The headphone amplifier is designed around single or dual-channel op-amps such as Burr-Brown's OPA2134 or OPA2132PA, however, a wide variety of op-amps have been successfully implemented. The amplifier's design is quite simple. It consists of only a few components, can be assembled on a small section of protoboard, has a lower parts cost than other headphone amplifiers, and can run for many hours on a single 9 volt battery.
In spite of this, a well-made CMoy amplifier still cannot drive demanding headphones, like Sennheiser's HD600 but may show marginal improvements on low impedance Grados quite well. These characteristics have made it very popular among DIY hobbyists, especially those who have not built an amplifier before. The CMoy headphone amplifier can be fit into Altoids tins.
No previous experience with electronics is required to complete this project. This project requires intensive soldering. If you do not have prior experience with soldering, it is suggested that you read a soldering guide first.