ProtoDAC TDA1387 X8 project

[hifinet]

Nelson Pass often uses SMPS for his preamp designs. He triple filters with simple RC filters. I have also seen him use LM317 (60dB ripple rejection) linear regulators at the end. The SMPS DC Filter P089ZB Kit and the other filter posted by @wolf7250 specifically filter noise typically generated by SMPS. These techniques may be enough to adequtely filter noise, and provide continuous power.

I found the LT1963 regulator in this article of listening tests of various regulators. The LT1963 was the highest rated for an IC regulator. I think it sounds very similar to the Chinese Jung Super regulator I tried. It is an LDO with fast transient response and needs the proper cap on the output to prevent ringing (see the datasheet).

Transient response determines a lot of the sound of regulators, ultracaps and batteries. In my tube amps, I use the Maida LM317 regulator. This uses a 2R7 and 1uF mylar cap snubber at the output, which affects the sound quite a bit. It dampens the transient response. Similar to the 10uF ESR up to 3R with the LT1963. Ultracaps have super fast and hard transient response, with no overshoot or ringing, because they can supply huge amounts of instantaneous current. See here and here . LifePO4 vs UC . There are still the sharp vertical lines (barely visible) in the Uc transient response images, probably from stray capacitance/inductance. Sometimes I do hear some harshness (= ringing) with the PurePi 5V UC supply. I wonder if a snubber would help this?