Custom plinth/box for ROK...

Todd MacDona said:

I see lots of faces in the burl. It would freak my kids out no doubt.

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TT Rorschach test! Kinda looks Mayan or Inca? Can't remember who had the block hats in their hieroglyphs.

MRL_Audio said:

Got any photo's of it? Love to see it.

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First off I will never admit to being very good with wood and don't have any carpentry tools, other than I used a table saw, and some clamps and glue, and I do have an old router that I purchased at a thrift store. I purchased the veneer off ebay and used contact cement as I simply wanted to get the table up, pretty much built it and playing in two days. I used a water base clear coat on the veneer same stuff I used on some hard wood flooring, dries quick and I was told harder finish than that of petroleum based varnishes. Hey I even matched the grain! I really didn't know what to expect out of these old tables, and didn't think they were anything in the magnitude of a Garrard so I wanted to keep it simple and cost effective. In retrospect some day I will probably get a good arm and build another plinth and now that I can use this I can take my time on a better one. I can't say I am disappointed in the performance of the table, I don't find it noisy at all, and on my old mono micro grooves it sound pretty good.

I should add I really enjoyed doing it but it is a bit frustrating not having access to a real wood shop, with all the right tools, and really working with wood seems like something that you need to take your time with and not get in a hurry.

I really like the veneer the OP picked out, it takes burl to another level.:thmbsp:

Joe Roberts said:

Beautiful work, AA! Now you can start on mine.

I just posted a thread about improving resonant box plinths rather than tagging it on here.

http://www.audiokarma.org/forums/showthread.php?p=9061139#post9061139

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Joe,
You want one? PM me and let's talk. I also did find that pair of 802Ds...

That's a beautiful job. Congratulations to both of you.

That ROK arm is in pretty good visual shape and with a little TLC, cleaning, lubing, adjusting, and a low compliance vintage cartridge or a new MC and surprising magic may very well begin.

beatcomber said:

Seriously, analog addict, you and your client might want to reconsider this. I moved my ROK L-34 from a box plinth to a massive layered one, and the difference in performance was not minor (although it weighs a ton!). It could still be veneered to look pretty.

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I hope your expensive, heavy turntable is not sitting on what looks like a $4.99 plastic wobbly thrift store stand!

George W said:

I hope your expensive, heavy turntable is not sitting on what looks like a $4.99 plastic wobbly thrift store stand!

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I think that's an Ikea side table (made of layers of particle board and cardboard).

mfrench said:

Two inside jobs:
I did a Lenco for a friend by creating a "butcher block"-like pattern on the inside of a stock L75 plinth, and also included some remnant soapstone for mass, and, for another CLD layer. It worked out really well.
I also buit a massive theory plinth within an old phonograph cabinet; and utilized isolating points to keep the turntable from feeding back with the onboard speaker. It worked.

With this said ^^, this plinth build is looking really nice.

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So you built up the stock plinth on the inside? I've been thinking of doing something similar with the huge open box on my R-O-K B12-H as a relatively simple starting point. The open box is definitely a very good resonator.

Progress

fiddlefye said:

So you built up the stock plinth on the inside? I've been thinking of doing something similar with the huge open box on my R-O-K B12-H as a relatively simple starting point. The open box is definitely a very good resonator.

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Hi Bruce,

I'm sorry, but I missed this post until just this morning.

I bought this deck off eBay, from a guy that lived in the San Francisco area, assuming that it was a 60hz model. It just came up as a BIN offering, and far below what most L75 go for.
It turns out that he was from S. Africa, and it was a 50hz model, which explains the price.
I had an extra 60hz motor, so I converted it to a 60hz deck. A friend wanted to buy it from me. He does't play records all that often, but, still has his collection "from back in the day".
So I told him that I'd convert it to the 60hz model, and fix it up for him.
It had a really nice veneer over real plywood base; most have veneer over some form of fiberboard base; so this was a really nice base, and clean, without external damage.
So i had some scrap maple 1x2 trim left over from some finishing jobs. I started cutting and fitting it around the internal areas of base. I used wood glue and clamps to attach the layers. I filled in with the layers to a point where the TT mechanical works would no longer have been accessible if I'd continued it.
The final two layers were of soapstone from my soapstone plinth building projects, to change the mass and density of the bracing, as a form of CLD layer.

The underside of an L75 base:

The original base had a cheap fingerboard enclosing panel, that was about 1/8" thick, and flimsy.

Opened up:

I placed the internal bracing around the suspension/top plate mounting screws, so that the top plate could be a accessed and removed if necessary. You can see those mounting points.

Internal bracing:

To this layering of bracing, I added as a final layer, two pieces of remnant soapstone, cut to match the 1x2 maple bracing (the remnant soapstone is 1.25” thick), to change the density of the added wood; as a form of CLD layer. I neglected to take pics of the added soapstone layer. It was installed in the same fashion that you see the wood “slats”, and was screwed to the wood as the outer most layer.
I did this bracing layering up to a point where there were underhung items that precluded going any further with it.

I then added an 18mm/.70” base added, instead of the 1/8” fiberboard panel. I cut a vent hole for the motor, and covered it with expanded metal screen to prevent fingers from getting shocked:


I also added some T-Nuts and adjustable legs with rubber feet (also not shown)
This new birch ply base plate made a huge difference in firming up the original base.

Added a pair of RCA jacks, and ground post:

Corner braces



fitment recheck



edge veneer placement



Wasn't able to glue the edge veneer because we couldn't find the veneer tape. Will buy some tomorrow...

Looking to be an impressive unit.

Front view



Back view, along with the strip cut off the bottom to produce the final depth and trim the rough finished bottom edge. I put some Watco Natural on the strip to get a better idea of the final color.

dtut said:

That's a beautiful job. Congratulations to both of you.

That ROK arm is in pretty good visual shape and with a little TLC, cleaning, lubing, adjusting, and a low compliance vintage cartridge or a new MC and surprising magic may very well begin.

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ROK arms can be excellent with the right cartridge. I have a mono-wired ROK Model 160 transcription arm with a GE VRII, and it sounds spectacular with old mono records.

Here's the veneer with a little watco natural....

It will be real fun to watch that burl pop with layers of finish. So what's the plan with the finish?

Watco Natural for the finish. First coat going on here. Wet sand with 400 grit paper tomorrow and then another coat.

That veneer looks gorgeous. Nice job. :thmbsp:

wet sand with the oil , it makes great fill and will push it deep into the grain.. nice work