New SDS settings


I got a new SDS unit and the voltage drops to 72 V on both 33 and 45 RPM settings upon start-up. In my old unit, voltage would drop to 72 V for 33 and 102V for 45. I called VPI and Steve, who calibrates the SDS before it's shipped, told me that it should be 96 V for 33 and 102 for 45; he also said that the motor would not have enough torque at 72 V for best sound. Are we talking the platter speed being affected more by more difficult passages at a lower voltage? His recommendation was to recalibrate the unit.

I find it interesting as I thought the idea was to get the lowest voltage that would be enough to get the platter spinning. So if the platter spins at 72 V, it would be better than 96 V. I'm also very surprised the 'table works at the 45 RPM setting at such a low voltage.

Does anyone have any insight into this matter, or perhaps experimented with different voltage settings on the SDS? What is the interaction between voltage and sound? I guess the bottom line question is: what voltage is optimal for best sound?
actusreus
Actusreus, the run default voltage for 45rpm should be set for 102v, not 72v, perhaps that is why your 45 listening impressions are less than stellar.
If you're getting good results with 72v on 33 I'd be inclined to leave it there. 72v may be low (in terms of all electronic speed control with the SDS) for 45. Based on this:

http://db.audioasylum.com/mhtml/m.html?forum=vinyl&n=974466&highlight=variac+blake&search_url=%2Fcgi%2Fsearch.mpl%3Fsearchtext%3Dgarrard%2Bzero%2B100%26SelectForumvinyl%3Dvinyl%26SelectForumvinyl%3Dvinyl

I would try 72 and 92 respectively.
Ok, so I tried to recalibrate the unit, and the voltages are set to 96 V and 102 V for 33.3 and 45 respectively. So why and how on earth does my run voltage drop to 72 V?
If the SDS was correctly set to those run voltages, and they
still drop to 72V; the unit is obviously defective. That is
supposed to be the lowest voltage option, for 45RPM. The
45RPM default factory value is 90V for Software Version 1.1
and is 102V for Software Version 1.2, which the unit should
have dropped to, without having been reset, if operating
properly.
With my VPI MK. IV, outboard motor, thread drive, TNT 3.5 platter/bearing, I find the 90v sounds/works best @ 33 rpm.