Thanks for the answer. I suspect these "birdies" are the noise i hear when clients bring bad quality smps with their guitar pedals.
Possible, guitar pedals draw jack all current, ideally you pre-load the PSU enough to waste enough power to get the unit out of "green mode".
But ive made simple pedal supplies with old laptop smps (19v with no earth) with an extra filter stage (usually 7809 and filter caps) to make 9v pedal supplies with good results. no audible noise.
Yes, the cycle skipping noise is audio band and differential (and kinda random and signal dependent (current draw)).
So a regulator with enough overhead Voltage will reduce it significantly.
An LM317, perhaps with enhanced HF rejection and a 12V/2A SMPS would be my take, 1.5 A (given the right heatsink) can drive a LOT of pedals.
I am searching for a new project to use these 19vdc smps (i have 4 of them laying around). Since i posted i did a research and i think a "dc to symetrical dc circuit" may be what i am looking for. Maybe it even has an of the shelf solution already in Aliexpress.
I would go with a suitable switcher in the "1.2 MHz class" and use the classic greinacher cascades from the switching node to make +/-18V and +48V.
Probably make a bit more and use linear regulators plus LC filtering.
I doubt this exists, but it might be cute as community project, with an SMD based PCB that can take in 12V - 24V DC via DC Jack or connect to a USB-C charger and output a lot of volts and AMP's for +/- 12/15/18V and 48V or 68V Phantom power.
If we use my preferred richtek part in push-pull with 180 degree switching polarity and 12V minimum input, we can get as much as 82VA total in a very compact module.
Linear output regulators, using discrete Sziklai based followers with RC filtered Zenner references satisfies both DC accuracy and offers low noise competitive with any IC regulator and really low output impedance, with much greater PSRR than any IC regulator.
I can help on the Design (for free if it's an open sauce project), but I'm not designing PCB's or do the legwork for fabbable (JLCPCB) project.
Thor