Wood Plinths: removable armboard or no armboard?

[nickbaba]

I'm putting together a design for a wood plinth for my next TT. I have the option to include removable armboards, the kind that are held in by 2 screws and can be swapped out and cut for different tonearms, or mounting the tonearm directly to the plinth.

Been googling this subject but found surprisingly little opinion online about which way is considered superior. My consideration is SQ overall. Of course the removable boards are solely for convenience, but can they also affect SQ either positively or negatively e.g. are they less stable, or perhaps do they offer opportunity to further decouple the arm from the motor/plinth?

I'm not planning to swap tonearms on a regular basis, but did think that the option to swap the armboard might make the plinth more flexible should I decide to change arms in the future. On the other hand, the arm I've chosen will sit on an SME-style sliding base, which does also suit other tonearms, and would still give me a degree of flexibility if it was direct mounted to the plinth.

But chances are I'll stick with the arm I have - so leaving aside considerations of convenience, which is the way to go for best sound?

[Wakefield Turntables]

Your coupling the tonearm board directly to the plinth by using two screws, albeit to a minimum but these screws will act as a conduit for motor vibration into the cartridge. Either decouple the tonearm completely or decouple the motor completely to solve this problem.

[Barry]

What is the turntable?

[nickbaba]

TT is a Garrard 401

Yes, good point that screwed on armboard will couple the arm to the plinth - I was thinking perhaps it left scope for de-coupling using something like rubber grommets or washers around/under the screws...?

but, logically your point infers that whether there's an armboard screwed down, or direct mounting, the outcome is the same: armboard is coupled to plinth.

So what else is a potential variable - solidity of the removable armboard mount?

If there's no difference to the 2 methods I'd lean towards having removable armboards as its simply more flexible for future arm changes.

[tlscapital]

Armboard material can make a huge difference in SQ. Even more so if your phono chain is "clear" (neutral) and "detailed" (transparent). Then according to the build of your turntable all the same. On my Thorens TD14X 'Super' DIY tweaked by me where the suspended sub-chassis design allow some of the good resonance to shine through, likely more so than on an "over dampened" turntable like a SL-1200 where the arm board material will have less to little impact on SQ if any.

I kept the original less "desirable" acrylic tonearm board my Thorens and SME3009 came with. I have tried DIYed beechwood armboard but got a "bassy" and "muffled" sound so took it off. Then tried a vintage original cast alloy SME armboard but got "bright" sound. So I kept my humble but perfect for it's SQ job acrylic armboard. I guess it depends on your tonearm and turntable build combination, tweaks and configuration matches that makes it "work" or not. Then there's one earbuds as well...

[Barry]

If you are using an SME, then the sliding bedplate already adds one mechanical interface between the plinth and arm.

However, since I presume you are using the SME spacer to place the arm tube at the right level to the platter, you could well replace this spacer with a new removable armboard. I would have it made from metal (aluminium) or a dense hardwood and secured to the turntable board with four screws.

[nickbaba]

Sorry, didn't mention that the plinth is a Russ Collinson (Layers of Beauty) Garrard plinth.

The sliding SME mount is so I can use Ortofon SPUs, as well as standard headshells, and still adjust overhang correctly. But with a decent sized gap beneath I could have it fixed directly to the plinth surface instead of to an armboard, and continue to use it with other tonearms in future (at least those that fit the SME style mount).

[Wakefield Turntables]

Panzerholz, or ebony work really well for this sort of thing. I use Panzerholz spacers on my two arm Garrard 301, I have a SME 3009 and a 3012. Ideally you should bond the spacers to the plinth rather than rely on screwing them into place. This increases the coupling interface between the spacer and the plinth and in theory dumping more nasty vibration into the plinth. Just a tip, it's probably better housekeeping trying to stop vibration from the motor in the first place, less vibration from the motor = less dumped into the plinth.

[Barry]

Which tone arm are you using?

[nickbaba]

Audio Creative Groovemaster ii

Thanks for all the armboard advice everyone - any thoughts on whether its better to have an armboard at all, or simply fix the tonearm to the plinth?