Post by Graham on Mar 11, 2018 20:16:07 GMT 12
Hi Guys
As per the title, I'm after a used Valhalla circuit board in any condition but preferably with the on/off switch.
Cheers Graham
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Post by michaelw on Mar 12, 2018 11:53:29 GMT 12
new project graham ?
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Post by Graham on Mar 12, 2018 19:16:48 GMT 12
YEP !!!
I'm toying with the idea of powering the AC synchronous motor in my Oracle Delphi with a Valhalla instead of the Geddon Clone currently in use. I would of course modify it as I have done previously to provide two speeds, 33 and 45. It is so simple to do you have to wonder why on earth Linn didn't do this instead of the silly add on pulley adaptor.
Cheers
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Post by Owen Y on Mar 13, 2018 8:30:07 GMT 12
Hi Graham - how do you see the Valhalla as being different from the Geddon? Synthesising a perfect AC sine wave? You may be familiar with Altmann's DIY TT? The motor control in particular - www.altmann.haan.de/turntable/Keep up the good work
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Post by Graham on Mar 14, 2018 9:27:28 GMT 12
Hi Owen
1) Possibly a better sine wave for even smoother motor operation. 2) 2 speeds when modified.
3) Just for fun and to experiment .
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Post by michaelw on Mar 14, 2018 9:42:35 GMT 12
what about 78s
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Pundit
Post by LinnBoy on Mar 14, 2018 14:58:45 GMT 12
what about 78s And 16
I am a non-recovering audioholic, and Ivor is my higher power.
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Post by Graham on Mar 14, 2018 21:13:18 GMT 12
A synchronous motors rpm is controlled by the frequency being fed to it. Not voltage. The Valhalla has a crystal that determines the frequency of its ac output voltage. Within reason any rpm could be achieved simply by using the appropriate crystal. My modification simply involves having two crystals on a separate little circuit board with appropriate resistors, and a double throw switch to select either to provide the frequency for 33 or 45 rpm. This is actually all that is inside a Mose Hercules PSU. Cheers
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