A while back I purchased a nice pair of cans ... Grado SR80 Headphones. When I bought them, I knew that they would drive me to build a DIY headphone amplifier. Well, here are the results ... A very simple CMoy mint tin headphone amplifier.
The CMoy is a very popular and easy to build headphone amplifier that can be fit into a mint tin. It can be used to drive demanding headphones, produce thunderous volumes and most importantly, it sounds excellent. The original article A Pocket Headphone Amplifier by Chu Moy discusses all the fine points of the amplifier, while How to Build the CMoy Pocket Amplifier provides excellent and easy to follow building instructions.
My version of the CMoy headphone amplifier uses two nine volt batteries, the OPA2132PA (Burr-Brown) operational amplifier (opamp) and I originally set the gain to 9 - which turned out to be far too high. I have since adjusted the gain down to about 3. Since I will be using this with a portable MP3 player, I elected not to include a potentiometer as the volume will be controlled through the MP3 player.
The CMoy headphone amplifier sounds pretty darn good when you consider the simplicity and low cost. It provides excellent clarity, even at high volume. The headphone amplifier does not seem to add its own colorations to the sound and there is a lot of detail. The amplifier is very well behaved and there are no pops when powering up or hiss during operation. Overall, this is a very nice little performer and it considerably increases listening pleasure with a good set of headphones.
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