Cmoy
Encyclopedia
Headphone amplifier
A headphone amplifier is an audio amplifier designed particularly to drive headphones instead of loudspeakers. Most commonly they are found embedded in electronic devices such as integrated amplifiers, portable music players and televisions, but standalone units are not uncommon.-Consumer headphone...
originally designed by Chu Moy on the headwize.com Headphone Resource Site and public discussion Forums.
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. The CMoy headphone amplifier can be fit into Altoids
Altoids
-Flavors and varieties:-Mints:Altoids mints are available in eight flavors: peppermint, wintergreen, spearmint, cinnamon, ginger, liquorice, crème de menthe and cool honey. "Sugar-Free Smalls", tiny square mints sweetened with sorbitol and sucralose, are also available in peppermint, wintergreen,...
tins and can often be found for sale on eBay
EBay
eBay Inc. is an American internet consumer-to-consumer corporation that manages eBay.com, an online auction and shopping website in which people and businesses buy and sell a broad variety of goods and services worldwide...
by searching for "CMoy".
Circuit
A typical CMoy consists of two identical AC coupledCapacitive coupling
In electronics, capacitive coupling is the transfer of energy within an electrical network by means of the capacitance between circuit nodes. This coupling can have an intentional or accidental effect...
, non-inverting operational amplifier circuits each with a 100kΩ input impedance.
Power is supplied to the opamps using a dual power supply, which effectively divides the input voltage source in half to create a virtual ground
Virtual ground
Virtual ground is a node of the circuit that is maintained at a steady reference potential, without being connected directly to the reference potential...
. Many virtual ground circuit options are presented in the various CMoy tutorials found online.