Armageddon clone for LP12 - why such a large transformer? - Page 4 - diyAudio
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Old 5th January 2013, 12:10 AM   #31
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david, I also have one of these power supplies, Roehren-und-Hoeren :: Thema anzeigen - Luxusnetzteil für Synchronmotoren mal anders it has adjustable voltage and quadrature from a synthesised source. I think it's pretty much the finest AC controller you can find, and worth investigating for anyone who uses a 24v motor.

Unfortunately I can't tell you exactly how the plots are achieved as they are created by a 3rd party. Check out the 'turntable speed analysis' thread on pinkfishmedia.net Paulr does the plots.

Fortunately in the UK the mains waveform is rock solid, so the Geddon works very well. It is also much happier into a high drag bearing than most any of the electronic supplies and I find that the added load from viscous drag at the bearing does more to smooth out a deck's speed than pretty much anything else. IME replacing oil with silicon fluid on a deck equipped with an LP12 bearing assembly gives many times the improvement of jumping from a capacitor-resistor controller to the best of the commercially available psu's.
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Old 5th January 2013, 12:48 AM   #32
bgruhn is offline bgruhn  United States
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Originally Posted by sq225917 View Post

IME replacing oil with silicon fluid on a deck equipped with an LP12 bearing assembly gives many times the improvement of jumping from a capacitor-resistor controller to the best of the commercially available psu's.
Very interesting observation. My DIY TT in Corian has a simple slightly loose, bearing nylon, sleeve (about 3/8" thickness) at the top and a ruby thrust ball at the bottom. It depends on tension of the thread belt to keep the polished tool steel shaft in intimate contact with the upper bearing sleeve. This general style of bearing borrowing from the Well Tempered turntables. The motor is an old motor from AR turntables. Been very pleased with it over the years, but since my bearing well is leakproof I wonder if replacing the number 20 weight oil with silicone fluid could provide any benefits. Easy enough to try. I have silicone fluid in many viscosities from very light to very heavy, 10,000cs iirc. If you know, what viscosity did you use? Light, medium or heavy if you don't have values.

Thanks for the info, I'm looking forward to the experiment.

BillG
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Old 5th January 2013, 02:55 AM   #33
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As always a compromise. Higher viscosity will increase drag and belt slip, slowing the rotation a little but will also often reduce the motor vibration.

The bearing sleeve you describe might benefit from being rotated, if the side pressure wears into the side
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Old 5th January 2013, 03:28 PM   #34
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Hardly a compromise, choose the correct viscosity for your bearing tolerance and there are no down sides, no drop in absolute speed and only an increase in measured stability and reduced motor vibration. I use 2000cst Team Associated Silicone Differential Fluid (2,000cst) (2oz) [ASC5451] | RC Cars & Trucks - A Main Hobbies

Bill, Like anything it's easy to make a wrong decision and choose the incorrect viscosity or try it in a bearing where it simply isn't suitable due to tolerances and material choices. Your bearing sounds fine and will probably work with much higher viscosity fluid than the LP12 which is quite tight tolerance. If you use a string drive this may not be a good solution due to slippage, but with a flat belt it's fine.
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Old 5th January 2013, 04:33 PM   #35
Take5 is offline Take5  Germany
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One step beyond: impatient i build up a psu with stock parts of my shelf. Works better like the lipo batteries, no hum, no noise, i´m amazed about the silence.

I think this is also the result of the shunt regulator design, thank you FWD!

Click the image to open in full size.

Next step: sending some bucks to italy, buying some cases. I want build it up like my sold pass pearl:

Click the image to open in full size.
Click the image to open in full size.

Chris
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Old 5th January 2013, 05:09 PM   #36
Take5 is offline Take5  Germany
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Sorry, i posted on the wrong thread!

Chris
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Old 5th January 2013, 05:13 PM   #37
6L6 is offline 6L6  United States
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Regardless of thread, your Pearl is fantastic! I hope to see your MPP when complete.

Cheers!
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Old 5th January 2013, 05:22 PM   #38
Take5 is offline Take5  Germany
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Regardless of thread, your Pearl is fantastic!
thanks!

Quote:
I hope to see your MPP when complete.
Yes, you will see it

Chris
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Old 5th January 2013, 05:43 PM   #39
bgruhn is offline bgruhn  United States
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Originally Posted by sq225917 View Post
Hardly a compromise, choose the correct viscosity for your bearing tolerance and there are no down sides, no drop in absolute speed and only an increase in measured stability and reduced motor vibration. I use 2000cst Team Associated Silicone Differential Fluid (2,000cst) (2oz) [ASC5451] | RC Cars & Trucks - A Main Hobbies

Bill, Like anything it's easy to make a wrong decision and choose the incorrect viscosity or try it in a bearing where it simply isn't suitable due to tolerances and material choices. Your bearing sounds fine and will probably work with much higher viscosity fluid than the LP12 which is quite tight tolerance. If you use a string drive this may not be a good solution due to slippage, but with a flat belt it's fine.
Thanks for the inputs. Draining out the old oil and replacing it with silicone fluid while simple and easy, is messy and not the "gee I've got five minutes let's go type of project" so, it may be a while before I can actually do it. But I would like to comment on the string slippage concern. When I first replaced the flat rubber belt with the very fine thread I did experience some slippage. After making several threads to establish the best tension, I solved the slippage problem by holding a cake of violin rosin thread against the moving thread for a minute or less. That was several years ago and no slippage or breakage has taken place. It is a highly recommended (by me) drive belt and infinitely less expensive than flat rubber belts.

Cheers and Happy New Year,

BillG
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Old 5th January 2013, 10:12 PM   #40
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Rosin, great idea...
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