PLINTH DESIGN - Motor decoupling & Seperate tonearm pod

[Wakefield Turntables]

I've started looking into redesigning my Garrard 301 plinth. I have one simple question and would just like a consensus of opinion. My objective is to limit vibration getting into the headshell. My intentions as stated in the thread title are to decople the motor from the Garrard 301 and use a seperate arm pod. What it be fair to say that by using both techniques, it should maximise the chances of vibration getting into the cartridge? Sounds like the answer is pretty obvious but I would like comments and input from you guys.

Many thanks, Andy.

[kirstysdad]

God, what a nest of vipers to get into.
I'm only going on my own limited experience owning and researching about 401s. Aesthetically I like the separate arm "satellite" relying on mass/friction to hold it in position. But I guess then you are relying on supporting the whole shebang on something that will be rigid and non resonant.
Decoupling the motor is an excellent idea and there are a few out there (401s at least) who have done that.
I really don't know how far you would want to go- the cost/benefit analysis only you can answer.

In fact with a silent motor and bearing(s) you'd not need to separate the arm... ;) Like George Best, I would spend the saved money and time on booze, women and gambling.

[Wakefield Turntables]

Well that's one reply! I've already got a 401 in a MaxPlank plinth from Martin Bastin which decouples the motor and it has silent motor and bearing. I just want to see how far we can push the 301.

[kirstysdad]

Well that's one reply! I've already got a 401 in a MaxPlank plinth from Martin Bastin which decouples the motor and it has silent motor and bearing. I just want to see how far we can push the 301.

Lovely chap Dr Bastin.

[WullieD20]

I've built a few 401 plinths, with no reason the designs couldn't be applied to a 301 (although I'm not conversant with the 301!).

The one I currently use is a two piece beech ply. The motor unit is located in the top piece, with the base section attached, but isolated, with rubber mounts. The arm board is designed to accept a 9" or 12" tone arm and mounted on a pillar that is secured to the base board. This results in no contact between the motor board and the arm board (except via the rubber mounts), hence theoretically reducing any vibration between the two.....!

Another recent one is also beech ply, but is a one piece plinth arrangement with a 'well' where the arm board sits. The arm board is supported by a fabricated pillar, also utilising rubber mounts to isolate the arm board from the plinth / motor and has no direct contact with the main plinth.

Both sound fairly impressive, but I've never had the opportunity to determine if there is any significant advantage in sound quality when compared to a conventional plinth.

[WESTLOWER]

My only input is seeing a few examples of Bob C’s plinths
Decoupled arm pods within the plinth, materials used, decoupling the motor ..
It all makes a huge difference
His plinths are testament to that, as they take the 301 to giddy heights... obviously at a cost.

[Wakefield Turntables]

Adam, I've seen bobs plinths. You don't need to spend that sort of money. A little lateral thinking, careful material selection and a militarian approach to cosmetics should give you something very similar for a fraction of the price.

[WESTLOWER]

Adam, I've seen bobs plinths. You don't need to spend that sort of money. A little lateral thinking, careful material selection and a militarian approach to cosmetics should give you something very similar for a fraction of the price.

hmmm, not sure about that. Yes taking the attributes and reference points of well implemented design such as Bob C's plinths, may give you something that resembles one but sonically you will never know how it stacks up.
Saying "should give you something very similar" is pretty unfounded and hopeful.

But yes, I understand that taking similar design approaches into consideration will give you something... may even be better...who knows!

I personally think the Bob C plinth Value for money in relative terms of what it does to the 301 and the craftsmanship involved.

[walpurgis]

Idler motor decoupling is limited by the need to keep the idler wheel in accurate contact at two points. If the motor suspension becomes too pliant, no doubt it would affect speed consistency.

You can separate the arm from a turntable, but you shouldn't try to isolate it mechanically, as any compliance will have an adverse effect. Rigidity is crucial.

[WullieD20]

Rigidity is crucial.

A bit like fitting a Houdini then.....? . . :doh:

[walpurgis]

A bit like fitting a Houdini then.....? . . :doh:

No comment (well nothing that wouldn't step on a few toes ;))

[WullieD20]

No comment (well nothing that wouldn't step on a few toes ;))

:lol::lol: . . . :exactly:

[Wakefield Turntables]

hmmm, not sure about that. Yes taking the attributes and reference points of well implemented design such as Bob C's plinths, may give you something that resembles one but sonically you will never know how it stacks up.
Saying "should give you something very similar" is pretty unfounded and hopeful.

But yes, I understand that taking similar design approaches into consideration will give you something... may even be better...who knows!

I personally think the Bob C plinth Value for money in relative terms of what it does to the 301 and the craftsmanship involved.


All good points. I don't have Bobs skills and would never think I could produce a plinth like his. I'm happy just to improve what I've got and take it from there

[paulf-2007]

I built a two tier plinth for a 401, 30mm solid oak. Lower plinth supported on sorbothane and the smaller upper plinth with the chassis mounted, coupled to the lower with spikes into flat discs with indents to locate it. Arm pod mounted onto lower plinth. Spikes couple but the mass is almost doubled by the two levels.
My Denon DP80 has a different looking plinth on the same two tier principle on spikes.

[audioblazer]

Ihttps://live.staticflickr.com/65535/51293286453_7aa044b637_o_d.jpg

Separate arm pod . Can be troublesome to level armpod if your Tonearm tower for VTA adjustment is too tight. I have a Thomas Schick TA on a Reed armpod . Every time I adjust the VTA , my alignment will get shifted

[audioblazer]

Separate Reed arm pod with Thomas Schick Tonearm . VTA adjustment tower is too tight . Everytime I adjust VTA , alignment will shift .

https://live.staticflickr.com/65535/51295111005_3828d43268_o_d.jpg