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

Howdy said:
Nice and congrats, even at first glace this tonearm has come a long way from Ekos Killer Price? days.
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BTW, not very much has really changed since the first Blackbirds went out. The principles of the bearing and construction remain the same, and the price (£2300 for 9 inch) is still near the bottom end of the price range discussed on the first page of this thread, despite the introduction of dealer and distributor margins. I'm making less per arm than I was.

What has changed is that people are installing the arm on decks from Kronos, Brinkmann, SME, Grand Prix Audio et alia, not just Linn and VPI, and they are reporting unprecedented results. Quite soon I'm expecting to see it on a Döhmann Helix.

Hearing is believing.
 
sonddek said:
BTW, not very much has really changed since the first Blackbirds went out. The principles of the bearing and construction remain the same, and the price (£2300 for 9 inch) is still near the bottom end of the price range discussed on the first page of this thread, despite the introduction of dealer and distributor margins. I'm making less per arm than I was.

What has changed is that people are installing the arm on decks from Kronos, Brinkmann, SME, Grand Prix Audio et alia, not just Linn and VPI, and they are reporting unprecedented results. Quite soon I'm expecting to see it on a Döhmann Helix.

Hearing is believing.
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Hi there, has anyone put one on a Gyrodec or Orbe yet? Still about a year away from completing my house, but I'll be trying one of your arms on my Gyrodec for sure when the time comes.
 
tiggers said:
Hi there, has anyone put one on a Gyrodec or Orbe yet? Still about a year away from completing my house, but I'll be trying one of your arms on my Gyrodec for sure when the time comes.
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Hmm. No Michell customers spring to mind as yet. I foresee no problems - if I recall correctly those decks are Rega length/Rega mount. A gun metal Blackbird would look quite nice on one of these...
michel11.jpg
 
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VTA said:
Perhaps not much has changed but I do have to plug your customer service which is absolutely stellar!
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Actually, a few people have been waiting for arms or updated parts for a while this summer. I'm working non-stop and I thank everyone for their patience. I hope all will be satisfied in the end.

IIRC you have a very low serial number with the original pre-magnetic thrust box. When you send it to me you will get the following upgrades:
- braid hoists
- magnetic bearing/thrust box
- six-hole bias rotor
- latest stiffer bias rig
- peg pot
- VTA adjuster
- lever lift
- steel counterweights
- current mass adaptors
- improved Black Knight (DIN connector)
- arm rest rod
- improved SME clamp
- latest manual
- better Supatractor
- pivot bolt tool

I think that's all!
 
Nero said:
Gosh, that’s a lot of evolution. What serial numbers?
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I am unlikely to have time to answer that question soon if ever. One reason for that is that from the twenties onwards the serial numbers were stamped on the thrust boxes but not necessarily sent out in chronological order. This occurs because if you're trying to get ahead of orders with different paint finishes and different lengths, obviously the arm-tube manufacture and assembly timing gets complicated. I still have several perfectly good thrust boxes with low serial numbers ready to go. Some thrust boxes from the early exchanged arms have been refurbished - they are made of steel after all - so a low serial number can be quite up to date, as you can see from my post above. VTA's arm is one of the few early arms which has not been exchanged and lacks the magnetic pivot update, so he is owed an arm, and if I'm doing the magnetic pivot update it will be completely stripped down and may as well come up to current Blackbird spec. After all, accurate VTA control and a lever lift are worth having now they're here, even if you never use them.

I can give a very rough idea from memory of serial numbers of changes, but it's guesswork and I'll be completely wrong:
~15 - braid hoists
~25 - magnetic bearing/thrust box
~25 - improved Black Knight (DIN connector)
~30 - steel counterweights
~30 - six-hole bias rotor
~40 - current mass adaptors
~40 - latest stiffer bias rig
~40 - peg pot
~50 - better Supatractor
~70 - lever lift
~75 - VTA adjuster
~75 - arm rest rod
~80 - improved SME clamp
~80 - pivot bolt tool
 
Correction: the arm rest rod is only for Farpoint Blackbirds, original Blackbirds still rely on the rest magnets. It's a lot of details to remember.
 
Just to be pedantic...

Technically, it's not a sideways unipivot as the bearing in question is only acting as a thrust bearing. The actual bearing which the arm swings on and supports the wight of the arm is the thread? The arm does not pivot on the sideways point bearing?

Not that I think it matters. It's still a very clever design and clearly works very well. Just saying.
 
Mr Pig said:
Just to be pedantic...

Technically, it's not a sideways unipivot as the bearing in question is only acting as a thrust bearing. The actual bearing which the arm swings on and supports the wight of the arm is the thread? The arm does not pivot on the sideways point bearing?

Not that I think it matters. It's still a very clever design and clearly works very well. Just saying.
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ISTM:
The arm does pivot on the sideways point bearing. I consider the whole apparatus to be the bearing because within a gravitational field a sideways uni-pivot can't work unless something stops the motor from falling off. The sideways uni-pivot is a bearing because it stops longitudinal movement of the arm in one direction and sense while allowing the other desired movements. That's enough to make it a bearing. Whether it opposes gravity or not is immaterial. Not all bearings oppose gravity, but they do all constrain some axis of movement while allowing others. Correct me.
 
sonddek said:
ISTM:
The arm does pivot on the sideways point bearing.
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Doesn't it also pivot on the string/thread? Doesn't the thread support the full weight of the arm? If so, isn't the primary bearing the thread?

I'm not knocking the arm at all, just playing with semantics. I don't care what it's called, I think what you've thought of and built is very impressive and I hope it does very well in the market. It's great to see an original bit of thinking for once and enough drive and practical expertise to back it up. Brilliant stuff.
 
Mr Pig said:
Doesn't it also pivot on the string/thread?
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Hmm. It doesn't significantly pivot on the hoists because they do not obstruct or interfere with the bearing's two primary freedoms of movement, yaw and pitch.

Mr Pig said:
Doesn't the thread support the full weight of the arm?
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The hoists do support the weight of the arm against gravity, but in use there is scant net acceleration in that axis. Both gravity and arm weight are static, not dynamic. Therefore this isn't a critical function of the bearing, and this is probably why I've never been able to hear much, if any, difference between hoist materials and configurations.

Mr Pig said:
If so, isn't the primary bearing the thread?
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The primary bearing is the pivot point because it controls the principal reaction of the system to accelerations/dynamic forces. Dynamic forces on the hoists are deliberately minimal - by design. The pivot point sucks up the great majority of impulses from the cartridge.

Great questions!
 
sonddek said:
Hmm. It doesn't pivot on the hoists because they do not
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How so? Doesn't the arm hang off the string? I've seen a picture or diagram of the arrangement but I can't remember it exactly. I thought the arm hung on the string and point bearing limits lateral movement.
 
Mr Pig said:
How so? Doesn't the arm hang off the string? I've seen a picture or diagram of the arrangement but I can't remember it exactly. I thought the arm hung on the string and point bearing limits lateral movement.
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Not much point talking about this when a ten second video can remove all mystery:

 
Mr Pig said:
Very clever. Looks tricky to set up?
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Easier than most uni-pivots, as reviewers have noted, because when you set a parameter it stays that way.

http://www.supatrac.com/manual.pdf

The manual is pretty thorough at guiding you through set up.

There's also a quick set-up/maintenance sheet:
http://www.supatrac.com/calibration

The protractor is quite simple:
http://www.supatrac.com/protractor229.pdf

I'm always available by telephone, zoom or email to help with set-up.
 
Today Döhmann Audio is showing off its superb Helix Two Mk III turntable at the Stereonet hifi show in Melbourne with a SUPATRAC Blackbird Farpoint and Koetsu Blue Lace cartridge:

https://www.facebook.com/video.php?v=701885138169767

I had a call from Mark Döhmann yesterday after they had set up the room. He and his team seem to be very excited by what they are hearing, and whatever you think about the high-end, he does know his way around a turntable!

They had not planned to use the Blackbird at the show, but they got one installed on a Helix a few days ago and it seems the temptation was irresistable ;-)
 
SUPATRAC Blackbird is being demonstrated right now at PAVS in Paris in room 335, with Cary amplifiers and Tessiture speakers. If you're near, come and say hello!

paris.jpg
 
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