Just chanced upon this amp. It's said to be a 2.1 amp with built-in DAC, DSP, WiFi, Bluetooth, Optical & Ethernet connectivity. And it sells for less than $100. Tempted to order one.
www.arylic.com
Disclaimer: I have no affiliation with either the reviewer or the seller.

2.1 Amplifier for DIY Speaker Up2stream Amp 2.1
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Disclaimer: I have no affiliation with either the reviewer or the seller.