Phoenix Engineering speed control


I purchased the Phoenix Engineering speed control for my VPI Classic 3. I purchased  the bigger power supply and the tachometer combination of the speed control.  I notice that I can hear a steady hum coming from the speakers when the speed control us turned. The hum is constant and will not vary if I turn up the volume on the Preamp.  But the hum goes away when I turn the turntable off. The hum return when I turn on the turntable again. I even in unplugged the interconnect from the turntable, but it make no difference.  Does anyone with the Phoenix Engineering speed control experiencing the same issue?
almandog

Showing 3 responses by phoenixengr

sbank is correct, the hum is cause by a grounding issue.  The Eagle PSU uses a switch-mode power supply so the 3rd wire on the AC output is isolated from the wall socket ground.

If you are using a step up xfmr, ensure that the table's audio ground wire is connected to the phono pre-amp ground. Some SUTs can isolate this ground connection.

Try one (or both) of these:

Ground the case of the Eagle amplifier by attaching a ground wire to one of the rear panel screws;  connect the other end to a grounding point on your system.  Start at the phono pre-amp, main pre-amp, main amp or wall socket.  You may have to experiment to find the best location.

Isolate the 3rd wire ground on the table's power cord by using a 2 prong adapter; connect a ground wire to the adapter ground tab (3rd wire) and connect to your system's ground.


Can you clarify: display flashes?  Does it display 5 dashes or an RPM reading?   You can put the display to "sleep" with a long press of the on/off button (back panel) or it should blank ~ 5 minutes after the platter stops rotating.  Sometimes, surges or static shocks can cause the sensor to trigger which will take it out of sleep mode, but it should blank again in 5 min.