Superpower compared to a Shunt Regulator
All the flavor with no calories! If heat is measured in calories, Superpower uses very few calories compared to a shunt regulator. The shunt we measured looks like the one here: http://www.tnt-audio.com/jpg/ph_21.5_reg.jpg. Components are on the bottom and the top is mostly 2 heat sinks. This model has a maximum output current of about 220mA as you can see below.
Beyond the size and heat issues, shunt regulators also need several volts of overhead at Vin, known as drop out. This one is no exception, with a drop out of 4V to 5V.
Ripple Rejection
Superpower's extreme output isolation again delivers better ripple rejection than any other regulator, even a shunt. This graph shows the level of AC output voltage compared to an input sine wave superposed onto the DC value of Vin, so the lower the value the better the performance. The shunt regulator has rejection (PSRR) in the -100dB range across the audio band, and also had 2nd and 3rd harmonics that are not shown here that are in the main audio band. Superpower has -115dB at very low frequencies such as those of a mains power supply. This gives about a factor of 6 advantage to Superpower!
Dynamic performance
The Superpower has low noise comparable to the shunt as you can see in the photos below. Keep in mind however, power supply noise is a secondary consideration in amplification systems—it's well known that the primary contributor to noise is the amplifier input noise and not the supply noise.
The measurements were made by pulsing a power transistor to sink 200mA from a Hynes and from a SPJ78 Superpower. Superpower Vout=5V, shunt Vout=15V (it can't go as low as 5V).
Superpower, 200mA pulse
5V SPJ Superpower at 200mA. Bottom trace shows Vload
across a ½Ω load resistor.
Top trace shows Vout to ground. Notice the fast transitions, clean settling and low noise.
Superpower, 1A pulse
The SPJ78 can easily supply 1 amp of output current. Bottom trace is Vload
across a ½Ω load resistor, and vertical scale is 400mA/div.
Shunt Regulator, 200mA pulse
Shunt delivering 200mA. Bottom trace shows Vload
across a ½Ω load resistor. Top trace shows Vout to ground.
The response is very fast and clean and noise is very low.
Paul Hynes shunt regulator when maximum current is exceeded. Notice that an attempt to get more
than approximately 220mA results in failure to regulate Vout. Bottom trace shows 100mA/div.