What has the check over revealed?

More than just the electrolytic capacitors?

I've replaced all electrolytics in both PS and Ttable.

Jun 24, 2020 8:32:12 GMT 12 neilsan said:

I've replaced all electrolytics in both PS and Ttable.

Hi neilsan - do you know what cap was used for the big 1000uF/80v first filter cap on the 32.5V supply?
Most punters seem to go for Panasonic FCs for everything else.

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Jun 23, 2020 17:32:59 GMT 12 Citroen said:

What has the check over revealed?

More than just the electrolytic capacitors?

Hey Citroen - I opened up the power unit just last night.
The 3 x output voltages (with TT connected) are all close to specif., within 1 - 1.5% - so nothing amiss here.

The 5v & 32.5v lines are regulated (adjustable discrete transistor ccts exist after AC rectification), but the 140V line is not.
Last night, the mains AC was 229vac & the 140v line measured 142v.
This morning, AC line was 237vac here & we measure 144v - +3%, still OK methinks, as the 140v line feeds only the 'logic' cct (control switching, etc).

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thanks for the photos and info, this is really interesting. I shudder to think how many sp10 units got junked over the years. I worked in radio for about 10 years, running studios and so on, and these units where everywhere around the country. the old community network stations all had fantastic studios, sp-10s and occasionally 1200mk2s in all of them, but through the networking years, so much awesome equipment got dumped, or mothballed into oblivion as the private network owners had no interest in the local studios, they just wanted to pipe in the network shows, and eventually the computerisation of everything took over.

It would bring a tear to your eye to see the amount of beautiful outboard studio gear, broadcast equipment, vintage microphones and SO MUCH VINYL that just got thrown away. It was criminal. But there must have been dozens of these units scattered around. I wonder how many were rescued.

Yes, there were heaps of SP10's in use, so don't pay over the odds unless it has been fully rebuilt as many will need work.

Pics of SP10s past.

If anyone recalls the radio mast (lakeland FM) at the top of the hill above the Waikato river in Taupo, that was the CRN homebase in the late 90s, and I worked as an engineer there. Discovered a double garage worth of records, just dumped in boxes, stacked up in massive piles and gathering dust. the whole lot had been swept up from stations around the country and just dumped in there until someone could be bothered to take them to the dump. I proposed we actually run a record fair and pick a local charity to raise money for, we could have sold them 'nothing over 50c' and still raised thousands, but the powers that be weren't interested. too much trouble. so i suspect when they bowled that old building it all would have been scrapped. modern day tragedy!

I also remember the massive AM broadcast facility out the back. Beautiful green powdercoated cabinets filled with giant glowing tubes, looked like a scene from a soviet power plant or something. That was very cool.

EDIT: sorry, derailing the thread here. BACK TO THE SP-10!

Capacitors - there appear to be around 30 of these in the PSU & PCBs under the TT.
At $0.70 - 0.80 ea, not a big expense.
However, given that the TT's speed control locks solid onto 33/45rpm with no sign of instability, there's no urgency I feel.

I checked the large & most easily accessible cap, the first 1000uF/80v filter cap on the 32.5v supply.
As you can see, it still looks OK..... (although a modern cap would likely have lower ESR & much smaller physical size.)




(ESR 0.03 - 0.04 ohms.)

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First, I need to figure out how to hook an oscilloscope onto the Speed Control PCB under the TT, while it's running - in order to check the 'Freq Generator' waveform (as per the Service Manual, which the seller was kind enough to provide me with a colour-copied, spiral-bound copy of).




I could build a nice jig like this - or alternatively just use some stacks of books





(The above stand was built by this SP-10 restorer.)

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Scored from a UK SP10 user, a mint NOS OEM mat

After swapping mats back and forth, spot checking vta etc. and much listening...

The Puresound is back on the SP10.

The fresh rubber mat brought a warm, rounded sound but it also smeared detail, shrunk the sound bubble, flattened dynamics and made everything a bit tubby.

By itself quite listenable but the gunmetal mat sent it packing.

Yes, those rubber mats can give a strong, warm lower-mid tone, but ultimately 'noisy' & fatiguing - in a hi-fi sense.

DarkLantern blog - darklanternforowen.wordpress.com

rubbery sounding

surprising difference between this NOS one and my old hard one.

like car tyres !

I see that ACOUSTAND AUDIO in UK offer a Technics SP10 Turntable Chassis And Platter Restoration Service. - for £210.


Original satin brushed finish restored (& re-lacquered).


Or any powdercoat colour that you may prefer.

DarkLantern blog - darklanternforowen.wordpress.com

Is it some quirk of digital photography that the satin finish above looks grainier than stock ?

Dont like the silver so much..black looks nice.

Feb 22, 2021 15:10:49 GMT 12 michaelw said:

Is it some quirk of digital photography that the satin finish above looks grainier than stock ?

Nah, it's probably just the pixel pitch of your monitor

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I prefer the silver finish.

I'm leaving mine as is

Feb 22, 2021 16:38:21 GMT 12 Citroen said:

I prefer the silver finish.

Silver is the new black

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For our Technics fanboys:
(from Stereophile)

OMA SP10 Plinth System
Specialty audio manufacturer Oswalds Mill Audio, aka OMA, makes tubed electronics, horn loudspeakers, and, for well over a decade now, high-mass turntable plinths (footnote 1). These plinths used to be made of slate, but recently OMA has produced an iron plinth specifically designed for Technics' SP-10R and earlier SP10MK2 and SP10MK3 direct-drive turntables.

The SP10 Plinth System is a single sand casting of hypoeutectic or "gray" iron. This is not your grandmother's cast-iron skillet melted down and poured into a plinth mold, but a more recent development. Gray iron combines high mass with exceptional rigidity and vibration-damping properties. On the SP10 plinth's underside is a web of cast chambers, each filled with a vibration-damping polymer. The casting is CNC-machined to precisely fit the SP10's chassis as well as an opening for removable armboards, which OMA CNC-machines from torrefied (ie, thermally modified) Pennsylvania ash wood. (Torrefaction involves heating the wood in the absence of oxygen, which removes from it residual water and volatiles, to produce a material with no biological activity—ie, it will never rot or soften.)

OMA claims that torrefying ash wood produces a material that is both extremely dimensionally stable—it won't warp or swell or shrink with changes in temperature and/or humidity—and has "superior acoustical properties." The armboards can accept tonearms with pivot-to-spindle distances of 9" to 12" or longer, and can be precisely swapped out in minutes.

Holes in the plinth's feet are tapped for M6 hardware. OMA supplies "basic leveling feet," but of course your every footer fantasy can easily be fulfilled. The plinth, available in clear lacquer or black powder, weighs 110 lb not including the turntable, and it's big: 26 1/8" wide by 4 1/8" high by 20 3/8" deep. The price has yet to be determined but will be under $10,000, which means that the combined price with SP-10R turntable will be under $20,000.

"I see music as a lifetime affair." [Rory Gallagher]

With the SAT arm and suitable cartridge you'd be looking at $50-60k



So it's gray iron !

Hope it works.

AFAIK my ony experience of "hypoeutectic" casting is in Subaru EJ25 pistons and they were rubbish compared to the previous gen's forged items.

Why didn't they use the same material for the armboard ?

An occasional series of famous SP10 users... Mr Kenny Everett courtesy of Techmoan

25 years ago a chap in Germany stashed some new Technics SP10 Mk2s.

Now they are seeing the light of day

€34,600 !  crackpipe pricing

aie-de.translate.goog/aie-plattenspieler-turntable-751.html?_x_tr_sl=de&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=sc

He can ask all he likes for them...make it 40k...Its getting someone else at the other end to think that it's a good price is the problem he will no doubt be facing!!

Review in LP International Magazine:

aie.de/pdf/Test751_LP_en.pdf

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