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

Today I installed Supatrac Blackbird s/n 1 on my customer's Technics SL1000R in the 12.5 inch (left-hand) armboard.

In my entirely objective ;-) opinion it sounds more than a match for the Technics TXQ0031 magnesium gimbal bearing arm (https://www.hardtofindhifi.com/technics-sl-1000rt-1) which is mounted in the right-hand arm board.

The Blackbird may have been at a slight disadvantage since we started listening before accurate cartridge alignment, and with a heavily worn My Sonic Lab Eminent, and we were so caught up in listening that we did not adjust.

Both arms/cartridges sounded a bit edgy and rough at first, but once the Soulution monoblocs warmed up, it became enjoyable. The difference between the two arms was not huge. I noticed that the sound stage was larger on the Supatrac, which is not always a good sign, but in fact I thought that ambience and atmosphere felt slightly more realistic, and all instruments were punchy, dynamic with very high resolution of details.

I'll say more about my impressions later, but my customer and I agreed that Supatrac did a better job of revealing every bass note in Bob Dylan's Shelter whereas some of them were getting a bit lost with the default arm. My customer described the Technics arm as a bit 'thin' in comparison, and I would put that down to the Supatrac sounding richer in mid and bass tones, so Dylan's slightly abrasive voice was more complex and throaty, less exclusively nasal.

I say all this with the proviso that the cartridges were different and so not a level playing field, so take this impression at the price you paid for it. The cartridge on the Technics was a beautiful-looking new moving coil with a Japanese name which I can't quite recall but will find out. I have examined the older Eminent under a microscope and I thought I saw signs of extensive worn flats in the speculative reflections of bright lights off the stylus contact areas. I've suggested it goes for retipping.

I'm looking forward to listening again once the Blackbird's kevlar suspension threads have settled in, and I will keep you posted. I will also try to find time to take some pictures on my next visit.

Please don't hesitate to ask any questions you may have.
 
Vinny said:
Be careful in judging wear from the prescence of flats, unless you are very familiar with any particular stylus type/shape. Some have flats from new.

Advanced Stylus Shapes: Pics, discussion, patents.- Vinyl Engine
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Yes, this is an interesting issue. I try to use the specular reflection of a bright light off the contact area at the very tip.

Generally with a newish line-contact profile, if you orient the cartridge correctly you can roll it in the groove axis and see the reflective line as it moves round under the stylus. With a worn stylus I think the reflection can suddenly change as you roll it, the line shape is broken, much fatter, or almost looks like a line at right angles to the expected direction, in other words it changes from running at nearly a right angle to the cantilever, to running nearly parallel with the cantilever. This is a miniscule feature of the very tip of the diamond so it takes care to examine it carefully and not form the wrong conclusion.

I am open minded as to what constitutes 'worn' and how much record damage is done at what stage, but I do think that the sound of a cartridge can be absolutely transformed by a good new diamond.
 
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@sonddek I've been thinking about your lifting string arrangement, and wonder if two holes are drilled, the string could become a loop? This could then satisfy a range of lifting techniques, including your plucking action, finger through the loop, etc, and would also provide a pair of holes for a conventional type lift.
You may have already considered and discounted the idea, just trying to help.
 
trick cyclist said:
@sonddek I've been thinking about your lifting string arrangement, and wonder if two holes are drilled, the string could become a loop? This could then satisfy a range of lifting techniques, including your plucking action, finger through the loop, etc, and would also provide a pair of holes for a conventional type lift.
You may have already considered and discounted the idea, just trying to help.
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Interesting idea - I will give it some thought. My first thought is that a loop might increase the fumble rate as it limits the angles which you can pinch. I think only one hole is needed for the stiff lift. The arm is light enough so I'm inclined to drill as few holes as absolutely necessary.

I'm going to make a video demonstrating use of the string-lift as I think it will clear up a few misconceptions. I'll also post pictures of the stiff handle.
 
One thing that might put off some prospective customers is that this is the first iteration of a product that utilises a new idea and that means it is highly likely that a second, improved iteration will be forthcoming in the relatively near future (assuming the first iteration enjoys reasonable success). Some prospective buyers may therefore decide to defer their purchase and wait for the improved “Gen 2” arm. To counteract this might I suggest you promise a very generous trade up (part exchange) deal against any such Gen 2 arm to anyone buying the Gen 1 arm. FWIW.
 
iansr said:
One thing that might put off some prospective customers is that this is the first iteration of a product that utilises a new idea and that means it is highly likely that a second, improved iteration will be forthcoming in the relatively near future (assuming the first iteration enjoys reasonable success). Some prospective buyers may therefore decide to defer their purchase and wait for the improved “Gen 2” arm. To counteract this might I suggest you promise a very generous trade up (part exchange) deal against any such Gen 2 arm to anyone buying the Gen 1 arm. FWIW.
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Thanks, this is a good suggestion which has been on my mind. As I've mentioned before, the arm is assembled in a fairly modular way, so I do not rule out the upgrading or addition of individual parts.

There have been six main prototype iterations, the most major change being a switch from aluminium arm tube to carbon-fibre. The sound consistency of all these prototypes as a family has been so good that if I walked out of the room and came back in again I might struggle to tell them apart, and I have a fairly revealing system. My point here is that even with upgrades, I would expect any change in sound to be incremental. I suspect that a well set-up Supatrac arm is approaching the region of diminishing returns in arm performance and I would be surprised if I achieve another major leap in my lifetime.

Another factor is that unlike ball-race/gimbal bearing arms there is little scope for hidden damage to the bearing device itself, so there is not much problem with people returning the arm, or sending out loan arms for trial. While the mechanism needs to be set up accurately for best performance, its components are easily repaired and replaced. It's robust.

But if the design evolves into something new I certainly intend to offer a discount for customers who want to trade-in. Thanks for bringing this up.
 
iansr said:
One thing that might put off some prospective customers is that this is the first iteration of a product that utilises a new idea and that means it is highly likely that a second, improved iteration will be forthcoming in the relatively near future...
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You could say that about any product.
 
Mr Pig said:
You could say that about any product.
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Really ? This is new cottage industry style manufacturer with no track record or commercial profile supplying a first product that has an unproven USP into a fiercely competitive market place. Sonndek clearly recognises these impediments, hence his acknowledgement of the point I made.
This is not to say he isn’t going to be successful, just that he could do with a bit of a following wind, as it were. FWIW I’ve put my name down as an early adopter.
 
paulski said:
Linn fit?
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Yes. It's completely compatible, to the extent that it has the same geometry (229mm length, 24⁰ offset, 211mm spindle-to-pivot) and you don't even need to change the collar or T-kable. It comes with a collar ('base') and arm cable for those who may decide to sell their Linn arms, as you can see.
 
sonddek said:
Not long to go before I start sending arms out now...

boxed.lowrez.jpg
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A few explanatory notes:

Downforce is set by sliding the magnetic tungsten counterweight backwards or forwards, and by removing or adding tungsten bars to the counterweight magazine (bottom right).

Above the counterweight you can see the inertia (effective mass) adjuster. It may not be needed for high compliance cartridges, but can help to ensure low compliance cartridges fill out deeper frequencies. It sits on the arm like a saddle and can be positioned anywhere along its length.

Left above the inertia mass is the high bias weight screw for high downforce cartridges. The standard bias weight screw is half this length.

To the left is a penny and the downforce scale. The downforce scale can use a US cent or Euro centime instead of a penny. To double the downforce range for high downforce cartridges you can use a combination of two coins of the same or differing currencies. Gravity is mostly more reliable than mechanisms or batteries.

As standard the arm cable will come with a 90⁰ din plug but here you see a straight one.

Tools included are three allen keys, spanner and non-magnetic tweezers. I may also include a screwdriver.

What's still missing from this box?
- safety gloves
- manual
- warranty
- half length tungsten counterweight rods
- spindle-to-pivot geometry jig
- cartridge alignment jig
- spare pivot bolt
- spare kevlar suspension thread
- spare polyester bias thread
- optional SME mounting clamp
- pivot bolt guard

Please ask if you have any questions.
 
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