Ripple Rejection You May Not Believe
Our new test setup and old ripple rejection source shows that the redesigned Superpower continues to perform beyond our expectations. To see how Superpower compares to other commercially available regulators, an SPJ78, SPM78 and 5 other regulators were tested. Here is what we measured, where higher numbers represent better rejection, thus less ripple that gets to the regulator output:
The test is done as described below using ±0.5V sine wave on top of 15Vdc. The new
ultra–quiet design and better test equipment means low frequency PSRR is now visible above the
noise floor starting at about 500Hz. It measures -90dBV at 40KHz!
Our customers' comments that their systems sound so much better with Superpower are backed up by measurements—order one to hear for yourself, it really is this good.
To see our original PSRR page with real world measurements of power
supply ripple removal, go here.
If you would like to see spectra of the other devices, contact
us via email at
The source fixture uses a DC+AC driver based on the LM3886 as seen in the schematic below (click for full view). The LM3886 has wide bandwidth, sufficient output power and slew rate to deliver a good sine wave on top of a DC voltage.
We did direct comparison measurements by setting up the fixture, calibrating Vin and frequency and plugging in each of the regulators in turn. Test conditions:
- Load = 240Ω
- Output current = 50mA
A 16 bit 195K sample/second autoranging A/D was used for the FFT measurements.
A 4¾ digit true RMS DMM was used to calibrate the RMS value of Vin(ac) to 0.3535V
after each frequency change. Measurements were made from 50Hz to 40KHz.