LENCO - GL75 Project

[Wakefield Turntables]

Glad to see that you like the look of my two arm plinth Andy. It is sounding pretty good with my homemade unipivot arm and a Decca microscanner Gold cartridge. The 12" arms is still under construction and will have a Koetsu Red cartridge fitted which has just been rebuilt by Goldring.

I am curious as to how you intend to decouple the arm board.

The plinth is I believe one of Carls workshop build; I bought it second hand although unused. Excellent build quality and damned heavy.

Keith, glad to hear from you again! Sounds like you have a stunning deck and skills to match if your making your own tonearms, way out of my league! I've got a spare DECCA FFSS mk 2 sitting on my sideboard doing nothing so I may install it with a MKII at some point. And, funnily enough I have been thinking about getting Koetsu repaired (as it's not selling) and maybe using it on my Alphason. I love my M55E but it can easily be bettered. Decoupling the tonearm is pretty simple. I'm just going to have a tonearm pod made up which will inside the plinth but not actually attached in any way.

[Marra]

Keith, glad to hear from you again! Sounds like you have a stunning deck and skills to match if your making your own tonearms, way out of my league! I've got a spare DECCA FFSS mk 2 sitting on my sideboard doing nothing so I may install it with a MKII at some point. And, funnily enough I have been thinking about getting Koetsu repaired (as it's not selling) and maybe using it on my Alphason. I love my M55E but it can easily be bettered. Decoupling the tonearm is pretty simple. I'm just going to have a tonearm pod made up which will inside the plinth but not actually attached in any way.

Hi Andy; I've read good things re the Decca FFSS. Should be interesting. So the arm pod will slide into/through the plinth and sit on the shelf?

[Wakefield Turntables]

So the arm pod will slide into/through the plinth and sit on the shelf?

No because it would still be coupled. The idea is to have a shaft sunk through the whole thickness of the plinth and then simply house the arm pod in the shaft. The pod will have it's own feet. I could just have a smaller plinth and have the armpod sit externally but I like the look of a hulking big plinth with the tonearm pod neatly hidden inside. I would imagine it would be very hard for any motor vibration to get into the tonearm pod. Additionally the mass of the pod, direction and sinking of vbration into feet and then something like an ebony tonearm mount would certainly disrupt vibration transmission into the tonearm and cartridge. Of course I'm probably completely wrong with how all this works !

[Wakefield Turntables]

The Reference Lenco Pt LXXX - Lazarus!

The 75 is still alive and kicking and my passion for developing the deck has risen like Lazarus. I must admit to feeling a little apathetic towards the project over Winter, now the weather has improved I'm back in the garage messing around. I've sourced quite a bit of birch play for the new plinth. I'm not quite sure of the layout yet but that's probably something to start messing around with in the next few days. In the meantime I have decided that I'm going to experiment with a new birchplay tonearm mount for the Alphason. I don't have the correct drill bit so will have to buy something a little bit like these guys

drills.jpg

I need a 56mm diameter to mount Alphason. I've never been 100% with the tonearm's alignment or mounting and always thought that it could be improved upon. Ultimately the tonearm will be decouple on a heavy mass pod but I'd like to do a little experimentation to see if the various woods have any sonic impact on the deck. I'll start with birch ply and then make mounts from differing woods until I find something I like. My inspiration comes from the positive effects ebony had upon my 1210. I also hope to improve upon the alphason's alignment and setup and so improving the sonics. Wood will add additional mass to the tonearm mounting, currently I'm using EVA which whilst ok is not great and was only really meant as a stop gap. The next area of improvement is the slider used in mounting the idler wheel arm. The idler wheel arm is held in place with a two part mount which is very flimsy and also rattles. This is not good and consequently means that there are many surfaces with lots of moving parts all clatter and all this passes up into idler wheel and ultimately into the platter. NOT GOOD! This is a picture (FROM LENCO HEAVEN THANKS CHRIS1967) showing the old slider mount to the left of the picture. As you can see numerous parts. The solution is the large piece of aluminium to the right. I'm actually not happy with this design either as this had loads of nuts and washers which again means loads of surfaces to chatter and transmit vibration into the top plate and platter. My solution is to simply epoxy bond a single piece of aluminium onto the top plate and do away with all the nuts bolts and other components. Bonding the new slider mount needs to be precise due to the fact that its position controls the RPM of the platter. In an ideal world the top plate would have been milled from a solid piece of aluminium incorporating the idler arm mount. This would mean you loose two connecting surfaces merging into one but I suppose bonding with epoxy resin is about as good as I can get.

SLIDER6.jpg
SLIDER5.jpg

I'm not quite sure what to do with the idler wheel arm. I'm looking into ways to sink vibration from the idler wheel arm into the plinth or top plate, but then that's another update. Right you guys I'm signing off. Hope you like the update. As ever, stay tuned...

[brian2957]

Are we entering another phase of GL75 modifications Andy?

[Wakefield Turntables]

Are we entering another phase of GL75 modifications Andy?

Yep, but a lot of the mods are old ideas which I haven't yet implemented and then some are my own. The deck can't be pushed much further. I think it's now going to be about the deck and plinth interaction. Should be fun.

[brian2957]

Interesting ideas Andy . Yes I have a set of those hole cutters , they're not that expensive and IIRC 56mm is one of the standard sizes for the hole required for those little ceiling downlighters you see in people's homes .

While you're working on these mods , Is there any way you could shorten the idler wheel rod and resite the mounting ? . I think this would provide more stability to the sq if it could be done . I like your idea of fixing the idler mounting and removing all those nuts and bolts . Don't you use an electronic speed controller for the GL75 ? Wouldn't this give you some leeway regarding positioning of the idler wheel with regards to the motor shaft .

Look forward to the next episode Andy , just make sure you don't get snowed into your garage

[Wakefield Turntables]

Interesting ideas Andy . Yes I have a set of those hole cutters , they're not that expensive and IIRC 56mm is one of the standard sizes for the hole required for those little ceiling downlighters you see in people's homes .

While you're working on these mods , Is there any way you could shorten the idler wheel rod and resite the mounting ? . I think this would provide more stability to the sq if it could be done . I like your idea of fixing the idler mounting and removing all those nuts and bolts . Don't you use an electronic speed controller for the GL75 ? Wouldn't this give you some leeway regarding positioning of the idler wheel with regards to the motor shaft .

Look forward to the next episode Andy , just make sure you don't get snowed into your garage

I could shorten the idler wheel but to be honest there is a very specific mounting distance for the idler mounting that will produce 33.3rpm if your prepared to slide the thing up and down enough and then fix it into place. The speed controller does indeed help but this mod means you don't need one . Believe me or not it has actually snowed and now we are thawing out!

[brian2957]

Hah ! snow still to arrive up here

[Wakefield Turntables]

The Reference Lenco Pt LXXXI - Were off again!

The 75 has had a new raft of mods. All in these little bits and pieces took 3 hours to do. The drill bits arrive off e-bay and for £4 weren't too bad. A bit cheap and cheerful but got the job done. The first thing that I'd been planning for a while was a new tonearm mount. I'd originally produced one from EVA and whilst this worked well I always got the feeling that I needed something else. I quick rummage around the garage and I found some scrap 25mm plywood, 30 minutes later and i'd fabricated the tonearm mount. Not the best job in the world and I'll replace it for something better but still quite pleasing. Tonearm alignment is now much easier and the tonearm now truly sits parallel to the vinyl.

deck.jpg

I rebuilt the motor and remounted the motor whilst I had the chance. I also added additional dampening around the motor pillar mounts. The small rubber grommets have been added to try and keep the springs in place whilst also trying to dampening any vibration from the motor pillar mounts. Each of the three pillars recieved the same treatment. It's an old idea that some of the old Thoren's use, but they use a bit of sponge and this has been shown to impinge the springs and consequently affect there ability to reduce motor vibration.

motormount.jpg

The bearing stabiliser shaft also received additional rubber grommets. The idea is to reduce any bearing vibration getting into the plinth.

nut.jpg

The tonearm mounts also recieved some large rubber washer in a bid to further minimise vibration getting into the tonearm.

tonearmmount.jpg

I also added several small gromets to each of the plinth mounting bolts from the top plate. Sorry no picture.

Well how does it sound? Very very quite in between tracks. The tonearm isn't properly setup but I think that I might be onto a winner.

Stay tuned!