What's new

Oliver Acoustic Research AR-94 specifications
Daniel Azziorri RCA new topic
Roy A. Esposito Acoustat topic reply
Joe Kasperowski Acoustat topic reply
Ed Optimus topic reply

I get the Bogen

Ok, so I saw this thread on AudiogoN while browsing, surfing, what have you, one night last winter; it seemed neat, but at that time, I was

  1. finishing a pair of Gainclones;
  2. tweaking my listening room/lair;
  3. refining my recently-completed BuschHorns;
  4. fixating on a VPI Scout;
  5. in the middle of a huge backyard project;

so I wasn't moved to immediate action, but I *did* file it away for later reference.

Skip forward to late May 2004 - I don't remember now, but for some reason, I had been looking at the Garrard 301s/401s (I had already given up on owning a Thorens 124, but I never stopped wanting one). I had always liked the Rek-O-Kuts, but like many impressionable audiophiles, dismissed them out-of-hand as being too noisy, rumbly, clunky, etc., despite the fact that MANY audiophiles in the 50's used them, at a time when this was really a hobby that involved careful study and consideration of components, enclosures, etc.

So I saw, somewhere, a reference to the AudiogoN thread John Nantais started, about taking these Swiss monsters and taming them with a suitably massive plinth/base and modern arm. Maybe more than anything else, because It Sounded Cool, and just contrarian enough to interest me, I began weeks of reading about these, and then a "Bogen" appeared on eBay, at a very attractive price, so I jumped the gun and bid on it.

I was the only bidder; which may have been a good thing, since I can see myself having gone to the wire for this one, but I only wound up having to pay $75, including shipping from NY state. The auction went very well, and the seller packed it quite well, too - so well that even UPS did minimal damage when they apparently let this one drop on its side; the only permanent effect was to shear the mounting bolts - no problem, since those would be replaced anyway, but I breathed a sigh of relief that the mechanicals survived with NO damage. For what its worth, I also own a Rega, 2 ARs & a Thorens, as well as various Technics, Philips, and even a BIC table, and I certainly don't think any of them would have fared as well - that was when I realized I might be in love...

Once I determined the parts all seemed to be there, and had at least a token film of lube, I plugged it in and it started right up. There was some noise, but not much, and not the bad, squealing, about-to-start-smoking kind of noise, so I brought the 'table downstairs, disassembled it, and started the gentle refurb: cleaning and re-lubing the motor, greasing the speed-change works, etc. - there wasn't much to do here - this TT seems to have had a very good life in upstate NY, and the whole thing took about an hour, mainly because I moved very carefully, working with about 9 www printouts arrayed in front of me for reference. I put it back in the original plinth, and BAM! - sweet & silent- quieter than my AR (which is not definitive, but quite good, nonetheless).

Original Bogen-PrestoLenco

Advertisement

I build a plinth

The heart of this project is the high-mass plinth to damp (or absorb, or drain,or dissipate, depending on who you read) the rumble ostensibly produced bythe Mighty Lenco Motor™.

My plinth, being built on a frayed & tatty shoestring, isn't as massive as those of John Nantais or "willbewill" (which are several inches' worth of MDF) - mine is a mere 4", composed of six alternating layers of a 1/2" plywood and 3/4" underlayment (Georgia-Pacific high-quality underlayment, which is used to deaden floors before the decorative/final flooring is laid) - all held together with thick layers of VERY slow-curing hide glue to allow for last-minute layer arrangement, alignment, etc. An unexpected result of using the hide glue is that because it has been rainy and warm here lately, it's taken even longer than normal to cure, which has given the plinth additional strength, rigidity, and damping (I hope - maybe it's just taken a long time, and I'm rationalizing).

The Bogen arrived on what appeared to be an "original" plinth, so I snapped the top layer off the old plinth and traced the outline onto the sheets of plywood & underlayment . I used my trusty table saw to get all the plinth layers to nearly the same size (within 1/8") - 19" X 21", which left much more room around the edges of the plinth - a great place for stowing the brushes and other little tools that one needs to run an analog system. I cut the excess out with a jigsaw - the cutting bit for my router was too shallow for my tastes, but if I do this again, I *will* get a deeper bit and build a jig to get really clean cuts, and take less time. The original cutouts left plenty of room for the original arm & cueing lever, which I will not use, so that empty volume will get some type of filler - maybe just some MDF blocks glued together, then glued to the main assembly; maybe something else, but I want to fill it in as much as possible, with as much mass as I can - of course, I'll have to leave some room for the *new* tonearm wires, pivot bearing, etc., so that's a bit down on the list, near the "Eventually, When I Feel Like It" section.

Attaching the deck to the plinth has been tricky - the local shops (i.e., in my neighborhood: Lowe's, Ace Hardware, Home Depot(!), and the "Old Man Hardware Store" - General Hardware on Peachtree Road, in Brookhaven) don't stock a wide variety of metric bolts, let alone ~10 cm/~100mm - .4/.7 metric bolts, so I've had to try and source them elsewhere, OR improvise something to secure them all the way through the plinth. I purposely over-sized the mounting holes for the bolts, with the idea of adding something (plaster, small lead shot, etc.) to add more mass around the bolt-foot-plinth connection than I lost in the wood removed from drilling.

For feet, I have a set of adjustable brass cones from PartsExpress - $17 for four, and they even have adhesive-backed foam tape to attach them to the component, as well as discs to receive the points and protect the furniture where they rest (note: they SUCK on cheap, light DVD players). I am still debating whether to connect these (somehow) to the mounting bolts, or to dispense with the cones altogether and use acorn nuts as feet, essentially attached to the deck itself - this is how John N. originally described the construction, but, as a friend says, "We'll see ...."

I haven't finished the plinth yet - I'm mainly thinking of deep, rich, saturated red, maybe with some nice hardwood trim (but NOT cocobolo or bubinga or purpleheart; my father-in-law has a stock of nice 200-year-old walnut that came from a tobbaco barn on his family farm, and I've got some of that ... it would match nicelywith the end-pieces of my GainClones)

Raw plinth

I add a tonearm

As mentioned elsewhere, I already have a P2, with the RB250 - this is effectively the default tonearm in 2004, so I figured I should use it (which is why I went with the P2 to begin with: re-usability of its constituent parts; I'm also doing another DIY project with the spindle bearing and platter, but that's another story ... anyone want to buy a perfect Rega P2 plinth? - new motorassembly, *perfect* dustcover, and shipping box included ....).

I also am DYING to try a Decca International (probably will order one soon, before the dollar bottoms out against the Euro); I've also started designing and working on a DIY unipivot, inspired by the Altmann DIY tonearm, but that is also more of an, "Eventually, When I Feel More Like It" item on my to-do list.

Other builders have stated that the Rega "drops in" to the stock tonearm mounting hole, but mine didn't - since this was a Bogen/Presto rebadged Lenco, maybe it was shipped with a different arm assembly, and thus used slightly different mounting dimensions. At any rate, I needed to move the arm forward to get the "optimal" mounting geometry, so I ground away a bit of the adamantium that composes the deck. Really - this metal even defied a tungsten carbide cutting bit in a high-speed hammer drill; the only way I could get it removed was to cut very small, shallow slots with a saw, then grind those down. Luckily, it didn't take long once I hit on this method, and I was able to lengthen it just enough to acommodate either "official" pivot-spindle mounting distance (219.5 vs 222 mm). In order to secure the stock Rega mounting nut, and to stiffen up the arm-deck interface, I added a 3/16" walnut mini-armboard (or maxi-washer) underneath the deck, and now even heavy taps on the deck don't make it to the arm (as far as I can tell). I did have to add some spacers betweenthe cartridge and the mount to raise VTA, but with a taller cartridge (I'm using my "tester," a Grado Red) or thicker mat (I'm using the stock mat, rubber-cemented to ther platter), they may need to come out; a somewhat shorter/lower cartridge may be just barely workable.

detail of cutout for Rega arm

Tone arm mounted

I listen

Here are the early, just-finished-and-it's-late photos - sorry for the download time - I'll optimize and comment on these soon!

The Bogen with the old cover - it fits nicely, and looks pretty good, too - no plans to replace this one anytime soon.

Coverless - nice & clean; the red is as close a match as I could find to the reds used on some Loewy-designed Fairchild amps of the era ...

I even used the original spacers to approximate the VTA on this Grado Red; hope they work with the V15 ... PS Yes, it does look like the cartridge is twisted, but that's an artifact of the photo; it passes the HFNNR azimuth tests fine ...

Detail of the motor