It can do that and indeed I have planned to run such tests.
PS Audio's regenerators (at least, the earlier ones) let you create different waveforms for the AC power output, and called it a good thing.
"Playing around with different waveforms, PS Audio's engineers heard differences, sometimes for the better, sometimes for the worse, usually with tradeoffs. Eventually, they settled on one approach: a modified waveform with a wider peak than a sinewave has. PSA says this waveform recharges power-supply capacitors more effectively than a standard sinewave, which makes sense: The waveform is at or near its highest for more of the cycle. In the P10 and P5 Power Plants, MultiWave is available in six strengths, with each progressive step correlating with increased capacitor-charging time (and thus decreased power-supply ripple); the P3 Power Plant offers just one MultiWave setting.
https://www.stereophile.com/content/ps-audio-perfectwave-p10-power-plant-ac-regenerator "
How exactly that is supposed to through the next transformer in the chain is beyond my payscale (seems like maybe it really wouldn't) but, there you go.
From the original much older
Power Plant P300 Manual:
MultiWave II Waveforms [sin] SineWave In the sine wave mode the Power Plant will generate a perfect sine wave (50-120Hz).
[tub] TubeWave TubeWave is specifically designed to optimize the performance of tube based audio products. TubeWave uses the same pseudorandom generation of frequencies as MultiWave2 waveform, however it utilizes more “tubefriendly” frequencies.
[P-1] MultiWave1 MultiWave1 is a single 60Hz sine wave with a minute amount of 3rd Harmonic sine waves mixed together to form a single partial square MultiWave. This is an improved version of PS2 from the original MultiWave™ series. The partial square wave setting improves the power supply’s ability to charge the capacitors in equipment by extending the length of time available to "top off" the capacitors' voltage. Use this setting to enhance the performance of both source and power equipment.
[P-2] MultiWave2 MultiWave2 is a 60Hz sine wave that incorporates a pseudorandom collection of frequencies which are dithered from 55- 65Hz. Using this slightly random frequency deviation is similar to adding dither on a digital audio source. Power supply dithering can lower the perceived noise floor and help remove apparent glare on the audio signal.
[P-3] MultiWave3 MultiWave3 is a combination of P-1 with a slight degree of 3rd harmonic addition (P-1). Try this setting and see how the audio sounds and the video looks. All systems can respond differently to each MultiWave pattern.
Audio Buddy has a P300.
Martin Glasband (of Equitech) figured any "improvement" came from its Balanced Output.
I use an Equitech.