advertisement


Sideways Uni-Pivot Arm, SUPATRAC Blackbird, formerly "Ekos Killer (Price?)"

I recently had my Ekos serviced by Johnny Audiorigami.
I had arranged for a rewire an inspection report & remedy any issues he felt were required. The arm is knocking on 30 yrs old, so I wouldn’t have been shocked to hear some extra work was needed.
But no, pretty much a clean bill of health. Bearings, springs, cue lift all spot on, no remedial work required.
So this proves to me two things...........
1 that the Ekos is a bloomin’ well made, high quality arm, &
2 Johnny is a top fella to deal with. Excellent standard of work on the rewire & bags of honesty in his work ethic. Superb stuff.
 
It reminds me a bit of the Well Tempered tonearm...
...I wonder if it shares a similar sound signature. My guess is that the Well Tempered would sound more damped in comparison as the silicon not only resists the stylus drag but would help absorb any energy from the cartridge itself. The spike could possibly make for a more dynamic sound...

Yes, I designed this arm partly in response to what I think may be lacking in the Well Tempered arms. I have an Amadeus, which I love, but in a direct comparison with a Klimax Sondek I noticed a marginal shortfall in detail and 'punch' and began to consider why. I conjectured that energy absorbed is energy lost. I designed this arm with a more edge-of-seat performance as a goal, and it works. Unlike WT I have striven for maximum rigidity, very low effective mass and zero wow. I don't think there is much similarity in sound - Supatrac is an altogether different beast.

Firebaugh, though, is an inspirational genius.
 
I've always been a bit suspicious of silicon fluid damping for this same reason but can see the benefits in some applications. I think the horizontal spike is really novel and appears to be doing just what you hoped based on your initial findings. I would guess that as soon as the stylus hits the run-in groove this immediately loads the horizontal bearing and makes everything pretty rigid. Since spikes couple, there is an energy transfer route down the pillar. I wonder if there would be any significant difference if the spike direction was changed? If it were part of the counterweight assembly pointing in the direction of the pillar would that make any audible difference?

Look forward to following developments - it's always good to see a fresh approach so wishing you every success with it.
 
I've always been a bit suspicious of silicon fluid damping for this same reason but can see the benefits in some applications. I think the horizontal spike is really novel and appears to be doing just what you hoped based on your initial findings. I would guess that as soon as the stylus hits the run-in groove this immediately loads the horizontal bearing and makes everything pretty rigid. Since spikes couple, there is an energy transfer route down the pillar. I wonder if there would be any significant difference if the spike direction was changed? If it were part of the counterweight assembly pointing in the direction of the pillar would that make any audible difference?

Look forward to following developments - it's always good to see a fresh approach so wishing you every success with it.

Thank you - very kind. I included in my patent application a version with the spike/thrust-plate reversed as you describe. I suspect it makes little difference and have not bothered to prototype that configuration. If you're going to adjust or replace the spike it's easier when it's attached to the turntable rather than the less stable arm.

Your observation that stylus drag loads the bearing is exactly right. Stylus drag varies with signal strength, but it is always positively in the roughly same direction, whereas gravity remains constant. Hopefully.

As regards silicon fluid, yes, my guess is that it significantly increases effective mass as seen by the cantilever suspension, through viscous friction. If you have played with a Well Tempered arm then you will know that while it rotates nicely in yaw and pitch axes, there is a certain smooth frictional effect if you try to swing the arm rapidly. Whether that's a good or bad thing, I can't say, but my intention was to avoid it, and produce a more responsive arm in terms of warp-riding, at least.
 
Prototype 0.1.4, a chrome bumper homage.

iv.black.jpg
 
As a collection of parts it still looks a little ‘industrial’. I think once assembled and on a deck it may look altogether more purposeful. It’s never going to be pretty but I for one could easily live with that if it delivers on sound.
 


advertisement


Back
Top