VPI SDS use question

Mark:

I'll have to check when I get home, but I think I've seen the SDS display 115 on start up. Then it ramps down to 72 after the start up sequence is complete. If I turn the table on and set it to 33, it ramps up to 84. I only used the SDS briefly this weekend as I had family in from out of town. I'll try to give it a full work out this evening to see if it drops the voltage back down to 72 after getting the platter up to speed.

Ok.

I believe it was once our wise fellow agon member Nsgarch, who gave good, valuable advice about the VPI SDS, in that the lowest ramp down voltage of 72V may not always be the best-optimum choice per a given application.

Although, I myself have never experienced a speed fluctuation issues running at 72V ramp down voltage, on a HW-19 Table, with 16lb MK-IV Platter, there may be possible applications-instances with ultra heavy Platters, or due to increased bearing drag, that critical speed stability "might" be better attained at a slightly higher ramp down voltage setting. Again, hope this helps.
Mark

I posted at audio asylum, directly to Harry Weisfield of VPI,, the possible issues about initial voltage at the SDS, which I believed should be exactly 115V.

Harry concurred, and said yes, that start up voltages should be 115V, and if not, to give him a call ASAP.

When I fire up my HW-19, I first turn on the SDS. It will read 115V, then drop to the selected ramp down voltage, which in my instace is 72V.

Then, when I hit the power button on the side of my HW-19, to get the Platter spinning, my SDS will automatically ramp up to 115V for a short period of time, then automatically ramp back down to 72V,

A pretty slick device, I'm real happy with mine.

In conjucntion with my KAB Strobe Disc, and with the record in play, (The strobe disc is slightly smaller than a 33-1/3 LP, and permits accounting for Stylus drag) I get dead stable speed on my rig at 33-1/3 at exactly 60.17hz.

I get the exact same results when switching to 45rpm, (up to 115V, then down to 72V) but forget my personal "hz" settings offhand.

That the strobe doesn't waver-budge 1/32" from dead on for countless minutes. That's multitudes better than what I got minus the SDS in my system. Mark

markd51

Mark:

Thanks for your input. When I turn the SDS on, it does start at 115 and then drops to 72 after a few seconds. I printed out the calibration manual and when I got home, I looked at my settings and my SDS was set to 84 for 33.3 and 102 for 45. My software version looks to be 1.1 so I reset the corresponding speeds to their factory default of 72 and 90. I also have a KAB strobe. My 33.3 setting is 59.83 and my 45 setting is 80.80. I'm still gotta fine tune my settings, but things look pretty spot on.