thought about the power supply (+15V or +/- 15V) for the ES9038Q2M (or the other Chinese-Boards, its basically the same); my bought,“normal“ 220V adjustable power supply has only 12V DC max and so i thought about another way; had a month ago a power supply for a Thinkpad T43, 19V i think, was sold and got today a HP power supply (for some printer)->32V..
2 (4) possibilities: either u buy directly a power supply from amazon/ebay/aliexpress->3$ and up
or use an old, unneeded one, like this HP one for printer for example, or laptop or something and buy a cheap „Step Down Power Regulator/Module“ from Aliexpress (of about 1,50$ and up)-> https://de.aliexpress.com/item/1pcs-5A-High-power-75W-DC-DC-adjustable-step-down-module-LED-Voltmeter-Power-supply-module/32688669737.html
Input Voltage (this modul) 4-38V DC
Output Voltage 1,25-36V DC
Ampere max. 4A..
i read elsewhere that the ES9038Q2M only needs about ca. 500mA..so normal laptop or printer power supplies should be enough (this HP power supply has 625mA)
cut off the plug, and so u have your 2 wires to connect to your power step down module (or directly), adjust the right output voltage and wire it with 2 lines/cable up to the ES9038Q2M; easy as this 😉
(BUT, soundwise its really,really better to use a toroidal dual 15V transformer like this (25$)-> https://de.aliexpress.com/item/115-V-230-V-30-Watt-R-typ-transformatoren-Dual-15-V-Dual-6-V-ausgang/32833217523.html)
(or the ultimate HiFi-High End choice would be a „battery-pack“; for example a bike-battery 😉 😉 (12$+charger)
but for the „cheap“-beginning the above choice should be enough.. 😉