DIY TT motor mount advise

[dazed2]

Hi everyone, my first post here.
I've been itching to do some work on my PLanar 3 I got for a song. I've already rewired the tonearm with cardas wire sort of the Incognito way. During that process I notice how simple the Rega design is. Anyways I got to thinking of building a plinth but with limited budget.
Yes yes I know, there are many that insist that the Rega lightweight design is great, but hey this is DIY.
Anyways I decided to do the cutting board plinth. Its easy and simple for a first timer and it is really cost effective.

The stock motor on the PLanar 3 is the Airpax motor, not the greatest but I haven't gotten around to upgrade. I probably will change the motor, but I think before that I will probably make the Gleddon PSU or the NAIM PSU clone. They seem easy enough.

Now to the question. What would be the best way to mount the motor, given the constraints
1) No dual plinth design, I want it a one piece thing
2) reuse the stock Rega belt
3) minimize any and all vibration from the motor to the plinth

I was thinking of instead of the rega solution of double sided tape. I would mount it on say a plastic or if I can find some Carbon Fibre sheet and have rubber bumpers where the sheet is bolted to the plinth.
What are your thoughts?

[sq225917]

The double sided foam-tape is actually very good.

I did remake the plinth on my P5 using a hardwood block and mounted the motor via carbon/birch-ply/carbon laminate plate, which was siliconed to the plinth to make a mount that was very slightly compliant.

Was much quieter than the Rega set-up.

The carbon sheet was from Dragonplate.com

Here's a shot of the version on my P5 that lead to the re-plinth.

Turntable Forum :: Gallery

[dazed2]

Wow that looks nice.
Is there are reason you used a carbon/ply/carbon laminate?
I was just thinking of using Carbon itself, or even acrylic.
Oh instead of silicon (permanent) I was planning to just use rubber washers (grommets) on the carbon and screw them down to the plinth. Would that be as good?

[sq225917]

I used carbon ply because it's better damping across a broader range of frequencies than just the carbon itself- not much, but enough. The dissimilar materials help damping.

If you use washers and then screw them down you are effectively short circuiting their effect. Instead try putting some Fablon (self adhesive film) on top of your deck and then siliconing onto that. It's more than temporary, but will peel off cleanly when you want.

On my P5 the top surface was melamine so the silicon could be scrubbed off that no problem.

[dazed2]

I wasn't planning to squash the grommet... however I see what you mean.
I've also been toying with the idea of using the 5 1/4" floppy drive motor as the TT motor quiet, low vibration, and and precise bearings. But they are huge. I've already took two apart and have them running, I think just a resistor before power gets to it should be fine?
Anyways need to start cutting holes now...

[pmonti]

Please tell me if you can give me the distance between the center of the pulleys. Im tring to build one rega plinth preserving the original distance and i haven't the original rega belt. Best regards.

[dazed2]

pmonti, I measured 2 3/4" or about 67 - 70 mm from the centre of the pulley to the centre of the spindle.

However you have to cut a larger hole for the motor pulley as there is a HUGE tolerance allowance. The centre distances can vary as much as +- 1/8" in a circle. Remember the older designs used a rubber band to hold the motor so the motor was free to float.

Hope that helps