Feb 6, 2019 7:35:59 GMT 12 neilsan said:

After I was given my SP10/2 I looked into isolators as one of the feet on the 10 is faulty.
Bought the Extra Large Bright Star IsoNodes, screwed the 10's feet right in and don't have any trouble with feedback now.Also used them under my 401 which also tightened up the bass.

Hi neilsan - does your SP-10 have a custom-type plinth base? In wood?

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i was about to ask a similar Q.

what feet on your sp10 neilsan ?

the little pads on the bottom of the motor cover ?

my sp10 sits on two layers of black diamond cones

FWIW - I use these (or similar) Sorbothane hemispheres under my amps, 50-70 Durometer hardness - www.amazon.com/Sorbothane-Hemisphere-Rubber-Non-skid-Adhesive/dp/B005JRMBLA/ref=pd_day0_hl_60_6/130-1979054-6856847?_encoding=UTF8&pd_rd_i=B005JRMBLA&pd_rd_r=0a92f197-299c-11e9-a1a9-5ba6a64d0911&pd_rd_w=wjatw&pd_rd_wg=8NfKQ&pf_rd_p=ad07871c-e646-4161-82c7-5ed0d4c85b07&pf_rd_r=KGKV2SM6EDFKZYJRX52G&psc=1&refRID=KGKV2SM6EDFKZYJRX52G

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SL1000. Mk2. Sorry should have said. The feet screw in and out for adjusting. I've screwed them all in and stuck the isonodes under them.
Neil

That's a rare & beautiful beast, neilsan.
Perhaps post a pic for us to drool over, on the TECHNICS SP-10 thread?

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The Mag-lev footers arrived - 16 days from Shenzhen, China.

Finish is VG-Ex.
The bottom portion is actually 2 parts which screw together (concealed by the grooving).

The bottoms have self-adhesive felt pads, which allow the footer to rock a little sideways - I may remove this, so that they sit flat.

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A CAD 'model' of the plinth + turntable.....

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Had some time today to rough out the plywood sheets - 5 layers x 17.5mm = 87.5mm total thickness.

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Just a random idea: Have you thought of giving the sheets a good soaking in Tung Oil? It gives a hardness and also looks good.

Hi SL1210 - I've never tried Tung Oil actually, but I believe that it's a nice, hard-drying traditional oil finish.

I'm going for something a bit more 'contemporary', a white 'blonded' wood look, something like this rack I knocked together hastily a few years back....

I think it should work nicely with the silver-black SP-10.

(In the 3D model above, the mag-lev feet are hidden inside the 'black' blocks.)

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This might give a more accurate impression....

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That closeup shows a lovely texture, and I can see why you would want to keep it at that.
Back on the subject of footers I have used Isonoe Footers in the past. They are essentially 4 little trampolines and work very well. It seems though that the maglev idea must be tried. I am definitely going to give them a go. I am sure you are on the right track with them. In concept a high-end turntable, any turntable actually, should strive for good speed and freedom from vibration. Easier said than done though! Massive plinth, damping material, and mag-lev footers should see you through. Given that you are starting with a direct drive and a known good one at that will I am sure be a very good end result.

A mock-up on the plywood cuts, with 12" & 10" tonearms.

First reaction to seeing the plywood cuts was that it is BIG - but looking at the tonearm brief (2 arms, 12" arm/s), it can't be any smaller I think.

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looks good !

Tomorrow is Cutting Day on the CNC router.

For interest, this is an exploded model of the cut & assembled plinth (with some small changes)....

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Feb 15, 2019 19:41:22 GMT 12 Owen Y said:

Tomorrow is Cutting Day on the CNC router.

For interest, this is an exploded model of the cut & assembled plinth (with some small changes)....

Is the design for the lower portion taken from a Roman Amphitheater? 

Hi SL1210 - good thinking!
The circular shaping is my thinking about how best to address rotational torque of the SP-10 DD mtr (see my 29 Jan post above).

Also, the upper layers are reduced in mass, getting progressively more solid at the bottom, which will have a 9-12kg stainless steel baseplate / 'noise sink' (see my 1Feb post above).

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CNC progress videos:

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OK, first problem encountered:

Kenwood L-07D tonearm:
Having never owned a Kenwood L-07D TT, I didn't spot that the Arm Height vernier wheel might be lower than the tonearm's mounting surface - ie the plinth top.
(On the L-07D the winding wheel overhangs the side of the L-07D TT, in fresh air - see below.)
The problem with our plinth now, is that the wheel hits the top of the plinth - we need a spacer of 4.5mm min. to raise the tonearm base.

However, this could mean potential problems with the tonearm being too high above the platter mat - even for tall cartridges.
Cartridge spacers (up to 6mm) would then be needed under the headshell.

Maybe a serious decision is required....

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How about machining a depression in the top of the plinth to accommodate the adjusting wheel.

should be relatively easy to do with your fancy router ?

is the kenwood a 9in arm ?

Graham - thanks yes, indeed, that's what we'll do I think.

michaelw - the Kenwood arm Eff Length is specified as 245mm (ie 9.65", same as FR64) - but I set it up at 250mm.

Other options:
1) headshell spacers which can/should be avoided.
2) chopping ~19mm off the RHS of the plinth, which would be OK, reducing plinth size a bit too, except that we already have machined-out internal cavities.

An aside....(warning, more engineering porn):
My resident 'engineer' lasercut some prototype 110 diam. spacer rings at work, in acrylic (as below) - which we won't use, but will be useful as templates to check the Kenwood hole spacings (which I have discovered are not EXACTLY at 90deg bolt circle spacings(!) - Problem No.2 to solve )
Poor video sorry, probably taken through safety shield I expect.)

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looking good !

It's probably a little late for this suggestion, but have you considered swapping the arms around? I think this works better. The plinth doesn't need to be so wide (just a little deeper) and you can have the winder hanging over at the rear. 

Sorry if this puts the cat amongst the pigeons...

Hi snewt - yes that's a good suggestion.

But I'd like to have the plinth flexible enough to use other tonearms too, incl. 2 x 12" tonearms if required.
And as mentioned earlier above, I don't mind the 'plinth' being a little wider on the LHS with the SP-10 sitting visually more centred.

I would have simply made the plinth ~19mm less wide on the RHS, if I'd spotted the L-07D winder issue earlier!

How does the Rega arm (with 3rd party c'weight?) sound, compared with say the Apparition?

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The offending arm-height winder wheel ....
(With 3.6mm Black acrylic spacer temporarily fitted.)

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If you can go in horizontally in line with the adjusting wheel position with a 50 - 60mm cutting drum it will make a very neat radiused depression to clear the wheel and look like you always intended it to be there !

Yes, good thinking Graham.

We weighed up that option but with plywood, I'll probably not go with a radiused pocket because of the glue-lines & just do a shallow flat pocket...

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That's a nice technical looking arm Owen. I take it the rod with the markings near the arm rest is the vernier scale? How much vertical travel do you get with the arm? And final question, can you adjust on the fly?