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Accurate Turntable Speed Trick

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  • Accurate Turntable Speed Trick

    Hey all!
    It's been a while since I've been back here, but had some information that may be or use to some of you, so I thought I'd share.

    A while back, I was finally able to purchase a new computer from the Tracer team - long over due. Had some quirks with it but Tracer helped with that, and with a little help from both Craig & Rick, I was back in business with my audio restorations. Yay!

    After about 40 LP's (in just a few months!) my linear track table decided to stop pulling the arm down the track - I knew that belt was going, but now? It needed some basic maintenance, adjustments, lubricating, etc. so I guess it's time.

    Like any good audiophile, I had a back-up - After spending an hour or so getting it all set up, I had no sound out of one channel. Found it to be the leads inside the tonearm. Another table in need of repair! NO!

    I had one table left - It has a nice heavy platter with a good working internal 3 point suspension system, but it has a weird twin tube dynamically stabilized (whatever that means...) tonearm set up as a P-mount system. I only have an old Shure V15 HR-P (yes, a P-mount V15!) - needle had low hours, but it's old and always had one channel louder than the other (a Best Buy closeout back in the day...), but that's an easy fix with DC-8.5.

    The one other problem I ran into was unlike my other tables, this one does not have a Quartz Locked speed, and the speed control was way off. There is no strobe on the platter nor do I have a strobe disc. My printer has not been used since my last home pc and it's ink has been dry for years so I couldn't print one up. What I did was use a technique that may be more accurate than a strobe, if your power into your house may not be a true 60Hz. I knew I had some old test records burried away
    so I dug them out and found one with a recorded 1000Hz test tone. I then used the "Make Waves" feature in DC-8.5 to record a 1000Hz tone on the computer, and played them both together. If the speed is not correct, the two tones will "beat" against each other creating a warbling sound. Just simply adjust the table's speed control until they sound the same - speed is now perfectly adjusted.
    Last edited by Craig Maier; 06-15-2020, 04:57 PM.

  • #2
    Hi DJ,

    Good to see you here. Your method sounds good. Another method would be to record the 1000 Hz onto the computer and then play it with the Spectrum Analyzer set to its highest resolution setting in terms of frequency. Then, just point the mouse at the spike and click it and it will give you the actual value of the signal recorded. It may be a good back up test for your listening test approach to be sure that you have gotten it correctly. Of course, the power line in the US is extremely stable on the grid. So, you can print out the strobe disc provided with the software. The printable strobes are found within the Diamond Cut Productions program grouping and have extensions of .wmf

    Craig
    "Who put orange juice in my orange juice?" - - - William Claude Dukenfield

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    • #3
      DJ,

      Nice method to listen for the "beat". Quick and easy, but limited to the low end of your hearing.

      Marc

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