Music and linear power supply have been always a good match. The main problems of LPS is extremely inflated pricing and no data.
Using a transformer will not automatically give you a better PSU. Worst is that most of manufacturers include no testing... no data that can help chose one. We mean to change that.
First, we started with the transformer. There are many types of transformers, some are worse than others (noise coupling, electromagnetic interference). We chose one of the best transformers for noise and emi, r-core.
The transformer has a dual output (galvanically isolated) 5.2V 3A and 5.2V at 1.2A so you can power multiple devices (RPI 4, 3 + DAC, Katana, BOSS, or other) and we used independent (of course since they are isolated) filtering on each rail. First a capacitance bank (massive) to reduce the 50/60Hz noise, then an active filter, followed by an LDO to keep voltage stable. Since LDOs have poor transient and impedance, we used a last active filter (with good transient) and then capacitors more than 15.000uF but most importantly, super capacitors on the output. Final power comes in fact from super caps... transients and impedance of the LPS is... very good.
At last, Shanti includes AC line filter and AC side is earthed to casing. A few words on what we achieved. Measuring noise (in real word scenario) we see about 80nV (0.08uV of noise from 0-20Khz) at the floor of our AP machine. This is comparable to batteries from our internal testing.
As explained, Shanti is not only shining because of the ultra-low differential noise and common mode noise, but because of incredible low impedance / deep reservoir of electrons at the output of the PSU.
Shanti Noise Graphs
|Type of Adaptor