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VPI Scout running FAST...help?

Ladies and Gentlemen-

For your consideration, I present my very first world but very real audio problem.

Proud (sorta) second owner of a VPI Scout One. 11.5 Acrylic platter, 600rpm motor. Approx 3 years old, appears very little previous use.

At the present, the table is running at a steady and consistant speed of 34.6 and 47.1. I have tested the speeds using my ears (songs sound too fast), a strobe, the old fashioned counting RPM's over a 3 minute period, and even so far as to have a friend bring over a centerfuge calibrator from a medical lab. So I am certain that these are the speeds it is presently running.

Things I think I have ruled out:

Belt is new, but not brand new

Table is on a flat, level surface

Pulley is attached soundly in the motor

The reported speeds are at the top "rung" of the pulleys, I am aware that the higher up the pulley the belt is, the slower the platter turns.

Outlet power is ok, I have tested the table on multiple outlets and it is the same, also, my older Pro-ject table ran a consistant 33.5 on the very same outlet.

This is where I run out of ideas. I have placed an e-mail and call to VPI, but have not heard back yet. Anyone have any ideas? Goin crazy here...

Thanks in advance-
thebambino
pbnaudio's avatar
pbnaudio
1,613 posts
 
As mentioned above it sounds like you have a motor pulley for a 12 inch Platter
and are running it on a 11.5 inch Platter, it will give exactly the deviation you
mention.

The math is pretty simple, 12 / 11.5 x 33.333 = 34.78 rpm

The speed of the motor is determined by the number of poles in the motor
combined with the line frequency it attached to, it will only deviate if the line
frequency changes. Also a less than optimal drive system will only cause the
platter to run slower due to slip, it will never run faster only a higher line
frequency can cause that.

Good Listening

Peter
cerrot's avatar
cerrot
1,700 posts
 
I bet its the motor. I also bet VPI doesnt call you back anytime soon. Sorry, guys, but I am a VPI owner and I just cant get an email back from those guys. I know they are only in on the days that the moon is alignied with Io, but still...

I did get an awesome upgrade by going from the motor you have to the upgraded one, and, for a grand, maybe the way to go-you should also add the SDS (another grand).
thebambino OP
19 posts
 
Thanks all for the replies, much appreciated. I did forward this thread to VPI and got a response from Ian, who had me send some pictures, but then the line of communication went silent again. Bummer. I may consider the upgrade to the 300 rpm motor at some point, seems pretty basic and not all that expensive. I'll try and keep you all posted if/when this gets resolved.
thebambino OP
19 posts
 
Hey guys-

Got ahold of Matt at VPI today, and I just need to send out the 12" pulley and they will send one back for the 11.5" platter...any tips on how to take off the pulley? Is it a tiny little hex nut on the bottom of the pulley itself? The rest of the Scout uses a 5/64 hex, this one seems smaller? Thanks in advance!!!
brf
1,715 posts
 
The pulley has a small allen key grub screw. Just back off the grub screw and the old pulley will slide off.
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