1. Home
  2. analog
  3. 1402281618

Speed Control

I've had a Classic 3 for about 1 1/2 years. When I first bought it, I used the KAB strobe to determine it was running spot on 33 1/3 RPM.

Recently I added an SDS. At 60hz it was running fast. With the SDS adjusted to 59.81hz, it runs at 33 1/3 RPM. Any ideas on the impact of -.19hz difference in speed?

At the correct speed it has a much wider soundstage. It sounds like it is playing in a room much larger than my actual room. I have a lot of acoustical room treatment (absorption and diffusion) so that my contribute to the difference.

My system is Benz LP (re-tipped) > Classic 3 > Sutherland Hubble > VK32SE > VK75SE > Eggleston Rosa. I use the record clamp and ring.
bigby
brf
1,699 posts
 
AC motors are sync to the line frequency not the voltage. Line frequency in the US is highly regulated and controlled and does not deviate as much as line voltage.

If you use the Platter Speed test record and associated mobile app, you can set you table's speed compensated for stylus drag.
rodman99999
3,557 posts
 
Interesting points, under subheading #5, here: (http://tf.nist.gov/timefreq/general/pdf/2125.pdf) How they accomplish it? A decent analogy, in the third post, here: (http://boards.straightdope.com/sdmb/showthread.php?t=446800)
jmcgrogan2's avatar
jmcgrogan2
6,346 posts
 
Thanks for the clarification and the tip on Platter Speed Brf!
riffer
362 posts
 
The KAB is smaller than a 12" LP, so you can just run the test with the KAB on top of a playing LP.
needfreestuff's avatar
needfreestuff
386 posts
 
I could not believe my strobe was that far off until I used the Sutherland Timeline. In combination with my SDS to adjust the speed everything now sounds correct. Best of Luck
More to discover