Technics SP10 MK3 Restoration


Just got my SP10 MK3 base (motor unit & controller) back from JP at FidelisAnalog.com
JP is one of the most knowledgeable on the SP10 MK3 and is the one who designed and manufactures the MN6042 Speed Control chip that keeps these and other Technics turntable models still operating.

My SP10 MK3 came with the stock Technics SH-10B5 faux obsidian base.
It has very low hours of use , no signs of wear at all on the bearing and not a single blemish, other than some specs of dust and a couple spots on the copper part of the platter that need cleaning.
but I would like to have a 2 arm, constrained layer plinth built and have the motor unit mounted 'naked'. I am presently searching somewhat 'affordable' plinth builders and suggestions would be greatly appreciated.

The work that JP did to both the motor unit and the controller:

1.       Pre-refurbishment measurement to baseline the performance of the unit and to see if there are any underlying issues.
2. Cleaning of all PCBs to remove the factory conformal coating. At~40 years this coating tends to become hygroscopic which can cause stability issues.
3. Physical inspection of all solder joints under an inspection microscope. Many of the joints will exhibit annular deformities which can lead to joint fractures down the road. These must be cleared of the factory solder and re-soldered. There will also be poor joints that need the same treatment. You can’t just reflow as the solder alloys aren’t the same which can also cause joint failure down the road.
4. Electrolytic cap replacement and rectifier diode replacement.
5. Disassembly and cleaning of the motor. Bearing inspection and service work. Proper Anderol 465 oil is used for reassembly. Motor is then checked for any areas of bearing drag.
6. The brake solenoids typically needs cleaned, and band tension is adjusted.
7. Stop/start and speed selection switches in the motor chassis are measured for contact resistance. Too high of resistance is indicative of a switch failure in the future. In the control unit I typically replace all the tactile switches, and the start/stop switch if needed.
8. Relocation of the brake regulator transistor to the heatsink to prevent overheating of the board (factory design flaw).
9. MN6042 replacement installation.
10. PSU ripple check at all critical stages (10).
11.   Course calibration is performed and post-refurb baseline measurements for FG spectrum, motor drive phases, etc. are taken.

12.   After 48-hour run-in final calibrations and verification measurements are performed.

The basic service returns the unit to factory or better specifications (assuming no permanent bearing damage has occurred).   This service is quite exhaustive and very different from the typical work I see of just swapping some caps out, checking some voltages, and adjusting phase tracking.

The advanced service adds on top of the basic service:

1.       Replace all polyester capacitors.
2. Replace drive circuit metal oxide resistors.
3. Replace all voltage regulator ICs and update circuits.
4. Replacement of certain diodes.

Rick


128x128Ag insider logo xs@2xrich121
No its not. the Artisan Fidelity plinth is a sophisticated constrained layer plinth using panzerholz and other materials and includes a drain block for the main bearing.

As always you have nothing to add @dover, and you always arguing about something that everyone know without your remarks. Links posted in all my replies in this thread.

When I said "just the box" I mean the design (the way it look), construction layers pictured in the article I posted earlier in this thread and everyone can see different layers.

No doubt the $10k plinth should work effectively, but it must look good too for this price at least. That was the argument and I explained why.

If you like boxes like this then I doubt you have a good taste. This is another bad example with those ugly baths around the tonearms and the drive pushed down into the plinth. OMA solution is so much better with the armboards on the corners. Their Garrard plinth is so much better (in terms of design) because they do not try to push the Garrard down into the plinth and do not make those bath around the tonearm, you know what I mean? OMA did the same with Garrard plinth and Technics plinth. The argument for a perfect look is to leave the Technics drive on top of the plinth (not trying to push it down) with the arm fixed on the same level (on top of the plinth).They did it, but ONLY after the metal chassis around the platter was completely removed, this is perfect. And OMA designed similar plinth for Technics.

I am not gonna discuss the "sound of the plinth" or the "sound of the drive" with anyone on this forum, this is the most boring discussion. I am happy to discuss design, because some of the most expensive high-end products on the market is almost always the ugliest in terms of design.

its a weetbix sandwich that uses magnetic steel plates, wrapped in thin alumium foil.


The "aluminum plinth" on Luxman PD-444 is not thin and not foil (!), the thickness of aluminum all over the cabinet around the sandwich is nearly 5mm, to see it you have to remove the sideboards, but nearly the same thickness of aluminum used for LUX amps and you can look at this "aluminum foil" (as you call it). The aluminum plinth is not supposed to be a whole piece of aluminum to weight a ton that impossible to ship. However, the Luxman chassis is metal and "armboards" are metal, and slide for armboard is metal, anyway this is not the subject of this post! The OP asked what I use and this is the only reason I mentioned Luxman, because I SOLD TECHNICS more than 3 years ago! You don’t own Luxman turntable and you don’t like Technics or any direct drive, so why you are in this thread ?


No - the plinth in the picture is a slate plinth, not graphite.

Did you ever check the links I posted to OMA site where you can read SLATE PLINTH!? So what you’re arguing about? Everyone can read it’s a slate plinth. BUT "Graphite" (look on this plinth) in my terminology is the color, same as OMA Graphite Mat and Graphite headshell. (it’s not just grey as you can see).

From my conversation with Jonathan (OMA) gerarding "graphite plinth":

"Double layer slate plinths are $3500, custom designed for whatever arm(s) you want to use. Single layer are $2750. Two arm plinths add $750 to either version."

The plinth construction and materials used can materially affect the overall sound of a turntable motor.


If you like ugly looking overprised plinths you can discuss their "perfect sound" with your audiophile friends.

I would rather go to buy more records to spin on my pair of Luxman PD-444 without thinking I have to change the plinth.

Regarding a plinth for SP-10 series I believe a custom made $300 baltic birch plywood plinth is enought. I want to admit that stock plinth for Denon DP-80 or Victor TT-101 are more than enought too, they goes for $300 and can be restored (waxed or veneered) by any pro carpenter.

I do understand that you might struggle to hear any difference with your knackered old 80’s MM’s that you think are state of the art.

I do understand that at your age you might not hear what I hear at all. This is far more important problem than a choice of cartridges. In fact one of my turntable with FR-66fx and FR64s tonearms are for LOMC only.

As a typical retired ex high-end dealer you can continue to brainwash your non existing customers in your dreams that to hear something good they must spend $10k for a plinth and another $10k for a LOMC cartridge. I’ve heard it before. And you are absolutely right that I refused to buy even $2000 plinth for my ex Technics, instead I bought two different PD-444 turntables with built-in plinth and I’m happy. My teak plinth was quite nice to hear everything I want to hear from my analog rig and genuine obsidian plinth wasn’t any better. Technics can be used without plinth on AT616.

You can continue to post your absurd about vintage MM cartridges, but I’ll tell you that when SP-10mkII was in my system my cartridge was this ZYX Premium 4D SB2 (it’s $5k modern LOMC) and Airy 3 with silver coil (another $3k LOMC). At the same time in MM arsenal these two beauties with EPA-100. Am I missed something?


I would not waste much money for such a box, whatever material. Why not using a vibration platform with it, Herzan or similar. Makes more sense
@chakster 
If you like boxes like this then I doubt you have a good taste.
If you read my post correctly above, I have already said that I dont like panzerholz, timber, plywood etc because it is not dimensionally stable.
If you like boxes like this then I doubt you have a good taste. 
As Salvador Dali said - "It is good taste, and good taste alone, that possesses the power to sterilize and is always the first handicap to any creative functioning"
 If you actually read my post above I make my own plinths using either ebonised bamboo or engineered stone - nothing like the Woodsong/Artisan Fidelity plinths. 

You can continue to post your absurd about vintage MM cartridges, but I’ll tell you that when SP-10mkII was in my system my cartridge was this ZYX Premium 4D SB2 (it’s $5k modern LOMC) and Airy 3 with silver coil (another $3k LOMC). At the same time in MM arsenal these two beauties with EPA-100. Am I missed something? 
Yes, a decent turntable.

Was out for the weekend.

Everyone, thanks for all the informative posts... so much to read here, again thank you!
@lewm
I very much appreciate your offer. 
Have drooled over your plinths pics many times.
Will try getting something built and if I am unable and you still would like to help me I will definitely take you up on that offer  :)