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U-Turn Orbit Turntable

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Re: U-Turn Orbit Turntable

Postby analogaudio » 15 Dec 2013 19:00

The stylus friction in the groove causes a force that swings the arm in towards the center, called skating force. Because the groove walls are at 45 degrees, the center-directed sideways force alters the balance of downforce on the two opposite walls, the inner wall receives more pressure, the outer (right) wall receives less, maybe 20-30%. There are two consequences. Stylus wear is unequal on the two sides. Tracking ability is unequal, during loud pieces the right channel mistracks before the left. Antiskate force is provided to cancel these negative effects.
Ted

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Re: U-Turn Orbit Turntable

Postby abs1 » 15 Dec 2013 20:31

analogaudio wrote:The stylus friction in the groove causes a force that swings the arm in towards the center, called skating force. Because the groove walls are at 45 degrees, the center-directed sideways force alters the balance of downforce on the two opposite walls, the inner wall receives more pressure, the outer (right) wall receives less, maybe 20-30%. There are two consequences. Stylus wear is unequal on the two sides. Tracking ability is unequal, during loud pieces the right channel mistracks before the left. Antiskate force is provided to cancel these negative effects.


Your statement is arguable in real-world situations. As an example, you should note that skating force changes as the stylus progresses from the outer to the inner grooves of the disc. This means that the anti-skating compensation is only truly accurate at one spot on the disc. Your statement about stylus wear MIGHT be correct in theory but can't be proved in fact when styli from a properly setup arm/cartridge combination are examined under a powerful microscope.

Cheers,
Al
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Re: U-Turn Orbit Turntable

Postby johnnywalker » 15 Dec 2013 21:03

Does anyone know the effective mass of the tonearm? It looks like it would be fairly low, perhaps not as light as Dual's ULM, but pretty close by the looks of it. The AT-95e's compliance is fairly low (6.5 at 100Hz, probably around 10-11 at 10Hz), so I wonder what the resulting tonearm/cartridge resonance would be. Could be a little high. I look forward to seeing an evaluation from someone who has a test record and can determine the resonance.
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Re: U-Turn Orbit Turntable

Postby analogaudio » 16 Dec 2013 00:08

check the information here

viewtopic.php?f=46&t=17293

about variation of skating force with radius, figure 9 shows the range of values across the side of a disc, it is reported to be between 90 and 100% of the maximum value, we are not dealing here with something that starts and stops at a certain place on the disc, it is continuous across the disc.

You say something cannot be proved, are you sure about that? that is a sweeping statement. You can believe what you wish, it is a free world :-)
Ted

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Re: U-Turn Orbit Turntable

Postby BMRR » 18 Dec 2013 18:43

A couple of U-Turn Orbit updates:

They are now selling an add-on device that automatically lifts the tone arm when it reaches the end of the record.

Buyers of the Orbit Plus now have a choice of two cartridges: the AT95E (standard), or the Grado Prestige Green1 ($20 extra).
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Re: U-Turn Orbit Turntable

Postby howardpgh » 19 Dec 2013 19:50

Change that pulley's diameter and it could be a nice 78 rpm turntable.
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Re: U-Turn Orbit Turntable

Postby BMRR » 19 Dec 2013 21:43

I had a similar thought, actually. My guess is that it would be pretty low on their priority list, but perhaps it's something they could think about at some point down the road. :)
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Re: U-Turn Orbit Turntable

Postby fscl » 27 Dec 2013 16:39

OK, I'm on a 4 day vinyl binge listening to my Orbit...... :shock: :D Yep, records barely sleeved, perhaps close to their jackets and large random piles at each of the systems that I've plugged the Orbit into "phono in"....... :shock: :D

Flashback to the 23rd, finish up business in Boston metro before noon, set the GPS for Conn Street and I'm off for local pick up my Kickstarter unit.

28066 28067

Follow the hand drawn plan of occupants / tenants and walk to Suite I, it's quiet but there's signs of activity behind the U-Turn door so I knock and I'm greeted by Peter (whom I mistake for Ben as he's been my email contact arranging for local pickup).

Find out Peter is a Berklee music grad, guitar and bass +, so I asked if they would be interested in listening to a Baduzium LP which I had brought (to put on one of their Orbits...) so go back to the car and bring in 5 test LPs and my Sony PS-X555es.

Ben comes down from the upper inner sanctum [basically more heated along with a nice listening setup(s)] made famous in the Kickstarter video as the office and the stairs were the major players in the packaging demonstration...... :)

So I start discussing the unipivot design with Ben explaining that questions of that nature should get answered by designer Bob who gets locked up in a room way in the back. Except by now, he has slipped downstairs and spies the tangential. I ask how the unipivot is done and rather than try to explain it rushes upstairs grabs a handful of parts brings them down and uses them in a show and tell.....it's a brilliant design elegant and simple but still requiring "touch" to assemble correctly. Bob has assembled all of the unipivots on all the U-Turn turntable tonearms to date and mentions that FE analysis is used in the design of the pulley and belt vibrations. He explains even the tonearm rest / lock rubber durometer selection details are sweated.... :shock: =D>

Though it appears simple, there's been a lot of thought, design, engineering, prototyping and tweaking on this turntable. The ability to model, predict and then prototype with modern software and computer (Mac Powerbook) is just amazing. I remind Bob, that back in the day, we were working with 3 significant figures and sliderules...... [-o< [-o<

I brought the Sony because I figured that the young guys never experienced / seen how complex turntables had evolved towards the end of the reign of vinyl. Pushbutton automatic start, stop and cueing. Failsafe sensor detection in case there's no LP on the platter. Bob diagnoses my unit's noisey tonearm drive motor with his stethoscope...... :oops: :oops: (Looks like I'm going to have to go in and renew the rubber dampening..... ](*,) )

28064

I"ve become a PITA so decide to pack up. Peter helps me to the front with turntables and LPs. I'm estatic to collect my Orbit. =D> =D> :D

Fast forward and back at home base, I've thrown every LP, blues, jazz, jazz fusion, rock, prog rock, piano, piano jazz, horns, vocals, female vocals, bass, drums, durm battles, 45s, 45LPs, new age, strings, classical and this little Orbit has spit it back in the form of pleasing sounds and great vinyl playback.

The Orbit has acheived what U-Turn has set out to do and greatly exceeded my expectations for a starter (and beyond) deck. OK, the chorale vocals on Beethoven's 9th 4th movement is a bit congested, however the OM Omega was very acceptable.

The Omega is set at 1.8Gr VTF and has been sounding / tracking beautifully..... Haven't backchecked the alignment / protractor, however, really haven't had to as I haven't experienced / am aware of any distortion / IGD. I'm happy my unit has the OM as it's easily upgradeable (I've got a modified plastic Digitrac nude elliptical that I'm itching to slip on). The OM style cartridge also makes manual hand cueing / placement a breeze...... I was a bit leary manual cueing but it really hasn't been a problem..... Target audience should have steadier hands than I.

Wow specs may be a bit high especially compared to something like the Sony PS-X555es, however, I didn't detect / couldn't perceive any wowing on piano pieces.

With the turntable level, the Orbit tonearm skated down the lip of Johnny Winter 2nd Winter but slowed down and ended up sitting maybe 3.5 - 4" from the center spindle on the blank side with the platter turning. The Orbit tonearm skated somewhat quickly to the middle label of my Grateful Dead Dick's Picks Volume 2 blank side.

Life on VE has just become so much easier..... since there's a new generation discovering plastic analog playback, it's a no brainer to be able to recommend the Orbit. It's new, low cost, sounds great, plug and play with choice of cartridges, easily upgradable / tweakable for those experimenters...... and it will definitely NOT ruin your vinyl.

I'm truly impressed and wish the U-Turn Audio team good luck for 2014 and years to come.

Fred and happy to have been behind this Kickstart project and reaping in the reward...... :D

* Affiliations: Ben and my daughter were part of Northeastern's Entrepreneur Club, she sent me a link to U-Turn which I posted to the VE, I'm a U-Turn Kickstart backer, however, I'm really a happy Orbit owner, the turntable sings for itself...... =D> =D>
Music is Everything....Except Predictable....WFUV Fan.
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Re: U-Turn Orbit Turntable

Postby satanfriendly » 27 Dec 2013 17:06

Good to finally hear anything back on the U-Turn fscl and even more so something in a positive light. It is one of these companies which kind of gave a good feeling.

I have been in contact with U-Turn myself and understand they are looking towards the European market, maybe during this next year.

May you continue to enjoy
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Re: U-Turn Orbit Turntable

Postby BMRR » 27 Dec 2013 17:20

Wow! Thanks so much for taking the time to post your story and photos, fscl! That's great. I've had several pleasant e-mail exchanges with the U-Turn folks myself. I'm envious that you were able to visit them in person. I'm actually not that far away from their headquarters -- probably about a 2-hour drive -- but I can't afford to make the trip right now, and I'm sure they're VERY busy... but it's great to know that they were so friendly and welcoming. I think that says a lot.
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Re: U-Turn Orbit Turntable

Postby jwspicer1 » 27 Dec 2013 17:54

Nice seeing this. The performance specs and cart options are not bad at all for the market and users they are aiming for. Better than a lot of things at that price and can see a nice mod culture developing around it.

Noticed mentions of the Technics machines (SL-BD series). That could be extended to the DD and QD series too. But KAB is the most reliable source for those, and they are only doing the BDs. The others require looking in the wilds of the used market and eBay. I got lucky with most of mine, except for an SL-20 shipped by someone who assured they knew how to ship a turntable. My ***, that thing was packed so bad it was mortally wounded by the time it got here. One point though, automation will have to enter the equation eventually if vinyl is ever to get past the hobbyist/uber-audiophile/nostalgia crowd. Casual listeners, especially those that have grown up on CDs and digital files are not going to put up with the "thump, thump, thump" at the end of the record for long. And a lot of kids these days are lazy.

So nice to see this though, and a cueing lever is not optional. Hope it grows from there.
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Re: U-Turn Orbit Turntable

Postby Alec124c41 » 27 Dec 2013 23:32

I remember reading a slide rule to 3 places, and rounding off to 4.
I expect a better cartridge will open up the congested passages.
I't is good to have an actual user report on this, and to have an affordable turntable to recommend.

Cheers,
Alec
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Re: U-Turn Orbit Turntable

Postby robgil » 28 Dec 2013 02:28

abs1 wrote:
analogaudio wrote:The stylus friction in the groove causes a force that swings the arm in towards the center, called skating force. Because the groove walls are at 45 degrees, the center-directed sideways force alters the balance of downforce on the two opposite walls, the inner wall receives more pressure, the outer (right) wall receives less, maybe 20-30%. There are two consequences. Stylus wear is unequal on the two sides. Tracking ability is unequal, during loud pieces the right channel mistracks before the left. Antiskate force is provided to cancel these negative effects.


Your statement is arguable in real-world situations. As an example, you should note that skating force changes as the stylus progresses from the outer to the inner grooves of the disc. This means that the anti-skating compensation is only truly accurate at one spot on the disc. Your statement about stylus wear MIGHT be correct in theory but can't be proved in fact when styli from a properly setup arm/cartridge combination are examined under a powerful microscope.

Cheers,
Al


Thats not entirely true of a lot of tone arms antiskate mechanisms, for instance, mine uses a spring that puts more tension on the arm as it travels over the record. The real question is with an arms ability to do this accurately or at least adequately.
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Re: U-Turn Orbit Turntable

Postby fscl » 14 Jan 2014 22:21

Thought I would put the Orbit away by now as it's full manual and resume the use of the Technics SL-QL1 since I'm lazy.... :-k but that has not been the case...... :shock: :D =D>

It's current location is to my right, right by the computer I work at sitting on top of the QL1..... which sits right on top of an Adcom GFP-555...... :shock: The location lends itself to a manual table and so after reading jives11 "Automatics - why?", decided why not and give the QL1 a bit of a break and go full manual with the Orbit..... \:D/ \:D/ I'm pretty much at the phone / keyboard / monitor during the day and can pay the attention a manual demands..... :) The Orbit with Ortofon Omega sounds wonderful through the 555's phono stage feeding into the VCR line input of a Nak Stasis receiver feeding a mini HT...... :D

Putting myself in the shoes of newbies here on VE, I've tried to teletransport myself to the first tt I purchased with paperboy & caddie money. It was a Sony PS-1800a which has since seen the inside of a skip, tossed in a fit of rage..... :( What I do seem to remember is that this Orbit sounds so much better than that Sony semi automatic shod with a Shure M91ED..... =D>

Downside..... well not only do I have accumulated paper for work but also a lot of unfiled / random LPs sitting at my feet and having to be extra careful not rolling them over with the office chair...... :shock: #-o :D

Fred and relearning how to steady my hand cueing....... :)
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Re: U-Turn Orbit Turntable

Postby cafe latte » 14 Jan 2014 22:55

Finally we have a decent new budget TT to recommend. No more daft threads about buying a Lp-120 as it is the only turntable around 200 bucks you can buy new. Now there is the U turn orbit which seems to perform very well for similar money. If the U turn comes to Aus I might just get one out of curiosity, plenty of room on the TT shelf :D
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