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Old 1st August 2012, 12:41 PM   #11
limono is offline limono  United States
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It's hard not to hate you but I was looking to get Xerxes too Only it would cost about $800 so I passed for now. I 'll play with LP12 and wait for something to pop out .It almost always do , sooner or later.

PS 50hz pulley for Linn Sondek has 21mm dia while 60Hz has 17mm
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Old 1st August 2012, 07:05 PM   #12
Nanook is offline Nanook  Canada
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Default 17mm 60Hz pulley?

limono: I did the math, and it should be 17.50 mm. Regardless, the replacement of the motor pulley with a factory one should be suitable enough. Any pulley that is the same size as one made for that table for the North American market should be suffice. Minor tweaking can be easily done.

About the Xerxes: Somehow I ended up gifting it to a friend (not my original intent, I wish I had tried it in my system first). We rewired an RB250, put a tecno-weight on it, and a VTA adjuster nut from JAMichelle. The "sagging plinth" had to be addressed, and was done easily with some threaded rod and couple of nuts. The suspect "blobs" (Roxan's nomenclature not mine) were replaced with squash balls to good effect. A Denon DL103r now sits on it feeding a modified Jolida JD9A phonostage.
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Old 2nd August 2012, 12:12 AM   #13
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Quote:
Originally Posted by Nanook View Post
Any pulley that is the same size as one made for that table for the North American market should be suffice.
The stock pulleys are slightly barrel shaped, and are pressed on to the motor shaft, not easy to remove unless you have a small arbor press. The barrel shape gives the user a small speed adjustment.

jeff
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Old 6th February 2013, 12:03 AM   #14
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Default Advice on Hercules PSU for Roksan Xerxes

I've just come into ownership of a Roksan Xerxes and am in need of a power supply. A fellow on ebay is selling a Mose/Hercules PSU (Simplified Mose Hercules II for Turntables Similiar to Linn LP12 Upgrade | eBay) which he noted would work for the Roksan.

Anyone ever used/bought one of these? Do you have a sense of how involved the work would be to get it working with the turntable?

Thank you.

Quote:
Originally Posted by Nanook View Post
The simplest and quickest way to do a speed conversion (non-electronically) is buy the correct motor pulley from the maker of the turntable, or get a new pulley machined if one is not available. As trupaul points out the frequency of the mains determines the speed of synchronous motors. Those of us in North America have 115VAC@60Hz, and Europe usually has 220VAC@50 Hz. The motors themselves are the same motors, just the voltage being fed to the circuitry prior to the motor and the frequency vary.

If one were to create a 50Hz PS, with the appropriate voltage, then you could run a European table here without any other changes. If creating a 60Hz PS, then a smaller diameter pulley would need to be had or as stated above, a 60Hz pulley from the table manufacturer. The math is just a simple equality:

D₁*S₁=D₂*S₂
where the subsrcipt indicates a specific motor and pulley, D is pulley diameter, S is in RPM. To solve for a new Diameter pulley:
D₂= D₁*S₁/S₂

We know that common synchronous motors used in turntables spin at 300RPM in North America, and 250RPM in the UK (for example). We can measure D₁ and know S₁ and S₂. Just plug n' chug.If an Ariston (or Linn or whatever) uses a 38mm pulley in the UK, we then know that it requires a 31.66mm pulley to operate at the correct speed in North America, or we must generate a 50Hz signal and step up the voltage to the point that there is around 80VAC to 90VAC (the common Airpax/Thomson motors as used in many turntables are quietest around 72 VAC, but that could be just for a specific motor example not all motors of that part number).

Don't hate me: I bought a Roksan Xerxes for $150 (in CAD) that required a minor tweaking to the power supply. Once completed it was speed stable. YMMV. I think the final output was 78 VAC@50Hz.
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Old 11th February 2013, 05:24 PM   #15
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I came a crossed this design, TTPSU, which was designed by Jonny Norre (c 2006 DuNo Electronics I/S) for any 2 phase AC motor. Has anyone built one of these? I would like to try it, if I could get a circuit board. The article I found had a Eagle Layout file with the pcb. No sure if a pcb could be made from it? Anyone know where I can get a pcb made?

I attached the document.
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File Type: pdf TTPSU.pdf (293.3 KB, 47 views)
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