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Next turntable project....
http://www.dcaudiodiy.com/phpBB3/viewtopic.php?f=4&t=512		 Page 1 of 6
Author:  Roscoe Primrose [ January 24th, 2015, 3:46 pm ]
Post subject:  Next turntable project....
So, this is on the way:
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May start it out in a plinth similar to what the Denon is currently in, may eventually make one out of soapstone or slate, time will tell ;)

Guess I'm gonna be busy for a while :obscene-drinkingcheers:

Roscoe
Author:  randy warren [ January 24th, 2015, 3:51 pm ]
Post subject:  Re: Next turntable project....
where did you dig that one up? should be a fun project!
Author:  Roscoe Primrose [ January 24th, 2015, 4:15 pm ]
Post subject:  Re: Next turntable project....
randy warren wrote:
where did you dig that one up? should be a fun project!


Found it on epay... Buy It Now price was a bit lower than they've been typically going for, so I jumped on it. It's coming out of Europe, so it's almost definitely a 50Hz unit, but I've already got the parts to do my own crystal controlled 50Hz supply. tomp, that's what I was going to use one of those amp modules for, now I'll just use one channel of a USA400, and use the other channel for crystal controlled 60Hz for some of the other source components.

Roscoe
Author:  tomp [ January 24th, 2015, 6:59 pm ]
Post subject:  Re: Next turntable project....
Should be a clean stable power supply depending on the signal generator. An adjustable signal generator would also give you speed control.
Author:  Roscoe Primrose [ February 4th, 2015, 7:16 pm ]
Post subject:  Re: Next turntable project....
tomp wrote:
Should be a clean stable power supply depending on the signal generator. An adjustable signal generator would also give you speed control.


The signal generator is crystal controlled, using a 30ppm crystal. The table already has a speed adjustment, that's what the cryptically labeled +....- knob is.

It finally showed up today. Doesn't look near as bad in person as the photos made it look. Time to get to work ;)

Roscoe
Author:  Guy [ February 5th, 2015, 8:57 am ]
Post subject:  Re: Next turntable project....
We should remember that most turntables rely on a neon lamp for a strobe that is driven by the line voltage, which in turn is not the most accurate 60-Hz source. Now that your oscillator is well controlled with a 30ppm crystal, it is time to consider the accuracy and tolerance of the strobe. :)
Author:  Roscoe Primrose [ February 5th, 2015, 9:42 am ]
Post subject:  Re: Next turntable project....
The motor and the strobe will be driven from the same source...

Roscoe
Author:  Guy [ February 5th, 2015, 11:08 am ]
Post subject:  Re: Next turntable project....
I knew you knew about this - I wanted to remind the community, too. :silent:

Roscoe is way too smart for me! :obscene-drinkingcheers:
Author:  dberning [ February 5th, 2015, 8:33 pm ]
Post subject:  Re: Next turntable project....
IN case anyone is interested in an accurate 60 Hz source, you can start with a 153.6 kHz crystal and count down. I was working on building a sine wave power source and considered various crystal frequencies that could be divided with various counters to get 60 Hz. Once an accurate 60-Hz square wave is obtained, it can be converted into a sine wave with a couple of cascaded L-C tank filters.

David
Author:  Roscoe Primrose [ February 5th, 2015, 8:40 pm ]
Post subject:  Re: Next turntable project....
My 50Hz source will be based on this: http://www.mouser.com/Search/ProductDet ... 5-UCC3750N

You use a 32kHz crystal for 50Hz, 38.4kHz for 60hz. I bought two of them, will probably build both, run one into each channel of a QSC USA400, and run the TT of the 50Hz channel, and the digital sources off the 60Hz channel...

Roscoe
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