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Old 27th September 2010, 11:47 PM   #11
lowpoke is offline lowpoke  Australia
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I just love it. And I'm glad it sounds great too!
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Old 28th September 2010, 12:01 AM   #12
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Originally Posted by The Space Egg Corp View Post
Hi Cactus

Love the TT and unipivot.
Am doing a TT refurb myself at the moment.
I have an arm to use on it, but would love to have a go at one of my own.
Great photos, have saved them in my gallery.
Very inspiring.

Cheers Simon...
Hi Simon and thanks for the comments.

If you're halfway handy with tools, give it a shot. It was a fun project and it's very satisfying to be hearing the results.
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Old 28th September 2010, 03:55 AM   #13
tmblack is offline tmblack  United Kingdom
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Interesting, where did you get the sapphire bearing and how much does it cost?
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Old 28th September 2010, 04:57 AM   #14
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Interesting, where did you get the sapphire bearing and how much does it cost?
The pivot and matching vee bearing were from Small Parts, Inc. I think if you scroll up and look at the photo of the parts (in plastic bags) you might make out the part numbers. Cost was minimal as I recall, dunno if I could locate the invoice. I bought the parts a couple years ago, and have had this project in the back of my mind for some time. I also bought a small idler pulley from them and plan to use it for string-and-weight antiskate device.
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Old 28th September 2010, 01:13 PM   #15
wjlamp is offline wjlamp  Greece
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Originally Posted by cactuscowboy View Post

I'm very happy overall with the project, but became aware of a design flaw well into the process. That being the configuration of the headshell.
An excellent turntable,as I can tell by the pictures.But speaking of flaws,there is one more.Why do you use a parallelogram beam for the main tonearm? A quick study in motional physics,will show that ,it is the worst shape for a tonearm,resonance wise. By using a round tube,wooden, metal ,plastic,the resonances generated in the tonearm ,are distributed on the walls in a linear manner and safely routed to the base.
The rectangular tube behaviour in resonance is uncontrolable,it twists the beam and creates problems to the lateral stability of the arm ,in relation to pivot and the cartridge.

B.L.
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Old 28th September 2010, 03:56 PM   #16
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An excellent turntable,as I can tell by the pictures.But speaking of flaws,there is one more.Why do you use a parallelogram beam for the main tonearm? A quick study in motional physics,will show that ,it is the worst shape for a tonearm,resonance wise. By using a round tube,wooden, metal ,plastic,the resonances generated in the tonearm ,are distributed on the walls in a linear manner and safely routed to the base.
The rectangular tube behaviour in resonance is uncontrolable,it twists the beam and creates problems to the lateral stability of the arm ,in relation to pivot and the cartridge.

B.L.
B.L.,

Thanks for the input, it is appreciated.

As I began this project, it quickly became evident that the laws of physics were an important consideration. Factors such as balance, distribution of mass, and center of gravity, etc.... I lack formal training in physics, so I proceeded based on intuition and 'gut feeling' more than anything else.

Admittedly, the lateral stability of the tonearm could stand to be improved upon. As we know, virtually every record made exhibits some degree of warp and off-centeredness. So, as a record plays on this turntable, there is a slight side-to-side rocking motion to the tonearm, ranging from barely noticeable to more pronounced, depending on the quality of the record and degree of warp. Azimuth is constantly changing as a result, albeit to a very small degree. I'm hard-pressed to notice any audible changes related to azimuth, but that's not to say they don't exist. Overall, it is a very fine-sounding tonearm.

Now that I've successfully built an unipivot tonearm, I'm eager to begin the second tonearm, improving upon the first and further refining the design. So many factors come into play, for example, optimizing the design while accomodating different cartridges which themselves vary in size, shape, weight and position of stylus tip in relation to mounting holes. Type of material to be used? Wood (different types of wood), metal, carbon fiber, or plastic. So many questions, so many choices. But I suppose that's what makes it challenging and fun.
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Old 28th September 2010, 04:08 PM   #17
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Originally Posted by cactuscowboy View Post
The pivot and matching vee bearing were from Small Parts, Inc. I think if you scroll up and look at the photo of the parts (in plastic bags) you might make out the part numbers. Cost was minimal as I recall, dunno if I could locate the invoice. I bought the parts a couple years ago, and have had this project in the back of my mind for some time. I also bought a small idler pulley from them and plan to use it for string-and-weight antiskate device.
Further information.

Website:

SmallParts.com: The Hardware Store for Researchers and Developers

Cost two years ago was $17.50 for the vee bearing and $4.65 for the pivot.

I was very impressed with the quality of this bearing. During the building process, I had the big lag bolt (w/vee bearing) held in the vise out in my shop. The tonearm (sans tonearm wire) was in place, with cartridge mounted and balanced perfectly. I blew gently on the cartridge. This set the tonearm in motion, spinning very slowly. It rotated for a full five minutes before coming to a stop.
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Old 28th September 2010, 04:15 PM   #18
wjlamp is offline wjlamp  Greece
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Originally Posted by cactuscowboy View Post
Further information.

Website:

SmallParts.com: The Hardware Store for Researchers and Developers

Cost two years ago was $17.50 for the vee bearing and $4.65 for the pivot.

I was very impressed with the quality of this bearing. During the building process, I had the big lag bolt (w/vee bearing) held in the vise out in my shop. The tonearm (sans tonearm wire) was in place, with cartridge mounted and balanced perfectly. I blew gently on the cartridge. This set the tonearm in motion, spinning very slowly. It rotated for a full five minutes before coming to a stop.

Very impressive.

B.L
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Old 28th September 2010, 04:56 PM   #19
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Howdy CactusCowboy - Congrats on a great build!!
I'm guess'n you have have seen this linked thread - but juuuuust in case..... my latest iteration of "Nanook's 219 tonearm"..

Nanook has a good thing going here and it looks to be right up your alley for your phase II build.
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Old 28th September 2010, 05:26 PM   #20
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Default "Tonearms should be made of wood." my father always said.

Hi Cactus

My father was an engineer in materials and electronics and a big music lover.
He was very much a DIYer in a lot of things (cars, furniture, photography etc. not diyAudio though), and I for sure got the make it yourself bug from him and my grandfather who made his own cameras.

"Make your tonearm out of wood son, t'will be much better."

I think I would conceptualy have to agree.

I have at home a set of well made commercial wind chimes.
They have a nice decay to them, but make no audible sound unless struck by the chimes mallet (not strictly true actualy, you can get a slight organ pipe/flute effect if the wind happens to catch them right).

I thought it would be interesting to make some wind chimes with a much lower frequency and longer decay.
Three chimes were made each 182cm long, in 1 1/2", 2 1/4" & 3 1/2" diameter aluminium alloy tube.
With holes for a hanging wire 1/4 way down the tubes, which I figure is a ideal distance to get them resonating nicely, very low, long decay frequencys were produced easily.

Thought I'd have a go at a cowbell and woodblock next, forgeting the cowbell for now, the wood block proved impossible to get any amount of decent resonance or sound from despite trying various shapes deliberately designed to try and promote this.

Anyway to cut a long story short, if you hang a 2x4 a dowel or a log next to the ally tube wind chimes and give them a bash with a mallet, what do you get resonance or sound wise,

THE SWEET SOUND OF NOTHING.

Cheers Simon...
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