Another Garrard Plinth

[Rajiv]

Hi,

Pictures of my new plinth for the Garrard. It is built up with four layers of 3/4 inch marine ply. The tonearm base is separate from the motor board.

Was inspired to go this route(separate tonearm base) after reading Kuruvillajacob's thread.

http://www.hifivision.com/phono-turntables/38342-successful-completion-arm-pod-lenco-l-75-a.html

The plinth needs to be polished/varnished and the SME 3012 has to be mounted. Should be done this weekend.

Regards
Rajiv

 

[denom]

Looks good Rajiv. Pls share details of the footers & reason for going for them.

Would appreciate a video of the TT playing music

 

[prem]

Hi Rajiv

Looks cool. Did you get the plinth made locally? Any reason for using marine ply over hardwood? How does one decide on the number of layers used? Why four? Is there any specific reason?

 

[malvai]

I am using 7 layers of Marine Grade Plywood... actually 6 layers of marine grade plywood and one layer of MDF... it sure sounds good!

 

[stevieboy]

Looks good Rajiv! Do post impressions of the sound on this vs the single ply loricraft style one you had earlier.

Is the armpod one square at the end or attached to the long rectangular wood piece adjoining the main plinth?

Regards

 

[Rajiv]

Hi,

Pls share details of the footers & reason for going for them.

The footers are solid hardwood 3"X2" blocks.

I have been using wooden blocks under the TD124 and find that they add a little more life to the sound compared to the rubber isolation feet I was using before, so I used the solid wood blocks for this plinth too. The 3"X2" size also allows me to try squash balls or add another sub-plinth similar to the skelatal plinths of Loricraft and others.

Did you get the plinth made locally? Any reason for using marine ply over hardwood? How does one decide on the number of layers used? Why four? Is there any specific reason?

The plinth was made by a carpenter locally. Good hardwood in the size required is expensive. Marine ply is a good alternative,as it is hard and dense.Also, the layers of ply should provide some form of damping for the vibrations of the motor.

I had previously used a plinth using six layers of ply (similar to Manav's) but found that I prefered the sound of the Loricraft type squash ball suspended light top plate type plinth. So,this time around I went for something in between . This plinth is medium mass similar to the one I have the TD124 in. Let me see how it sounds, the fun is in the experimenting.

Do post impressions of the sound on this vs the single ply loricraft style one you had earlier.

Is the armpod one square at the end or attached to the long rectangular wood piece adjoining the main plinth?

Will post impressions once it is set up.The armboard is the long rectangular piece adjoining the main plinth. Got the idea from here.


Norvald Dahl

Regards
Rajiv

 

[prem]

Thanks Rajiv. I look forward to your impressions on the sound once the table is up and running

 

[aks07]

Beautiful job Rajiv.

Just thinking would Mild Steel make a good plinth material? Say a thickness of about 45mm? Such a thick steel plinth will be very rigid and weigh about 65kg for a size of 300x600x45mm.

But I dont know what it will do with the internally generated microscopic motor and platter bearing noise. You probably need to think of a way to damp this noise or transfer it out of the plinth. Would heavy rubber lining and inverted steel cones help in getting the micro vibration away?

I have CNC Plasma & Oxy cutting machines in my factory. I can have any thickness of steel between 3mm to 63mm cut to desired profile within a tolerance of 0.5mm depending upon the process and thickness.

The plinth could be finished in powder coating or if you fancy chrome plated.

If you are game for it, and provide a drawing, then I can cut a profile and send to you for experimentation.

Added later:
I was looking closely and think if not the entire plinth then just the Tonearm base could be made of steel. This way we dont introduce the motor noise.

 

[jls001]

Just thinking would Mild Steel make a good plinth material? Say a thickness of about 45mm? Such a thick steel plinth will be very rigid and weigh about 65kg for a size of 300x600x45mm.

My guess is MS would ring to unacceptable levels. Amongst metals, aluminium is supposed to ring the least.

There was this audiophile from NCR who literally carved a plinth for his Thorens TD 124 from a single billet of aluminium. Final weight of the plinth being around 35 kilos.

My personal idea of the ultimate plinth is one carved from a solid block of hard wood

 

[aks07]

My guess is MS would ring to unacceptable levels. Amongst metals, aluminium is supposed to ring the least.

There was this audiophile from NCR who literally carved a plinth for his Thorens TD 124 from a single billet of aluminium. Final weight of the plinth being around 35 kilos.

My personal idea of the ultimate plinth is one carved from a solid block of hard wood

As mentioned if the noise is transferred away then you have a very rigid plinth. Cones come to mind.

Next year, and if the economy picks up, I am planning to add a Bystronic laser cutting m/c. Then we can cut aluminium, amongst other metal, with extraordinary precision but the thickness would be limited to around 22mm.

 

[denom]

Thanks Rajiv for the explanation. Pls do post your observations & pics when the plinth is completed & the TT is playing sweet music.

Enjoy

:thumbsup:

 

[malvai]

@Rajiv, I find that the top end is not as extended as what I have on the Clearaudio... could it be because of the dense 7 layered plinth?

Your comparison with your earlier plinth might just answer my question.... waiting for your impressions!

also, i feel that having the tonearm on the plinth itself might just be a better idea overall... I find that the sound is a a tad more 'solid' and defined...

 

[jls001]

Only for info: WIP pictures of a plinth for a 301 I am helping a fellow forumer make:

1) Top view

The arm hole to the lower left is for an SME 3009. The round hole to the right is for a Micro Seiki MA 202 10 inch arm.

2) Close-up of cut-out

One more layer will be added at the bottom-most. Each layer is 18 mm plywood. Glueing to be undertaken by the owner. He will also decide on the finishing.

Plinth design is from here. The cutout for the top two layers didn't fit so I ended up modifying the cut-outs for the top two layers a bit.

 

[Rajiv]

Hi,

Beautiful job Rajiv.

Just thinking would Mild Steel make a good plinth material? Say a thickness of about 45mm? Such a thick steel plinth will be very rigid and weigh about 65kg for a size of 300x600x45mm.

But I dont know what it will do with the internally generated microscopic motor and platter bearing noise. You probably need to think of a way to damp this noise or transfer it out of the plinth. Would heavy rubber lining and inverted steel cones help in getting the micro vibration away?

I have CNC Plasma & Oxy cutting machines in my factory. I can have any thickness of steel between 3mm to 63mm cut to desired profile within a tolerance of 0.5mm depending upon the process and thickness.

The plinth could be finished in powder coating or if you fancy chrome plated.

If you are game for it, and provide a drawing, then I can cut a profile and send to you for experimentation.

Added later:
I was looking closely and think if not the entire plinth then just the Tonearm base could be made of steel. This way we dont introduce the motor noise.

Ashok,thank you for your offer to build a plinth with mild steel. I will have to do some more reading/research on metal plinths before taking you up on your generous offer of making the plinth for me. Your suggestion of cones to drain away vibrations should work.

Regards
Rajiv

 

[kuruvilajacob]

Dear Rajiv,
Nice to see a wonderful new plinth. I will be in chennai on the 2nd, if you are free, I would love to come and listen to the new venture. i can share a lot as i have also recently made a few plinths for two Dual 1019 and a very old Dual type 1004 of the 1957 era.