I received this PSU a month ago. I wanted to compare it against a 50W DIY PSU that I have, which has the so-called R-core transformer. I noticed that although the DIY PSU is good, as witnessed when listening, the GR70 that I have picks up some noise when warming up. However, when connected to the PSU20, the noise picked up is very, very little, which is expected when reaching the tube's optimal operating point. Currently running at the same time with the ZD3, I raised a query to Fosi Audio Support concerning the fact that the rated power of the GR70 is greater than that advertised in the specifications. Fosi confirmed that it is safe. So far, the fan has not even turned on — I guess that's good design. The 5V input is very useful too; I'm using it with portable DACs.

GR70 → DC2 (12V/5V)
ZD3 → DC1 (12V/15V)

Excellent

I used it to power my Fosi ZH3 and S3. It helps simplify the connection to power, One plug less and so far seems pretty good.

The powerhorse of Fosi near to corefusion

Fosi Audio PSU20 Linear Power Supply

Good variety of inputs and sound quality for the price.

I have this powering my LAIV Micro Dac, before and after comparison, i can say that now I can hear more instrument separation and definition and owing to a lower noise floor the soundstage got expanded noticeably. Thanks Fosi Audio for yet another great value product!

While the PSU20 seems fine with a iFi Audio Zen streamer (15v), it most certainly had a negative effect on the quality of sound in the Laiv Audio uDDC it powered (5v). The degradation of sound quality was noted by multiple people and was not subtle. With the Laiv uDDC, powered by the Fosi PSU20, the sound produced was flat, compressed, muddy, uninteresting and nearly unlistenable. Instruments and voices lacked proper timbre and simply didn’t sound right. It resulted in a poor listening experience. As always, your results may vary. I was excited to have one PSU to power both the streamer and the uDDC- but was disappointed.

I hooked up PSU20 to Fosi ZD3 DAC and Fosi X5 Phono preamp - both take 12V DC. For Fosi ZD3, I can sense minor improvement in noise floor (I was using iFC 12V adaptor before). For phono premap, I don't think I get sense any difference from the generic SMPS power supply that came with the unit.

The PSU20 is heavy, and I like the versatility for the output options - dual out with 12V, 15V and 5V options. I might upgrade my phono amp that takes either 12V or 15V, and see if the PSU20 makes any difference.

Purchased to power my GR70 and Box X2. One of the 12V outputs would blink and not power the connected device. Working through a return and exchange now.