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

Rosewind said:
It would not be hard to replace "the wick" with something fancier-looking.
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I will be supplying a more traditional finger lift with each arm.

Rosewind said:
I really like the way you tonearm looks. Reminds me of one of these Sorane/Abis tonearms but your tonearm has a more sculptural look in the way you have designed the counter-weight:
soraneza12transcription-37.jpg
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That is a beautiful arm. Never seen it before. The lack of vertical bracing at the headshell end does not fill me with confidence about the strength-to-weight ratio though. I admire Kuzma's uncompromising approach to headshells.
 
Mr Pig said:
We've had this discussion, he likes the string. Thinks is genius.
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I don't recall saying it was genius. It's a piece of string. I do think function and use come before looks.

Put your hand up if you allow your 8-year-old and clumsy 10-year-old to cue records and park your tonearm by finger lift. I do. No problems so far. There is no way I would allow that with my Ekos.

I will be supplying a traditional finger catapult^H^H^H^H^Hlift with each arm ;-)
 
Mr Pig said:
It's looking better all the time, but I still don't like the stupid bit of string.
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Wow, if it's looking better all the time, it must have looked like a real bag of nails early on. I think it looks bloody awful, like something I would have lashed together in CSE Metalwork (shows age, CSE was a wannabe O-level back in the day).
 
tobermory said:
Wow, if it's looking better all the time, it must have looked like a real bag of nails early on. I think it looks bloody awful, like something I would have lashed together in CSE Metalwork (shows age, CSE was a wannabe O-level back in the day).
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I know what you mean - my first concerns were
- build the best sounding arm I could design
- make it last forever
- wide configuration options
- wide compatibility options
- affordable at its performance level
- eschew the need for precision engineered parts
- easy to use.

Honestly, how it looked was quite a long way down my list of priorities. Most tonearms are quite ugly knobbly things, awkward, inelegant, industrial-looking. I think a tonearm is for how it sounds. Paintings are for how they look. I know this doesn't hold up when it comes to sales, because people don't have time to listen extensively to all the tonearm options, but I still think there is mileage in a 'not-too-offensive-looking' arm which sounds top-notch and is affordable. It's what I wanted, and I hope there are others out there looking for the same thing.

And yes, you are right, the first prototypes really did look a lot worse! ;-)
 
tiggers said:
Design your own tonearm if you don't like it, but being insulting about it and the designer is not on IMO so how about you STFU for once.

@sonddek, it's looking better and better... some beautiful engineering there.... I wonder how it would go on my Gyro? Hmmmmmm... :D
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Cheers tiggers - but don't worry about my feeelz, I am of the strong opinion that people should be free to say what they think, even if someone may be offended. What length would fit your Gyro? I can cut the arm to any length within reason...
 
Personally, I think it's a lovely looking thing. I haven't used a finger lift in years, always relying on the cueing lever, so I'd be removing the wick.

Is a cueing device planned?
 
yuckyamson said:
I don't let my 8 year old drive my car, either, but I still kinda like a steering wheel instead of a joystick.

Call me nuts.
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Inapposite. It's not a car, with attendant safety concerns, it's a domestic device for playing music. Do you let your 8-year-old switch on lights? When you're sitting in the sofa with a beer at the end of a long day, an obedient 8-year-old child-labourer to turn over records can seem like a life-saver! ;-)
 
Theo said:
Personally, I think it's a lovely looking thing. I haven't used a finger lift in years, always relying on the cueing lever, so I'd be removing the wick.

Is a cueing device planned?
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Planned yes, but not yet included. I also hope to make developments retrofittable when possible. I expect inveterate tinkerers will enjoy this arm.
 
tobermory said:
Wow, if it's looking better all the time, it must have looked like a real bag of nails early on. I think it looks bloody awful.
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It doesn't look like an SME because it isn't one. The guy has thought of a new approach to tonearm design and developed it himself, this isn't an established company with extensive resources. Also, the form follows the function. It looks the way it does because that's the necessary configuration for the arm to work as intended. Mana was often criticised for looking agricultural but it had to be that way to work.

I'm sure if the arm get produced in numbers and is profitable it will get developed and end up looking better. If you see early Audio Origami arms compared to current ones there is a big difference in the quality of the finish. But it's a bit harsh to come down on the finish of a new product which is more or less still in the prototype stage.
 
Mr Pig said:
It doesn't look like an SME because it isn't one. The guy has thought of a new approach to tonearm design and developed it himself, this isn't an established company with extensive resources. Also, the form follows the function. It looks the way it does because that's the necessary configuration for the arm to work as intended. Mana was often criticised for looking agricultural but it had to be that way to work.

I'm sure if the arm get produced in numbers and is profitable it will get developed and end up looking better. If you see early Audio Origami arms compared to current ones there is a big difference in the quality of the finish. But it's a bit harsh to come down on the finish of a new product which is more or less still in the prototype stage.
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Cheers Mr Pig, that's absolutely right. If I can get anywhere in the market I will be refining the product. Although I'm not inclined to upgrade my Sondek much, I do think the Sondek shows that it's possible continuously to improve a product by judicious part substitution. If I can develop worthwhile improvements I will certainly try to keep existing users happy by making them retrofittable. As it stands I see no reason why a Supatrac arm will not work well for your great-grandchildren. The bearing and suspenders are easily replaced with standard parts from any ironmonger. There's no lube. The thrust box is 2.5mm thick steel. There is little else to wear out.

I don't see tonearms as jewellery, I see them as music machines, but if people want a better finish I will learn how to provide it.
 
Very Nice.

What tube material did you use for the first arm sold? Doesn't look like Carbon Fibre. Are you offering a choice of tube materials and lengths?
 
Vinny said:
It doesn't, as such, it damps oscillation of the spring, hence the name. It prevent booooiiiiiinnnnngggg (or however it is spelt).
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The spring-wheel system oscillates in response to forces acting on it via the wheel; remember, the damper is attached to the wheel.

I suggest a review of 'damped oscillations'. Should be section or two on this topic in your high school physics text book.
 
al2002 said:
Very Nice.

What tube material did you use for the first arm sold? Doesn't look like Carbon Fibre. Are you offering a choice of tube materials and lengths?
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It's carbon fibre. Pultruded so that all the strength is longitudinal. The early prototypes were aluminium but I'm pretty sure graphite is better, so I'm only offering cf for the moment. If I find a supplier for bonded bucky rods I'll give that a try ;-)

For the moment you can specify a stylus-to-pivot length. It may settle in to two or three fixed lengths at some point. I've made an arm with >=225mm outer hole for someone who only likes Troikas (7.1mm bolt-to-stylus). Otherwise I'm putting outer hole at about 224.5mm for, say, an 8.5mm bolt-to-stylus cartridge on Linn arm geometry. The pivot bolt and suspender conduit can be adjusted so that spindle-to-stylus suits your cartridge if you have a long or short one. The range is only a couple of mm though, so far outliers will need a custom arm. I expect the standard arm to be compatible after adjustment with cartridges in the 7mm - 9.5mm bolt-to-stylus range. It is a pain that this has never been properly standardised.
 
al2002 said:
The spring-wheel system oscillates in response to forces acting on it via the wheel; remember, the damper is attached to the wheel.

I suggest a review of 'damped oscillations'. Should be section or two on this topic in your high school physics text book.
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If you use a microscope to watch what happens when you deflect your cantilever and let go, it looks like the suspension does plenty of damping.

The damping systems which people attach to arms may be having much of their effect in the warp/eccentricity frequencies where I don't think you want any latency at all. I designed this arm to respond to warps and eccentricities with maximal and undelayed compliance. If the arm is not inert enough you can just slide the included effective mass adjuster towards the cartridge end and rebalance.

A Bentley doesn't tell you more about the road surface than a McLaren, and it's the road surface we're interested in.
 
al2002 said:
The spring-wheel system oscillates in response to forces acting on it via the wheel
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I would suspect that a very young child could work that out, although they, like you, would forget that the spring has to have something to react against, and that is the car, and that moves.

To model the action of a spring and damper with one FIXED end, they are perefctly easily and justifiably regarded as seperate items and then combined. I never went to High School (that was just for girls where I lived). This was all A level Applied Maths in my day.
As I said, the damper stops excessive ocillation of the spring. In car suspension, damp the ocillation of the spring very fast (the favourite of wanna be boy-racers and routine for most types of track sports cars) and you can feel every piece of pea shingle that the car drives over. Have a much "softer" shock-absorber and ultimately the spring ocillates excessively and the ride may cause nausea (sea sickness) as the vehicle body tends to roll all over the place.

sonddek said:
A Bentley doesn't tell you more about the road surface than a McLaren
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But the complete opposite is true.
 
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