Building high-end 'tables cheap at Home Despot II


“For those who want the moon but can't afford it or those who can afford it but like to have fun and work with their hands, I'm willing to give out a recipe for a true high-end 'table which is easy to do, and fun to make as sky's the limit on design/creativity! The cost of materials, including 'table, is roughly $200 (depending, more or less), and add to that a Rega tonearm. The results are astonishing. I'll even tell/show you how to make chipboard look like marble and fool and impress all your friends. If there's interest I'll get on with this project, if not, I'll just continue making them in my basement. The next one I make will have a Corian top and have a zebra stripe pattern! Fun! Any takers?”

The Lead in “Da Thread” as posted by Johnnantais - 2-01-04

Let the saga continue. Sail on, oh ships of Lenco!
mario_b
So Jean, you're not going to give us the weight? You could at least give us a hint, like calling it the "39 cent" mod, or something like that, in line with the original "cheap" ethos of the original thread.
Nice mod Jean. The only thought I had was that if for some reason the 'bag' of pennies starts to swing it could affect speed stability - possibly use a more solid weight and suspend it in something to 'damp' it e.g. silicone fluid?
The pennies are for purposes of the experiment only, I thought this was clear: "After finding the weight you like best, simply hook your weight (which can be glued-together pennies, or a bolt and nuts or or or…" and "To those who want a finished kit-form TJN Mod, with threaded insert for secure bolting to the Lenco chassis with rounded lip which raises the string to the level of the arm (so pulling at a perfect 90-degree lateral angle at X-gram force) and which extends to below the motor so there is no fouling of the string/weight possible, machined brass weight with hole,..."

I am NOT pitching this kit to make money, at this price it's barely worth my while to go to the post office, it's only intended as a public service to help SERIOUSLY improve the Lenco sonics around the globe to, as I wrote, cause more Lenco fireworks/importune the competition, be it DD, belt or other idler, and again I say: heh-heh :-). I encourage those who want to roll up their sleeves and have some fun to do so, I mean really. Of course the kit will be standard in all my models, this is too fundamental and important.

Nevertheless, unless you intend on pushing it or operating it in a high wind, it will not start to swing in any physically-meaningful way. A related issue is finding the precise mass which will exert the most pressure, and so be the most difficult to move, without straying over into so much you start to wear out the wheel and cause various mechanical problems: anyone who has tried to substitute for the original, let's remember VERY delicate spring, with a stiffer one knows this simply doesn't work.

No physical system on the face of this planet is perfect, including the TJN Mod, but the EXTREMELY simple weight on a string substitution is SO much superior to the spring (and I'm talking not only mechanically but also sonically) - and, it will be found due to its extreme simplicity and effectiveness superior to any other solution - it is astonishing that in the seven years since this whole thing started, no one has thought of it. And I believe no one has because as a rule, people are far too impressed by the unnecessarily difficult, the unnecessarily complex (for this reason it's a large component in many audio manufacturers' marketing), and have forgotten about simple results, simply achieved. Effectively, it was so obvious and simple it was invisible.

This spring issue, as demonstrated to and witnessed by Salvatore (a virtual doubling of sound quality) is much more FUNDAMENTAL to the operation of the Lenco than any plinth and so on questions, which FOLLOW, not lead (i.e. it is the fundamental Lenco engineering - powerful FAST motor, flywheel-platter, idler-wheel - which makes it great, without this, the best plinths in the world & etc. applied to a belt-drive will only result in another so-so belt-drive).

So getting back to it: silicone baths and what-not are not necessary, do you see anti-bias weights on far more sensitive tonearms (in terms of importance/sensitivity to vibrations etc.) bathing in silicone fluid? Let's stick with my leading principle since forever, the KISS principle, the reason the Lenco itself is so great: Keep It Simple, Stupid. Not intended as an insult, but simply a good motto, especially in engineering.

I won't give out the precise weight/force I found optimal due to the reasons given - and already I can see all sorts of unnecessary side issues will end up dominating and eclipse the beauty of this simple solution - anyway self-respecting DIYers should embrace this chance at a fun experiment and DIYelves :-)!!

So let's get back to it: the TJN Mod is a weight on a string (KISS), and that string does not transmit vibrations, contract or expand, simple, effective, forever, and the weight, being a simple weight, will always hang with the same mass/force, steadily, since gravity does not vary on the surface of this planet, and string is not a spring. Those who implement it will have a GREAT improvement, those who don't won't.

So have fun y'all, I'll be leaving now and won't be back for quite a while, as a customer of mine always says, Roger & Out.
Jean; Thanks for the tip on how to further improve The Mighty Lenco. As you know, I am already extremely pleased with the Lenco you rebuilt for me and my particular Lenco is just a 75 pounder (i.e. presumably no where near the performance of the massive Lenco Reference). I really did not think you could make further improvements to this design but I was clearly wrong. Well done!
As tempting as it is to jump right in and do the TJN Mod myself, I think I will wait for your kit. It seems to me that $60 is very reasonable (in this hobby, this is a laughably small amount) and the kit will take the hard part (getting the weight right) out of the equation.
Once again: Thanks and well done.
I certainly would not want to argue the question of whether this new mod actually improves sound quality, which it may well do, but on the level of theory, I have a question: Why would one expect the string not to transmit vibration, as compared to a spring? Sources of vibration could be (i) the bearing of the idler wheel, (ii) irregularities in the shape of the motor drive shaft, or (iii) dirt or other on the underside of the platter that might cause the idler wheel to bounce a bit. The force applied by a spring to maintain contact between motor shaft/idler wheel/platter will vary according to Hook's Law, which says that F is a linear function of the amount of stretch of the spring. The force applied by the string to do the same would be equal to gravity less any frictional losses where the string touches anything. I don't get why (theoretically) the string would obviously be a better way to do the little bit of work (small force X a very small distance) that is required. I guess you are saying that the spring itself is a source of noise/vibration that mucks things up; yes?