Towards High-End with the AH90 - notes on linear power supplies
I use the AH90 with a linear power supply (LPS) since two months now and wanted to make that post for a while but haven’t had the time. Now here you go:
(1) Stock power supply:
As can easily be seen on one of the official product pictures, the AH90 is powered by a
Hi-Link HLK-20M12 switched mode power supply. This is a cheap 3€ component. Find attached the datasheet (english). Relevant technical specs are:
No-load rated output voltage 12.0±0.1 Vdc
Full-load rated output voltage 12.0±0.2 Vdc
Short time maximum output current ≥1700 mA
Long time maximum output current 1600 mA
Voltage regulation ±0.2 %
Load regulation ±0.5 %
Output ripple and noise ≤150 (mVp-p)
Of course there are (what I believe) filtering components on the AH90’s pcb, so the actual ripple/noise is likely lower. I am not sure whether the 12v dc input is also passed through that filtering stage or not, but for simplicity, this is the spec to beat when choosing a LPS for the AH90.
The manufacturer gustard mentioned multiple times in this thread that the input voltage can be 12-15V and a minimum of 2.5A are recommended for a LPS. Assuming that a higher voltage increases components thermal losses and potentially reduces longevity, I decided that I want to power my AH90 with 12v. Note that many options below are available in a 15v version.
(2) List of compatible options I considered:
[EU price excl. vat and taxes; consider 1.00€=1.07$].
- DIY option
- [sub 100€] cheap generic AliExpress LPS
link
- [100€]
LHY AUDIO LPS25VA
- [150€]
Fiio PL50 (2023)
- [150€]
LHY AUDIO LPS50VA
- [220€]
pd-creative SUPER LOW-NOISE PSU – 12V DC (EU-only)
- [240€]
ATL Audio L-50
- [250€]
ifi iPower Elite
- [265€]
LHY AUDIO LPS80VA
- [290€]
SBOOSTER BOTW P&P MKII
- [300€]
ATL Audio L-50-v.2
When it comes to these options, I wanted to maximize technical performance at a threshold price that still makes sense relative to the AH90s price. For me, this threshold price is 200€ net so that the whole package would be 700€ net on a DAC, headphone amp and streamer with a linear power supply. The next best option that has all those features in one box is (to my knowledge) the
hifiman serenade r2r dac, for 1100€ net. So 700€ net would still be an excellent value.
(3) What I decided to do:
Unfortunately, I found that most of these products provide only very limited information on their technical performance. Most relevant for audio is ripple and noise performance which is often provided in different units that are hard to compare and sometimes not specified at all. The pd-creative is noteworthy as each unit ships with a measurement report. The AliExpress options seemed to be best value for money at first, but customers often report poor quality and randomly changing components such as capacitors. I also question whether they are CE certified and if it’s a good idea to keep them running in absence.
What I then did is look for DIY options. There are many LPS boards that just need plugging a transformer. See
examples on Audiophonics. What I ended up with is a product called
LinearPi Mk II Dual (see datasheet
here). This is a dual output LPS board that is build around a LT3042 linear voltage regulator. The LT3042 is considered exceptionally quiet and ideal for sensitive systems (see specs
here and technical article
here).
To power that, I use a
Block RTE100/12x2 100VA toroidal transformer. This solution should provide excellent technical performance. I use the second output for my network switch right now but I plan to power a phono stage with it at some point. Also at some point I’ll put everything in a steel case with en
emi-filtered IEC inlet, but right now I just appreciate the open look.
(4) Does it improve sound?
Yes. The difference is actually quite noticeable to my ears which surprised me. I would not go so far and say 'day and night difference', but worth spending 200€ (also considering the DIY fun and second output). Describing the exact differences in sound would be super subjective, so I won't.
Note that the manufacturer of the LinearPi
IanCanada is launching a LinearPi Pro at some point with a higher power rating. The normal LinearPi is running quite hot and if I were in the market for a LPS right now I would probably wait for that or consider spending more for a higher power option.
Hope you find this helpful!