2. analog
  3. 1334862909

Technics SP-10 mkII speed adjustment question

Hi,

I'm on my way to complete my Technics SP-10 mkII project. Actually, a friend of mine, a professionnal audio technician, is working to upgrade the PSU, which is done but a small adjustment on the speed must be done and he need some cue on this issue.

We already asked Bill Thalmann, Artisan Fidelity and Oswald Mill audio. Plus, I'll post on DIY Audio today. We'd like to get the answer as quickly as possible to finalized this for the week-end. Hope someone on Audiogon can help.

Here's the message from my technician:

"Hello,

I'm an electronic technician and I do repair for audio equipments, vintage, hifi pro and more. I have a client here that brought me his turntable Technics Sp-10 MKII to fixed. I have a little question about it and he gave me your email because he pretended that you have some experience with this kind of materiel. So, hope that you can response my technical question.

I replaced all capacitors in the power supply and a big solder job. I checked for defect solders or capacitors on the circuit boards inside the turntable and I tied to do the adjustments . Everything seem good right now, the turntable work fine. I tried do do the period adjustment with the VR101 and VR102 potentiometers like in the service manual ( see attachment, Period adjustment method). When I looked the stroboscope at the front of the turntable, It's pretty stable but I can see a tiny rumble at 33 1/2 and 78 speed. 45 is the more stable speed for the stroboscope. So, I fixed the phase reference with T1 at 18us of period and I try to do the period adjustment at the point test T and S on the board with the O point for reference. When I put my scope probe on the T point, I can observe the stroboscope running. It is not stable at all. If I pull off my probe, the stroboscope is stable again. So When I have the 2 probes at point S an T at the same time to do the adjustment, it's impossible to fixed the wave T because it going right to the left on my scope. When I turned the VR101, the T wave going faster or slower but never stable. I tried to ground lift my scope, plug it into the same power bar and try to pull off the reference at the O point. I can't have a setup that I can see a stable T wave in my scope with the one that I can do the right adjustment. Why? Is there a problem with the turntable or maybe it's a incorrect probe or ground setup? Please let me know what you think.

Best regards"

Thanks for help,

Sébastien
128x128sebastienl

Showing 12 responses by sonofjim

sonofjim
557 posts
 
I've worked with both Bill and Chris and have found them both able and affable. I've also corresponded with Jonathan a couple times and personally would never do business with him based simply on his smug and condescending attitude. This is not rocket science and personality counts too.
sonofjim
557 posts
 
Sebastien,
The mat in my system picture is the Boston Mat ll. As Lewm states, it sounds great on that table. I also have the SAEC SS300 and like it a lot. I can't really pick a favorite on this one but they both are a better weight for the mkll than the Micro Seiki Cu180 IMO. The SAEC is out of production and may be a little tricky to find. The Boston is in production and affordable.
sonofjim
557 posts
 
Sebastien, Sarcher,
Yes I have tried the CU-180 with the mkll and did like the sound. I have two CU-180s and currently use each on custom MKlll tables. I thought the mkll sounded more dynamic and alive with the Boston mat ll, which BTW is an upgrade from the mat l, and the SAEC SS-300. The SAEC is actually closer in weight to the Mat ll than the CU-180 which does weigh 4 lbs(essentially what a TT weights mat weighs). Both the SAEC and Boston mats are closer to the original mat weight. I prefer the CU-180 on the mklll with it's considerably greater torque. The Boston is affordable and sounds great, no worry about counterfeiting.
The SAEC I believe was made with the MKlll in mind and is Steve Dobbins recommendation. Believe it or not, even though I have the SAEC I haven't yet gotten around to trying it on a MKlll as of yet.
sonofjim
557 posts
 
Pryso,
My system pictures are so out of date that I've considered just taking them down. Both those tables are gone and have been replaced with a pair of Thalman redone MKllls. One is in Chris Thornton's large constrained layered plinth, the other is in the Dobbins plinth utilizing only the platter and motor unit. Both plinths are dual armed. I'm still in the process of setting all this up and may get around to posting better pictures at some point when finished. Tonearms are EPA 500 (6 different wands), an exotic German carbon fiber arm, SME 312s Magnesium and soon a 12" Reed 3P.
Lewm,
I wasn't aware of this mklll mod Bill is doing until now. Please post all you learn on this especially if you have it done.
sonofjim
557 posts
 
Lewm,
The EPA 500 is now on the Artisan Fidelity plinth done by Chris Thornton. The main advantage of this arm system is it's flexibility. I got it to try multiple vintage/affordable cartridges. Currently I have five combinations set up that can be interchanged in about 30 seconds. It runs counter to common thought on these forums with it's limited adjustability(azimuth) and mutiliple connection points. You'd be surprised how good it sounds though. That being said, the modern premium arms are better of course. I'm anxious to try the 3P, possibly with an Allnic Puritas or Miyajima Shilabe. Now I'll forever have this mklll mod idea planted in my head too. It never stops does it?
sonofjim
557 posts
 
Sebastian,
No, I never changed anything about the mkll to use a CU-180. As far as adjusting speed on the mkll, I don't even know if it's possible. I'm not that technically knowledgable but there's no pitch control built in and the speed is quartz regulated. I liked what I was hearing with the Cu-180 but given it's weight, it made sense to me to use a lighter mat which theoretically should allow the platter speed control to function in a situation closer to what it was designed for. Both the mkll and mklll are overbuilt but the mklll much more so. The added mass of the CU-180 doesn't concern me on the mklll and pitch control is present though I've never needed it. I imagine the CU-180/mkll combination may work well without reason for concern. Readily available at about $200 though, the Boston Mat ll would be my top recommendation for the mkll. I'm just a guy who's used all this stuff and by no means an expert so take this for what it's worth.
sonofjim
557 posts
 
No doubt the CU-180 will be a big step up from the stock mat. I think you'd notice similar improvement with the SAEC SS-300 and the Boston Mat ll. These mats you may also want to try in the future. This is one tweak that is quick and easy to perform and as you've already seen the results can be fairly dramatic. At $200, I would still recommend trying the Mat ll. IMO it gives the table a more dynamic sound.
sonofjim
557 posts
 
Lewm,
The Dobbins treatment is not an irreversable step. He did the same with one of my mkllls and sent me back the chassis housing which can be reinstalled with about 3 bikes work he tells me. Not that I ever will but good to know. It's a great performer in it's current form. I also am soon sending my other MKlll to Bill for the Krebs mods so within a month ro two can compare. I expect roughly equivalent performance. We'll see.
sonofjim
557 posts
 
Sorry, that's 3 hours work. I'm on a weekend bike ride to benefit MS with my wife and must subconsciously have bikes on my mind.
sonofjim
557 posts
 
That's one of the best things about the sp-10 tables IMO, their flexibility. As far as the desecration of an heirloom goes, I look at these as my long term tables. I bought them to use and if I can do something to improve the performance it make sense to me. I haven't heard a table that sounds better when these are well implemented. I don't believe either Bill's mods or Dobbin's will decrease the financial value. I see Dobbins plinthed MKllls sell for similar prices to the spec variety. It was really the fact that Steve told me the process could be reversed that convinced me to go ahead with his. It's about the quietest most solid table I can imagine. I really wouldn't be surprised if Bill's mods accomplish very nearly the same result. I don't think you could go wrong either way. I'm not sure what table Dover must have if he finds the mklll uninspiring. It must be an awesome machine. Good for him if so. Meanwhile, I can't imagine being happier with my own situation .
sonofjim
557 posts
 
Lewm et all,
Sorry, I missed this thread initially. I have heard the SP-10 mklll with Krebs mods. In fact I have it in my system currently. I had some mechanical issues getting the table reinstalled in it's current Artisan Fidelity plinth but having resolved those it's running very quietly. I'm very happy with it's performance at this point.
I also have a mklll in a Dobbins plinth which has been my reference as far as silent operation is concerned. I would say the performance of the two tables is very similar at this point. It's hard to imagine better vinyl playback or machines more user friendly in everyday use.
Which would I recommend? Both. If carried out to their ultimate endpoint, both designs are reference quality in my opinion and a winner would be hard to chose. It may depend more on the look you're after. Hope this is helpful in some way.
sonofjim
557 posts
 
Albert,
I apologize. I'm not saying that the performance was the same before and after the mods. I'm saying that the mklll with Krebs mods and the Dobbins style direct mount produce similar results. Yes I had issues with rubbing on the chassis and even sent the table and platter back to Bill after the mods. He ran it out of the plinth for two weeks without issue. When I got it back I was more careful putting it back into the plinth to make sure it sat flat and not over tightening anything. I now believe the chassis was torqued or slightly twisted when the rubbing was occurring. It now run very quietly rivaling the direct mount in silence.
To me this is a question of eliminating noted or perceived performance issues with the original table(direct mount) or mitigating these issues with modifications, band-aides if you will. In my experience the band-aides are quite effective. I think it makes sense because both methods address the same issues.
I do agree that ANY rubbing or friction completely eliminates the benefit of the modifications which is why I went to such lengths to figure out the problem. Kudos to Bill for going the extra mile to address that.
I don't want to offend or argue with anyone. I've worked now with all three major plinth makers to good end. No single product has been perfect in every way but all work very well with tweaking. That's the nature of these vintage machines. The headache of getting them maximized is rewarded in the end. It's been a long journey for me but I finally seem to have reached a satisfying end point.
More to discover