is ~540g. The SAEC SS300 is ~850g. I don't have a Mk2 mat handy.

Rich, I did not mean to lead you down the garden path. For what it's worth, I did find the MKII stock mat to sound just fine, even though I did like the SAEC a bit better. The 2A mat and the Denon DP80 mat are both thicker and more rigid than the MkII mat, and the Denon mat does color the sound compared to the SAEC. (I have more experience with the Denon.) Please don't feel you have to go out and buy a different mat from stock. As to the question about mats and servo mechanisms, there was a thread on DIYAudio where this was discussed in connection with building a new power supply and electronic control for a MkII. The servo is "tuned" to see a certain platter mass. If you increase the platter mass too much, there is a danger that the servo action will be overdamped. If you decrease the platter mass by too much, the servo will go a little nuts because it is getting inadequate feedback. The unknown for any particular system is how much mass is too much or too little. The Technics tables have powerful motors, so it is possible that they will be quite tolerant of heavier mats, esp the Mk3, but motor torque is not the only parameter that would govern the outcome. As far as I can tell, the SAEC mat (wt given above by T-bone) does no harm to the operation of the servo on my Mk2A. It sounds good on my Denon, too, but looking at the strobe on the Denon with the SAEC mat in place, I think I may be able to see a very slight wavering of the speed, back and forth. Can't hear a problem, however, and it may be just my imagination, it is that subtle. But some of the very heavy mats, such as many of those sold by TT Weights, would be a no-no for a direct-drive turntable, IMO. TT Weights would probably custom build you a mat for a dd, however, if you specified the mass in advance.

Interestingly, the Kenwood L07D has an optional platter ring, which increases the effective mass of the total platter assembly by quite a bit, and all the added mass is at the periphery where it has the greatest possible effect. To compensate for that, the L07D Power Supply has a switch which changes operation of its servo when the platter ring is being used. This kind of proves to me that the phenomenon is real, not just theoretical.

T_Bone and Lewm, Thanks for the info. Putting together the SP 10 has been a pleasant journey thanks to all the info folks like you make available. Thanks
Richard

Raul,

Can you describe how your 1" MDF armboard is 'attached' to your SP10?

Thanks

Raul,

Sorry to persist. however, I notice earlier in this thread that you argued for the importance of tonearm set up in evaluating ultimate performance of your tt and its plinth. Yet it seem to me that you have suggested that your new armboard is independent from your actual SP10.

If that is true, I cannot fathom how effective distance, overhang etc can be perfectly set with any stability. For anyone who was considering trying out your suggestion, this is surely a problem to which I have not seen you respond.

Apologies if I am missing something or you have already addressed this problem elsewhere. If anyone else is aware of how Raul could address that issue and he does not feel inclined (for whatever reason) to disclose this information, please feel free to suggest it here.

Cheers

i need help regarding recapping my mk3 power supply. symtom i experienced today was the turntable suddenly stop during track 2 and i have to press start again and it work fine... so what i did was i keep the turntable run for 2 hours and it did not stop . but this is the second time this happen and i dont want to ruin my cartridge if anything happen. can some one give me some pointer of how and where i can get the power supply recap or where can i order the electronics part i live in thailand

thx

Voraratc, I suggest you purchase Panasonic capacitors that are available from Digikey, on-line. If they won't ship to Thailand, then perhaps you can do a search in your area for a source of Panaonics. Nichicon and Silmic are superb choices, as well. You will need a wide variety of capacitors in different values and voltages. You may be able to find an SP10 Mk3 parts list or service manual on-line, as well, so you will know just what you need to order. Try Vinyl Engine for those documents.

regarding strobe noise. I once manufactured powerine filters and using general purpose filters, the first thing I did was disable the neons which through my ribbons added a clearly audible hash. It would be possible to snub the noise but why bother, just disable the neons.

slarty, That seems like a good idea. How did you do it? I imagine you could just disconnect them from their supply voltage.  Then the strobe goes dark, does it not?

MK3 strobe is LEDs.