SL1210 - SDS, Technics, Herbies's way or a combination?

[AlexM]

Thanks Ian and RD,

I am currently having a listen with the SDS and Herbie's way, without a another mat under the SDS. First disk on was Yello - Stella and wow! suddenly lots and lots (possibly too much) of bass. Sounds promising, but a little ponderous. I then noticed that the SDS carrier on spinning when I stopped the platter, in the manner of the wheels of an LA gangster's ride with spinners .

That obviously can't be right - if there is sod all contact between the platter and the mat then nothing much is going to be damped, but maybe also less is transmitted. Anyway, I added my Mitchell engineering clamp to lock the assembly together. Aahh... now we're getting somewhere!. Still very nice bass weight, but less bloat and it all seems like it's under much better control.

I'm listening now to Don Grusin Sticks and Stones, which features a lot of quite prominent low bass on the DX7. I notice that the low, low notes are ringing out and very nicely extended. I've not heard bass like that out of my combo before - I always thought it sounded a little lightweight and thin before. this is a very marked difference indeed. Bass is now solid and deep, and timing nicely too.

Unfortunately my experiment was 'contaminated' as I noticed that the tracking weight of my cartridge was set way, way too high. I reset it by 'floating' the arm, setting dial indicator to zero and then setting the tracking to the recommended 1.8g. God only knows how it got screwed up or how long it has been like that, but it was probably tracking 3+ grams It was overstressing the suspension and moving the armature away from the generator - no wonder it was sounding rubbish .

I'm going to carry on a bit more fiddling, but am happy bunny for now. I will try an under mat to see what effect coupling the SDS to the platter better will have. I may also try some double sided sticky tape, or vaseline.

Cheers,
Alex

[krugdoktor]

Maybe your SDS is slightly dished (mine is). Try turning the SDS over. Also double sided tape helps (should be very thin and only used on 3-4 small spots. The SDS damps the platter very effectively which is amazing considering the lightweight nature of the SDS but only if there is metal-to-metal contact between platter and SDS.
Of course vaseline is another valid alternative but also only tiny spots!
Greetings from Vienna
Michael

[AlexM]

Yes, it does sit much better on the other side, at least the platter and mat are now rotating at the same weight. I think some adhesive tape might be good - I'll experiment.

Regards,
Alex

[Lynster]

Yes you've reminded me that my SDS was slightly dished as well and that it seats well and doesn't spin when the 'correct' way up. I also use a weight as my Mike New bearing can easily handle it so haven't needed to resort to tape attachment however thin. Really tight base and detailed sound in general.

[rubber duck]

I'd be concerned if the SDS sat inside the rim of the platter and didn't make proper contact on top of this. If it's dished outwards, turning it upside down will not ensure full contact with the platter, which surely means that the platter will not be properly damped. Adhesive tape will only prevent the SDS from slipping but not ensure it is flat.

[krugdoktor]

As written before the SDS should make good large area contact with the platter (metal on metal). If it is dished (usally only very slight) and sits inside the raised lip of the platter a little pressure on the center of the record (weight or Michell clamp) should be enough.
A simple test is to tap the platter on the edge, if it rings, reverse the SDS, tap again, then choose the quieter side. Slippage should not be a problem, if so, three or four "points" of a (small!) amount of vaseline should suffice.
Anyway the SDS-Herbie's combo is a good one. Still a Mike New platter and bearing is a LOT better.
Greetings from Vienna
Michael

[rubber duck]

Surely a better tap test would be compare the SDS with the original thick rubber mat? I haven't tried the SDS but I would be very surprised if the platter is better damped with the SDS. Perhaps someone with the SDS and original rubber mat can try this and report back?

[krugdoktor]

I tried it way back then. The recomendation then was to use the Herbie's on the platter without any additional damping.
This did not work because the height adjustment of the tonearm did not go low enough. Also the "tap-test" produced a pronounced ringing. The ringing was reduced with the original heavy rubber mat (and the sound was better) BUT adding the SDS under the Herbie's was a revelation.
After first unpacking the SDS I was underwhelmed because it was so light and "flimsy", but as always the proof is in the listening and the SDS-Herbie's combo was a lot better than the thick rubber mat (which was btw a lot better than felt or an old Audio Technica ceramic mat).
To make matters worse, now I use an SAEC aluminium mat on the MN platter and this is the best mat I've ever had! Unfortunately the SAEC does not fit inside the rim of the original platter.
Greetings from Vienna
Michael

[Cycleallday]

Yes you've reminded me that my SDS was slightly dished as well and that it seats well and doesn't spin when the 'correct' way up. I also use a weight as my Mike New bearing can easily handle it so haven't needed to resort to tape attachment however thin. Really tight base and detailed sound in general.

I have never encountered an SDS mat but being an engineer I know my steel. If the mat is dished one side then it is dished the other (concave v convex). In either state putting tape or any other non adhesive between it and the cast alloy platter is a waste to time - once bent steel will not straighten and will simply pull away from the taped bond. If sds needs direct contact to work it must be perfectly flat to allow a weight/friction contact over the whole of its surface area or be properly bonded to the alloy. If you have a dished mat return it to sds as they are obviously charging a high price for a perfect disc and yours is not..

[Lynster]

If you have a dished mat return it to sds as they are obviously charging a high price for a perfect disc and yours is not..

The term 'dished' is probably a bit over the top but I was responding to another member who had previously used the term. The difference would be only a few thou at most and only light finger pressure is needed to ensure full contact one way and no pressure the other so the mat may as well sit the latter way up. As I understand it, the platters are cast and not always surface perfect either (which doesn't matter with a conventional mat) but with even with the weight of the record itself let alone a record weight, the SDS mat and platter contact well. In any case the point of the thread was how the combination sounds and that's excellent so mine won't be going back!