Building high-end 'tables cheap at Home Despot II

Lew,

To give a bit of background, I'll take you back several years. My first e-mail to Jean expressed an interest in building a turntable from cement or machine grout. I abandoned that project shortly after, but the idea always stuck in my mind. Later, when slate hit the scene, I remembered the idea, and looked for similarities. There were many, and working with slate appeared at first glance to be easier. Shortly after that, I started my current project which makes heavy use of slate.

What I have learned, so far:

1) If you combine plinth materials, (I haven't) be sure to study which one should go where. I say this because slate is astonishingly effective, and it should be used in those areas that generate the most noise and vibration.

2) Building with slate isn't an easy road to travel. If your project is complex, there are so many issues to be aware of that it boggles the mind. Is it flat enough? What glue should be used? The list goes on. Also, using slate is a lot harder and slower to work than wood or acrylic. Still, it can be done with normal tools, unless you require extremely precise cutouts in your design.

3) Most mistakes are expensive ones. A small error can quickly take you past the point of no return, so be very methodical in your approach.

4) Slate is the most effective constrained layer material that I have ever used. I mounted a motor directly on the surface, and could not hear it with a Litman pediatric stethoscope from less than a centimeter away. It is very impressive in that regard, but not dead like lead.

5) Soft slate works great. If you happen to lightly chip it, it is easier to fix than some harder material.

6) It's pretty, too. ;)

Regards,
mosin

Hi Everyone,
Well it certainly seems like old times a'brewin here.
Mr. JStark wrote:
"I do apologize if some of you find it not on topic.
just sharing some ideas that worked for me. Not a Lenco project but some techniques will be implemented in that project as well."
No apologies needed at all on this. Your experiences in other facets of plinth building or other "Non-Lenco" areas are quite welcome.
Not far back in the posting, Jean and I were discussing the merits of servo-controlled Direct Drives. So go for it, by all means.

After reading a good bit about the slate upsurge here and elsewhere, I'm certainly rethinking my intended use of a doctored marble surround in a traditional Baltic ply/mdpb plinth. The reclaimed marble, which I have tons of, was going to get internal bore-outs with epoxy fills before fitment to a reduced size traditional plinth. However these heroics with unknown prospects in reducing marble's resonant ringing properties might not be worth the effort.

Maybe a good compromise in choosing a slate quarry would be something along a "Baltic" pedigree. :)

Oh Lew, I believe Jean's use of use of acrylic is not aboard any of his plinths, but is used in conjunction with marble as an "underfoot" base.

Sail on, guys!

- Mario

"Oh Lew, I believe Jean's use of use of acrylic is not aboard any of his plinths, but is used in conjunction with marble as an "underfoot" base."

Guys,

My last turntable used acrylic over wood, and it is quite effective.

mosin

Hi Mario,
good to hear from you. Always a pleasure.
Thanks for understanding. That was my point exactly.
We can all gain from each other experiences.
(I am sure my MMF-7 arm-board looks familiar. LOL)

My take on use of wood, MDF or ply. is that it is relatively easy to work with and effective. Its only drawback is that you need mass to get the most out of it ( For truly great design I would not go below 65 pounds). I sounds great on triple layered plinth too (I have tried that - experiment is more like it) but it leaves you only the after taste that won't go away. I am no builder or anyone that should be taken seriously in TT design or someone that has the know-how. I build TT for fun and my own satisfaction and use materials & techniques that make most sense and are within my reach and skills.
Using slate might be too time consuming and costly to make it right. Slate is difficult to work with and fragile. It can get complicated and fast if your design isn't anything but simple. I personally would not take upon myself to use it in my projects. I do however have access to a 'Soapstone' and guy who can and will turn my vision into reality. But how would that work in Lenco plinth design - sound wise is everybody's guess. But it might be something I may explore in the future.

Cheers and
happy listening

Mariusz

To join in on the discussion of alternate drive systems, I want to remind everyone that I have never written that one cannot obtain good results from a belt-drive, just that they are inherently inferior to the other two drive systems (once the bugs have been worked out), and that from an engineering point of view - that is engineering TO A PRICE, as engineering is meant to be - belt-drive is a failure as it requires a much larger investment to achieve idler-standards (assuming they can be achieved) than a sonically equivalent idler-wheel drive. I've often been on record praising the AR 'tables, Roksans, and such-like. For producing decent 'tables on a budget, the old platter/bearing, motor/elastic band solution can't be beat, nor profits, which is why they dominate/d (coming soon to a theater near you ;-)).

In this vein, I just picked up an irresistable belt-drive: a very rare "Unity 1 Rotary PLatofrm", which is as impressive as it sounds. It sports a solid brass platter, with most of the mass concentrated on the rim, which weighs in at 15 pounds! Worth its weight in gold. It is fixed to a truly superb main bearing, made of a sort of steel of extreme hardness, as neither it nor the bushings show any sign of wear whatsoever. Something is laser-imprinted into the metal of the shaft. Other than that, it is a classic belt-drive with a motor and belt. Story is it was manufactured in the '80s, was too expensive to manufacture (brass alone worth its weight in gold) and so carried a higher price-tag than people were willing to swallow, and the fellow went bankrupt. But, some day when I'm done with other experiments, I'll rebuild it into a plinth, polish up that brass, have an acrylic mat made, and set it up with a tonearm. It'll be fun, and hopefully musical!

There are all sorts of problems with slate - marriage of surfaces - Lenco-to-slate (regardless of the CLD nature of slate, it is still stone and so hard, which means metal slapping against stone as no surface is perfect) and slate-to-plinth - the inability to Direct Couple, not to mention the long list of perils listed by Mosin and so on - but I'll give it a go when I have time (still working on Reinderspeter's top-plate). The traditional recipe, i.e. wood, still represents the best real-world solution, and though this requires quite a large platform, the Direct Coupling absorbs the noise away from the 'table AND the vinyl (magically ;-)) to excavate the mighty Lenco/Idler and DD and even belt-drive potential. One gets used to the size: way back when I built the Canadian Rustic I thought it was huge (now seems quite puny), then came the Giant Lenco which now in the context of an even larger plinth (and certain humongous belt-drives) looks just reasonable, and now I have the Ultra Lenco which now seems just normal. Of course, carrying it is a bitch, but I wouldn't want to sling a Walker into my car either!!

I hooked up a pristine H-K Citation Twelve Deluxe (powerful vintage dual-mono SS amplifier) to my Yamaha NS-690s, hooked THAT up to my Ultra Lenco/restored main bearing, fired up Nine Inch Nails "Pretty Hate Machine" and thought I was being hit by an earthquake (I rushed to the volume control) the house shook so hard!! The dog ran for cover. Astonishing how much powerful and DEEP bass (like fleets of submarines sailing at depth among depth charges in my living room) the Lenco can force smaller speakers (the Yamahas are average-sized 3-way stand-mounters) to produce!! Meanwhile, all the itty-bitty details continue to remain clear above it all.

Anyway, have fun all, more to report soon-ish!