Ruby-unipivot

Ruby, My Dear!



Ruby was the second diy tonearm I’we built. The inspiration was Scheu  Tacco, but the resemblance is quite small. The
idea of Ruby was to experiment with uni-pivot technology, to see how hard is to build and tune one, and how it sounds. The materials used for construction were: wenge wood for the arm, aluminum for back side of the tonearm, brass+ teflon insulation for the counterweight, and a ruby watch bearing. The bearing scheme is a non-inverted one: the ruby jewel is supported by the tonearm while the steel axle is hosted by the arm-wand pillow support.
There is no anti-skating system on Ruby tonearm: this role is played by the tonearm wires elasticity. It’s dumb
simple, but painstaking to set-up properly! At least it works.I tried wire&rope method too, but was hard to implement on this particular unipivot tonearm: antiskating force should be applied at the same level with the bearing, which in our case was not possible.For the internal wire I was using a screened wire from an old tonearm, with decent results.


The Sound
Ruby sounded great, despite was finiky to set-up. I was using the Van Den Hull DDT II MC cartidge with marvelous
results. The bass was tight and fast, very clean and deep enough to make a good base for all kind of music programme.
Medium was as should be, vibrant and still precize, with enough warmth on voices.The highs were natural whitout being smeared or harsh, and the soundstage was awesome wide and layered in depth on carefully mastered LP’s.
Compared to a ball-bearing type of tonearm (Dual, Project), the sound of my Ruby arm was faster (with good attack )
more airy, generating a very wide soundstage and with a more natural presentation on upper-medium and highs tones. Timbral presentation is accurate, but this is one of the strenghts of the Vand den Hull cartridges as well :)
At my old Dual tonearm, very well made in therms of parts and craftmanship, the bass was a bit deeper but muddier,
less precise.
After all, Ruby was a nice project to work at, not very hard to accomplish and with outstanding results. Mated with
a good mc cartrige, should be the first choice of a serious diy tonearm on your way from MM to MC world!

find me:
grid (at ) attitube (dot com)
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