This SMD op-amp project uses the TI RC-4560 dual op-amp chip and a salt water-etched PCB. The builder got the op-amp as a free sample from Texas Instruments and scavenged all of the SMD resistors from old hard drive electronics. The results are not pretty, but they’re functional. The circuit used (with some changes) is the Chu Moy design found here. The CMoy circuit is not SMD.
Op-amp headphone amplifier – Link
- In-line headphone amp – Link
- MAX – headphone amp – Link
- Altoids headphone amp – Link.
- AVR based headphone amp – Link
- Altoids and tin cases Archives – Link
From the pages of MAKE:
Mint-Tin Amp. MAKE 04 page 131. Pocket amplifier punches up headphones. Subscribers–read this article now in your digital edition or get MAKE 04 @ the Maker store.