Why is output impedance important?

A power supply is a source of current from a fixed voltage. Any impedance at the power supply output (zout) is in series with the load impedance being driven by the supply. The supply impedance and the load impedance form a voltage divider, so as the load requests current from the supply, the voltage at the load will change by the amount zout * iload.

Thus lower zout delivers fundamentally better voltage regulation. Watch the first three minutes of this video from Texas Instruments to learn more.

SPX Output Impedance vs. Frequency

What is Superpower's output impedance? Amazing! Here is a graph of Zout vs. frequency, showing a 50mΩ maximum impedance while delivering 10mA from 20Hz to 200KHz. This is measured on a typical production SPX78 with 12V out.

Zout vs. frequency

What are we showing you?

In this test, a 10mA AC current is pulled from the regulator output (top trace, at 10mA/div), as frequency of the current is swept from 20Hz to 200kHz. The AC voltage appearing at the output of the regulator (bottom trace at 50mΩ/div by using a gain of 1000 amplifier) represents the output impedance, where zout=vac/iac. Voltage is graphed on an oscilloscope where you can see frequency change across the horizontal axis at 20kHz per division.

SPX zout stays low across ten times the audio band. We dare you to find or build a better regulator! Take a look at our Zout comparison page to see how SPX compares to other available voltage regulators.


This site is being gradually updated. If you have any problems please email super@belleson.com

The Industry Standard SPX

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  • 5V to 30V output
  • World's lowest output impedance
  • Superb ripple rejection (135dBV)
  • Instant step response
  • Extreme low noise
  • TO-220 footprint
  • No thermal pad needed!

High Voltage!

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  • Variable output 5V to 450V
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  • Low output impedance
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SPHP—1000 Watts for your music server!

SPHP, a 10A Superpower with adjustable output voltage from 5V to 100V

  • Same low noise
  • Same blazing step response
  • Same great ripple rejection.
Just lots more current and much higher output voltage. For sale on our order page See more information in the data sheet here.

Build a power supply

A PCB and parts list for building a compact dual positive or positive+negative power supply are on this new page.

Transformer Calculator!

Use the Belleson Transformer Calculator to calculate the minimum Vrms voltage of a transformer for your Superpower based supplies.

It's Official

We're proud to announce the U.S. Patent and Trademark Office has granted patent 8,294,440 to the Superpower design.

Use the Superpower regulator in...

  • Headphone amps
  • DACs
  • Buffers
  • Clocks and reclockers
  • Preamps
  • Microphone preamps
  • Phono stages
  • Phono motors
  • Tube preamps and input stages
  • Line powered guitar effects boxes
  • Anywhere an extremely clean, quiet, dynamic power source is needed