LENCO - GL75 Project

[Wakefield Turntables]

Tonights Update - The Reference Lenco Pt XIV - More Fettling and a kick up the arse!!!

I've had some downtime and decided to do more research, get in contact with a few Lenco GURU's and kick myself up the arse and get a few little jobs done.

Tonight I decided that the tonearm cable needed a little fettling so I cleaned the RCA's and the earthing post. I've had the TYR tonearm cable for years and have never given it a clean and considering that it's been on my list of stuff to do for a while I thought I better get on with the job. I always polish with BRASSO and then clean away any residue with IPA and then finish cleaning with contact cleaner and cotton wool. The finished article.....

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I recieved another package today and managed to complete another task on the list this time it was... platter dampening rings. I ordered these from eBay for £13 and they arrived 24 hours later, that's quick!! Why bother? Well, the platter did have some imperfections when I polished it and they do hide a multitude of sins as well as adding an additional vibration control to the deck. I've been a firm believer in dampening rings for a long time and utilise them on all my platters which are usually bloody big heavy metal things. I've used them on my 301 for quite some time and they add a small but worthwhile improvement and hopefully will give me a nice return for my investment. I used three on the Lenco top platter and should compliment the aesthetics of black top plate and silver tonearm. I've taken a quick snapshot of what the platters will look like once on the deck.

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Now, the Jean Nantis TJN modded is either loved or loathed. Plenty of people seem to think it works others think it's complete bunkum. I decided to contact Jean and see how much this mod costs, well $75 is the answer and I honestly can't see how a couple of clips, some fine line and a small weight is going to cost that amount so it looks like I'm going to produce my own version. It's not high on the list of things to do at the moment and will only "live" on my Lenco if I can percieve a sonic improvement. Now to all those that think it's bollocks I agree that the theory is ropey but I still think it's worth trying. I'll probably start getting the bits together over the next few days/weeks and assess over Xmas to report my findings back. I've also contact Jean with regards the Post mod for the Idler arm. There seems to be several ways of doing this and I'm assessing which is best. I've tightened my idler arm slider as much as possible and it still rocks. It's designed to do this but it will produce idler wheel oscillation and instability when engaging the platter during operation.

As an aside I now need to start looking at coupling the top plate to the platter. I'm going to order some Marine resin and fill the top plate. I have a spare top plate to experiment with. This will add additional mass to the L75 and increase it's surface area so this will enable better coupling to the plinth. I will also fill additional holes in the top plate and determine where I can use some wood screws with washers to better couple the top plate to the plinth. So plenty to do over the next few weeks. I'll make a proper start with all this stuff probably in the new year. Let's just get the Jolyon bearing installed and have a listen to what we've produced so far!!!!


NOW Kai, some answers...

There's certainly a wealth of information and possible tweaks, but not many of them backed up by anything else than personal preference. I'm sure many of them would be scientifically hard to 'prove' even if one had the means, and most DIYers don't. For example regarding the top plate, I chatted with a local guy once who has built many Lencos for himself and others, and he was of the opinion bolting the top plate to the plinth through the pan is not an improvement, but kills the sound. It might be he just personally prefers some lively resonance, or on the other hand it could be by changing the path of the energy something detrimental really does happen. But even then there's so many factors, like plinth material and mass, what works in one build might not work in another. Biggest imporvement according to him besides the usual stuff of heavy plinthing and cleaning and relubing everything was to center the motor coils. Makes sense, the less vibration there is coming from the motor obviously the better. It would be interesting experiment to build a plinth where you could mass load the motor casing and isolate it from the rest of the plinth not through springs, but some other means of isolation or even have the motor pod not in any contact with the rest of the plinth at all.

Btw. what all did you do to get rid of the idler wheel oscillating? I'm having some of that myself, I can hear it through speakers if I crank the volume high enough, a sort of whinging oscillating whistle/whine. I suppose it's probably an idler wheel alignment issue - I aligned the idler wheel the best I could by eye, and it got better but then I started loosing torque. Thinking it was the alignment, I realigned it back to where it was originally, where it started making a bit of that noise again, but I got my torque back. Then the problem reappeared and in the end it seemed to be about the rubber grommet which had gotten tired and turning it 90 degrees got rid of the problem. Now I'm thinking realigning the idler probably was not at all the cause of the problem, but just brought the issue with the rubber grommet to surface. However I haven't gone back to fiddling with it, since it works fine now and the noise is really faint, I can't hear it all with listening volumes, I really need to crank it beyond that and be close to speakers to hear it. I'm also thinking trying to recondition the rubber grommet would probably be a good idea, but again, since it works and using wrong stuff for reconditioning might mean improvement at first and the rubber falling apart later, I haven't taken the risk.

I got rid of the wheel oscillation buy using the Werner Idler arm modification which costs 7 Euro. It works by using 2 larger teflon washers to replace the much smaller versions supplied by Lenco. Werner also supplies a small locking collar to which enables a better fit betwee the washers and the idler wheel. The Teflon has a very low coefficient of friction but still need either greasing or oiling (depending on your choice) I used 3-in-1 oil and the wheel now functions silently and with no oscillation. You may also want to do the Post modification to the Idler arm slider as this is an area of idler wheel oscillation. I think "alignment" is bollocks . All you need to do is make sure that the platter rotates at 33.33 rpm with a vertical non-oscillating idler wheel. Well I think if your Lenco is working well then leave it alone. Hope this helps.

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[Wakefield Turntables]

The project has tanked for the time being as I've done all the prep work for the deck I'm just waiting for the new bearing. I'm researching on LH and I have anothe 42 pages of thread to go through before I've officially "read" the entire LH forum. Any additional research will now come from individual websites. Come on Jolly where's the bearing.....

[Wakefield Turntables]

Tonights Update - The Reference Lenco Pt XV - The Loneliness of the long distance Lenco modder....

I've finally got the news I've been waiting for. The new bearing should be here in less than 7 days. I'm going to initially listen to the Lenco with the new bearing coupled to the top plate and get to know how it sounds. There have been many many mods over the last few weeks so I think it only appropiate to at least have some understanding of how the '75 sounds before I go any further with the mods. My research is still continuing at a pace and I now only have 36 pages of threads left over in the Lenco projects sections of LH to go and then I've read the entire contents of LF forum . I've realised that I need another top plate before I can progress any further with this project so I dusted off my spare Lenco top plate and stripped it down.

This is going to form the next stage of the Lenco Reference. This top plate will be properly filled with Marine Resin. All excess holes will be filled but I first have to determine which I'm keeping and which I'm filling. I have some rather neat ideas with regards what I want do do with this top plate. The tonearm holes will be properly filled and the speed selection will be filled and coupled to the top plate more effectively.

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I've come to realise that MASS is very important for getting the best from the '75. So I decided to do some experiments with regards measuring the mass of my deck and plinth. The bog standard un-modded '75 top plate is 4lb.


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See told you so... ....

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I've ordered some marine resin and will fill the void under the top plate and then re-assess the mass.
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The surface area under the top plate will be markedly increased which means nasty vibrations will sink into the plinth over a wider surface area which should improve the deck's ability to deal with spurious vibrations. Filling the voids also improves the coupling capability of the top plate to the plinth. Additional mass will be added. So far I know my unmodded top plate is 4lb, I have also weighed my Plinth and it comes in at 22lb, so I have a mass of 26lb's so far. This is measly compared to some of the 100lb beasts that inhabit LH . So, until next time....

[Wakefield Turntables]

Tonights update - The Reference Lenco pt XVI - Heavy Man, or adding mass and more messing around with top plates.

I'm a little frustrated tonight as the deck is still in a state of flux but it's next iteration is slowly coming to fruition. I'm in the process of refurbing and prepping a new heavier, stiffer top plate for my 2017 adventures with the Lenco. The marine resin has arrived today and shall at some stage be poured into the gaps on the underside of the top plate. I had to protect the mounting threads so a little bolt and some blutack will suffice and shall be removed when the marine resin has set.

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My old top plate is like a swiss cheese and has many holes which should really be filled up so tonight I've spent a little time deciding what needs to stay and what needs to be blocked up, as can be seen in these two pics. There won't be that much left when I've finished and these precautions should add a little more weight and stiffness to the top plate.

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The bearing is still being made so I can't progress any further with the deck. I'm just wanting to now get the deck together and do some long term listening so I can determine how it sounds and then start to improve it further with the next round of mods in 2017. I need to do some more experimenting with the NSC and I'm looking into the possibility of getting rid of the speed selector linkages. Right, I think that's as far as I can go, tomorrow might be the beginning of filling in the holes of the new top plate. As always....

[brian2957]

I'm a bit confused Andy . Where are you putting the resin ? Have you used this stuff before , got a link to it ?

I take it the Jolyon bearing hasn't arrived yet .

[Gazjam]

I'd always wanted to take the Lenco when I had mine down the PTP plate/ slate plinth route.

[Wakefield Turntables]

Brian,

the resin goes under the top plate around its perimeter it's supposed to stop resonance and add mass. I've never used the resin before but have used various similar products so I'm quite confident. The bearing hasn't arrived yet but he did say it would be beginning of December I'm just eager to get cracking.

[brian2957]

Cheers mate , I don't think I've come across this before . Can't this be done to the stock unit ? Or maybe fitting Dynamat or the like in this area .

[Wakefield Turntables]

Yeah you can do it to a stock unit no problems. Dynamat would work to dampen vibration and I've used it in the past but most people seem to say that it dampens the listening experience too much. Additionally there is no consensus of opinion as to where to best place the Dynamat. Boat resin is tried and tested and follows the well trodden path of adding mass to the top plate which is known to improve the '75s presentation, and it's probably easier to chip out than Dynamat if you don't like it. I should be posting some pix over the next few days.

[brian2957]

Thanks Andy , I'll be looking further into this .