300 mm pivot to spindle: what size arm?
- Thread starter Tonoje
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Thanks. For this plinth, I'd either have to make a new armboard to use with the arm I've got now, or buy a new arm. As the plinth isn't wood, and I'm no machinist, I'd prefer the second option, which is to find an arm that will fit the solid hunk of metal that they used for the armboard. I'm not sure what arm it was originally likely to have been made for, but from what you say, it sounds like a 12" arm is what I should be looking at. This is for a Technics SP10. I've never had to find an arm for a plinth before, and I know little about the geometry calculations. In cruder terms, with the armboard mounted, the armhole is at about a 2 o'clock angle from the spindle, and an installed arm would be over at the right edge armboard/plinth. The closest point at the right edge of the arm base to the right edge of the plinth is less than 1 cm. At the rear edge of the plinth, there is about 3.5 cm separation between the arm base and the edge. The stub of the current tonearm protrudes slightly beyond the rear edge of the plinth, though I don't plan to use a dust cover anyway, so that wouldn't matter.
tabarddn51
Super Member
Hi, well as you have a SP10, then you need a descent arm. What cart did you intend to use.
It's (the cart) compliance will dictate what type of arm, low, med, high you will need.
Cheers
It's (the cart) compliance will dictate what type of arm, low, med, high you will need.
Cheers
tabarddn51
Super Member
Hi, They have a reasonably low compliance of 10 in Japanese spec, read 14 Euro spec. So the arm will need to be medium to medium heavy to be a good match & get your arm/carts resonant frequency in the right place.
So the lowest cost new 12'' arm I know of is a Temaad 12'' Kit arm (simple assembly) at US$340 and then you can go all the way to a Brinckman, depending on your budget.
Cheers
So the lowest cost new 12'' arm I know of is a Temaad 12'' Kit arm (simple assembly) at US$340 and then you can go all the way to a Brinckman, depending on your budget.
Cheers
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Is the armboard removable? Rather than letting the tail wag the dog - finding an arm that works with the board - it might make sense to replace the board, and with something easier to drill. To the degree that armboards are factors in the way a table sounds, steel may be a mixed blessing. Certainly it will be rigid, but it also may be resonant. Wood, or plywood, may be slightly less rigid, but it is usually more damped.
Not knowing the turntable, plinth, or board, it is hard to be more certain about whether you have such an unusually excellent set up that it would be worth spending the large sums needed to get a good 12 inch arm, or whether you would be much better served swapping the board out.
Not knowing the turntable, plinth, or board, it is hard to be more certain about whether you have such an unusually excellent set up that it would be worth spending the large sums needed to get a good 12 inch arm, or whether you would be much better served swapping the board out.
setup1
Super Member
FWIW, my Stax UA-3NL and it's later iteration, the UA-70, pivot to spindle mounting distance = 300 mm
Very interesting option. In particular, I hadn't realized that 12" inch arms were so costly, but all the Japanese ones I've seen so far are well beyond my budget, where shorter arms from the same maker are pretty affordable.
It is. Actually, I thought that's what armboards do.
The turntable is a Technics SP10 Mk II.
The plinth is by Resinamic Sound, whoever they were. They seem to have made plinths for various turntable models, including Technics and Sony.
At a guess, the plinth chassis is cast (edit: well, perhaps not - possibly stamped. I'll go with "formed", as I know little about these processes) maybe of aluminium, and uses some kind of filler material. The sandwich is visible in the walls of the turntable cutout.
I originally thought a longer arm would be affordable from the Japan brands I had in mind, but it doesn't look that way. So now the choices are probably to find something within budget, like the kit mentioned by tabbarddn51, or make a board myself for the arm I already have. That was under consideration when I bought the plinth anyway, and instead of excellence, good will do for the time being.
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There is a somewhat affordable long arm from one of the Baltic States - it is wood with brass and various other metal parts. A friend has one and likes how it sounds. I don't know the name but if you look for long arms on ebay it shows up.
Drilling aluminum isn't that hard if especially if you have a drill press. You could cover up the existing hole (or simply ignore it) and drill a more useful one, or get a local machine shop to do it. It's a pretty trivial task, so I doubt it would cost much.
Drilling aluminum isn't that hard if especially if you have a drill press. You could cover up the existing hole (or simply ignore it) and drill a more useful one, or get a local machine shop to do it. It's a pretty trivial task, so I doubt it would cost much.
have one on my Russco Studio Pro