Phoenix Falcon Turntable Speed Controller – Power Supply Upgrade
As with many Hi-Fi and audiophile products designers often have to hit a price point. One of the most common ways of cutting costs is to use an external and inexpensive switched mode power supply that has already been UL approved. While these supplies can be designed to be as clean as an analog supply, at a cost, that is rarely the case as they are used to cut costs.
Falcon Inside Top View
Falcon Inside Botton View
For the Falcon the use of an external switched mode supply is probably thought to be of little concern as the control of the turntable speed is created through digital techniques, the use of transformers and extensive filtering, the resulting AC signal is then used to drive a turntable motor NOT some highly sensitive analog electronics.
There is also an associated Roadrunner tachometer that displays the turntable speed that, if required, can provide a feedback signal to the Falcon for even higher resolution speed control. The Roadrunner also uses a low cost external switched mode supply.
After installation I found that the Falcon switched mode low voltage DC power supply cable was radiating noise and needed to be routed well away from both the phono amplifier and in particular the phono cables. Surprisingly the Roadrunner switched mode DC power supply cable did not seem to radiate any significant interference. This maybe due to its very low current demand and/or design.
After appropriate phono cable and DC power cable routing I could not hear any noise, but I knew that it would still be induced into the surrounding rack metalwork, grounding systems, and potentially appear, at very low levels, in signal paths. So I decided that through abundant caution the Falcon switched mode supply had to go.
The Falcon 15VDC, 600mA (1amp) switched mode supply,
was swapped for a low noise, analog 100W toroidal power supply sold by Small Green Computer.
Swapping supplies could not have been easier as the new analog supply came with a full range of DC connector adapters allowing the supply to be simply plugged in with no modifications. All that needed to be done was set its output voltage to 15VDC using the small internal potentiometer. Please see here for more information.
(I do not recommend this power supply for very sensitive audio equipment like phono MM and in particular MC amplifiers as its power supply noise characteristic is not ideal. For all other low noise applications this supply should work just fine.)
So what changes occurred? As expected, only one. Placing my MX-VYNL or associated phono leads in proximity of the 100watt power supplies DC power cable did not induce any noise or hum. Nor did I hear any changes to my vinyl sound. Now I know that the Falcon switched mode PSU is no longer inducing/radiating any noise into my phono replay system. Peace at last…….well almost!
For now the Roadrunner switched mode supply will be kept, as it would appear not be to radiating any detectable noise.
However, I am sure that eventually this 9V 100mA switched mode supply will also be replaced with its analog counterpart……just in case!
See my original Falcon PSU overview here.
Small Green Computer analog supplies here.
Read the Falcon Operators Manual here.
