Correcting drifting with Sutherland Timeline


Just had a couple of days setting t/t speed using my newest purchase - the Sutherland Timeline Laser timing tool and thought I would share how good it is, once I got my head around how best to set-up and use it.
The supplied one page instructions are vague to say the least and it took me time to settle on which wall I was looking at to see the laser projection settle.
But once I got that fixed, it was easy to make minute adjustments on the VPI SDS and easy to correct drift and pitch. I found that using a sheet of graph paper 'blue-tacked' onto the wall behind.
Astonishing to see the effect that the addition of the periphery ring clamp to HRX platter had on RPM. Never before have I been able to recognise and so accurately use adjustment of SDS khz and hear the pitch snap in to focus.
scousepasty

Showing 1 response by dougdeacon

First I've seen of this cool device, great concept. Every high end TT manufacturer should use one during product development and QC testing - if they dare.

All Teres belt drive tables self-compensate for drift by monitoring a built-in platter strobe and tweaking motor voltage as necessary. This system should maintain overall speed accuracy to well beneath the resolution of the Timeline, since the platter strobe read by the motor controller has more marks per revolution. However, only a few tables have that ability to directly monitor PLATTER speed and self correct (direct drives presumably, but not many others).

With regard to different LP's, I suspect stylus drag due to differing dynamics affects speed more than the mere inertial difference between 120g and 200g records. Once the platter's at speed a heavier LP would help slightly, but 80g more weight is pretty tiny compared to the weight of most platters, especially the 30-80 lb. monsters some of us use.

A ring clamp provides much more inertial benefit than a heavier LP: it weighs alot more and that weight is all out at the periphery. No surprise yours made a visible/audible improvement.

Of course a once-per-revolution strobe cannot measure short duration speed changes that occur and correct in less than a revolution. Short transient rise times occur in far less time than this. Still, steady-state speed at the right speed is certainly laudable - and audible to many if it's off or (especially) changing.

Good report, sounds like it could help many of us make audible improvements ... or change TT's!