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
You're right, but was that one, or any model in the DD series, ever supplied with the CU180 mat, OEM? They also made the DDX-1000 and DQX-1000, minimalist direct-drive designs that I know for sure were supplied with rubber mats, had relatively lightweight platters.
To Micro-Seiki CU-180 owners:

Do you use your CU-180 nude or with another mat on it?

Sébastien
I just received my Micro-Seiki CU-180 mat and the improvement over the original mat is amazing! I can't believe it. I had to call my friend Francis to tell him the feeling that I've got. It's like moving from a $2000 amplifier to a $15 000 one. I was not ready for this. Imagine, Albert Porter told me that he hesitated at first to go with that mat that, we must admit, is pretty expensive. I bought mine new in box for $680 USD, more than twice the price of the Boston Audio mat 2.

Here's the improvement: better bass response, more dynamic, high that are more present and natural and all these advantages even at low volume. Also, it seems to bring a slightly wider soundstage.

Concerning the speed issue with this 4 lbs mat, I can't notice any significant change. The speed is still spot on. I was expecting the start and the stop motion to be considerably more slower but it is not the case .

I highly recommend that uprgrade to every Technics SP-10 mkII or mkIII owners.

Sébastien
Sebastien, Glad to hear you like what you are hearing. I was just as surprised as you when I got mine. Enjoy.

Sean
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.