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
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