Three Headphone Amp Implementations Using YDA138-E DIY Board

This pre-assembled board is available through Amazon for about $25, but as low as $9.99.  It's advertised as having sound quality rivaling that of the popular "class T" chip; 2024, and I agree.  I bought my first one to make a simple 3-input, preamp, headphone amp.  I was so taken with the possibilities I created two additional implementations; including a portable one.

Preamp

Crayola Box

Curad Bandage Box

Back panel w/ 12V input.  Top opens to access battery.