Alpair 12P MLTLs - Day 8

Day 8 - 3 hours

Time to cut out the absorbent material and glue it in both cabinets. It's starting to feel like I'm getting somewhere now.

First, of course, temperature watch. Even I'm getting bored of this now. Anyway 9 degrees today.

Here's both cabs together after the cramps were stripped from the second.

The absorbent is old fashioned carpet underlay, roughly 10mm thick. It's not so easy to get these days, fortunately Dave the Bass had some spare he let me have. Thanks Dave :-). The top, back and one side is lined; here it's cut to size and trial fit.

I used some spray adhesive to mount the material. I was a little unsure what to use, some of the cans sounded like the bond might be a bit temporary or light, and I don't want the linings to come loose in the future. So I used a contact type adhesive, sprayed on to the cabinet and a couple of coats on the material. It comes out as a web and the fibrous nature of the lining meant it webbed up almost immediately without really making contact with the body of the material. On the other hand I found it difficult to get an even coverage on the plywood. I think it might have made quite a mess if I was trying to glue laminate, but it's good enough for this job.

Once the coats had dried so they were no longer tacky (the can says 2 to 5 minutes but it took more like 10 due to the low temperature) the pieces were placed carefully. As it's a contact adhesive it tends to grab as soon as it touches each other so steady and careful positioning was required. Then pressure was applied to ensure the two substrates made good contact. And that's it. Hopefully.

All done.

And here are the two cabinets together.

One last job for today, glue on the side of one of the cabinets. A little more time today to get a photo as there's a lot less glueing for just a side.

And here it is cramped up.

That's it for today, no more cramps.

Alpair 12P MLTLs - Day 7

Day 7 - 1 hour

Dad was round again yesterday so as well as clearing leaves from the gutters it was important I got the other cabinet glued up - it's always easier glueing with two!

First temperature watch, a little cool for glueing really, barely 5 degrees

Here's the first cab we glued last week now stripped of the cramps. Not bad, but there's a very slight bow in the front baffle. Either there's a slight bow in the bench or the composite of the ply and mdf has expanded or contracted at slightly different rates in the year it's been sat in the garage on the bench subject to the natural moisture in the air. This wouldn't have been a problem if I'd realised when glueing up, but I missed it and the side is a little "short" in centre of the baffle. It shouldn't be a problem as I think I'll have to make a cover for the baffle as the greeny grey look of the 12Ps hasn't gone down too well...

And here's the second cabinet glued up. Note the damp wood where the glue that's been squeezed out has been wiped off. Best not to get the wood unduly wet as it lifts the grain. Light sanding should fettle this.

And that's it for another day.

Alpair 12P MLTLs - Day 6

Day 6 - 1 hour

It's nearly a year since I last made any progress with these speakers. It's been a very busy time in the garden this year making trellis fences, gates, arches and a shed from scratch. But now it's winter it's audio time again!

After a long overdue tidy up in the garage I could see the bench again so I could finally start to glue up the first speaker. But first, temperature watch. It was a particularly mild and pleasant morning - 14 degrees in the still of the low slanting sun.

Not too much to talk about but here's a photo of the first gluing up. You can never have too many cramps. One side is left off as three of the internal faces are to be lined with absorbency material. Still a fair bit to do.

Lenco L75 Replinth

Goodness, 8 months since my last blog. The Google servers must have thought I'd given up. Life just gets in the way sometimes. And even this isn't a blog about something I've done, it's about a rather special plinth that Anthony Cresswell made for my Lenco L75. And here it is, playing REM's New Adventures in Hi Fi, rather appropriate but completely unintentional.

I've had a Goldring Lenco for a few years waiting for the right moment to be redeveloped. I'd been leaning towards a solid replacement plinth, either slate or constrained layer damped with various timber sheet materials, which would do away with the slightly tinny top plate. Something along the lines of Pieter's Top Plate looks to have some merit in its approach to me.

So I was starting to do a little more detailed research about the Lenco itself and how it would need taking apart, chopping down and rebuilding when Ant posted on the Audio Talk forum that he'd just done something very similar. Given my somewhat glacial timescale for audio projects commissioning Ant seemed a pragmatic choice. Besides, he knows what he's doing and I knew he'd make a much better job than I would...

The Lenco is an idler drive turntable - it doesn't use a soft belt around the rim of the platter, and doesn't drive the spindle directly. It's a mechanically sophisticated method of spinning the platter, but can be affected by poor setup, just like any turntable.

Unlike Garrards, like a 301 or 401, which drive the inside of the platter rim with a horizontal idler wheel, the Lenco uses a vertical idler wheel which drives the underside of the platter top. Idler drive proponents will discuss at length pros and cons of different drive systems, the quality of the motors, and even whether a grease bearing 301 is better than one with an oil bearing. I'll leave that discussion to others with more time and inclination, but those that have taken these things apart are impressed with the build quality - they're Swiss and the build quality shows.

Here are a series of photos that Ant took during the build, for which I'm very grateful. The first is when Ant had initially stripped the deck down. It's nearly as old as I am and cosmetically in excellent shape, much better than me. In a way it was a shame it was going under the angle grinder, but some things have to be done.

No going back now...

I think this is something akin to the PTP mod mentioned earlier (with apologies to Pieter if it isn't!)

And now with the idler wheel, spindle and linkages refitted.

Next job was the plinth with lots of routing of a sandwich of a number of layers of mdf and plywood. The theory of constrained layer damping (CLD) is that a different layer of material is used between others materials to damp vibration that the outer materials can't. Rubber is often used, but as we know, audio is a mysterious beast with many different ways to succeed.

Here we can see the differing cutouts in each layer - just enough is removed to house the mechanism, this way the mass is maintained.

Those with a keen eye that know their Lencos will have noted that Ant has been rather clever in the way he's mounted the mechanics. One of the biggest drawbacks with the L75 for me is that the on/off lever is located virtually under the cartridge. I can't imagine how many styluses have been destroyed by unfortunate accident over the years. So Ant reoriented the mechanism with the on/off lever at the back - this is a compromise as it doesn't want to be too close to the arm collar either. This puts the variable speed lever at the front, and the idler wheel at the opposite side of the platter from the arm, which is probably a good thing.

And here it is with my old Linn Ekos mounted. I'd wanted to try an Audiomods arm but Ant suggested trying the Ekos - it has a very slightly different effective length than the Rega-derived Audiomods so will need an arm board should I change in the future, but using the Ekos was a "zero cost option", additional cost anyway, as it was sat on a shelf unused. And for that matter I had a Kontrapunkt b with low hours also sat in a box, so why not use that too.

Next job was sanding. Lots and lots of sanding, after the plinth was cut roughly to shape.

Next was paint time, starting with the underside.

Just 5 coats of black on the rim. It does look good I have to say.

It turns out the mechanics weren't quite as good as thought. Somehow it had seized "on" - even though the platter wasn't turning the motor was turning. Must have been like this for some time before I obtained it. Previously I'd only listened to about a side of one record - I'd lashed up an old Linn K18 just to try it and was surprised by just how "together" it sounded. Enough to know a full rebuild was worthwhile ;-). So at least I didn't make it any worse. So Ant stripped it down, which saved me a job.

Note the pit the spindle has worn in the bottom plate. Ant simply turned the plate over. Testament to the Swiss build quality really.

Back to the plinth, and it was veneer time - a simple English oak. It's difficult to see but Ant managed to salvage the original Lenco sticker for provenance - it's located on the left hand side of the remaining part of the platter.

And here it is with a couple of coats of danish oil (I think)

And finally at home with the the Kontra b fitted, this time playing the Living Stereo release of Reiner's Chicago Philharmonic performance of Pictures at an Exhibition.

I must say I'm very pleased with how it's turned out. I'm always a little reluctant to wax lyrical as one day I'll probably look back and think I was talking rubbish, and well, we've all read those oh-so fawning reviews that mean nothing.

But Ant's done a terrific job, much better than I would. It strikes an excellent compromise - it has the drive of an idler (obviously), and the effortlessness of a good direct drive. Compared to my 401 in twin deck slate plinth with 12" ebony Schroeder-a-like arm and Denon 103pro cartridge this has the edge. The bass is firm and controlled, and better balanced than the 401 I think, which tends to tank-on. Coupled with the fluid mid that reminds me of direct drive this is an excellent turntable.

One day I should try an alternative arm and cartridge as I've never been a huge fan of the Kontra b - at least the 103pro should get a run out. That might squeeze a little more musicality out, but for now I'm very happy with it as it is.

I should add that I have no connection with Ant other than as an audio friend through Audio Talk. We live about half an hour away which makes it easier too. But I have no financial interest. With that said, make no mistake - in the crazy world of audio, if you were to find yourself a half decent Lenco (cosmetics aren't important) and get Ant to build you a plinth you'd have a killer turntable for pretty cheap. Ant has a website where you can read his own thoughts. Cheers Ant.