back-words... diy hobby...

Tuesday, July 10, 2007
diy hobby...
here's something fun i scoped out. i dig diy projects. enjoy...

source:
http://tangentsoft.net/audio/cmoy-tutorial/
How to Build the CMoy Pocket Amplifier
completed amp, outside

Chu Moy designed a very popular headphone amplifier that's easy to build, and it can be built small enough to fit in a pocket, power supply and all. It's powerful enough to drive very inefficient headphones to thunderous volumes from even weak sources, and it sounds excellent considering that you can build a bare-bones CMoy amp for just US$20, and a pretty nice amp for under $50. Considering that the cheapest of the worthy commercial amps is $100 and most of them are in the $200+ range, this is a very worthwhile cost difference.

For these reasons, I think that the CMoy pocket amplifier is an ideal project to get started in audio DIY. This article is written for the beginner DIYer, though if you just want a guide to building this particular amp, you can skip to the parts or assembly sections.

If you are a raw newbie and don't yet have any tools, see the companion article, Getting Started in Audio DIY.

Last major update: 2007.05.10 (revision history)

o Frequently-Asked Questions
+ Who should build this amp?
+ What if I don't understand the circuit?
+ How can I modify the circuit?
+ Is it a speaker amplifier?
+ Is it a guitar amplifier?
+ Is it a microphone amplifier?
+ Can I make it drive multiple sets of headphones?
+ Can I get someone to build it for me?
+ How long will this take to build?
+ What are the differences between this tutorial and the original article?
o Schematic
o Part Lists and Suggestions
+ Required Parts
+ Optional Parts
+ Precision Resistors
+ Are 1/8W Resistors Sufficient?
+ The Radio Shack Metal Film Resistor Assortment
+ Circuit Board Alternatives
+ Choosing an Op-Amp
+ Choosing an Enclosure
+ Notes on Jacks
o Assembling the Amplifier
o Tweaks
+ Tuning the Gain
+ Quieting Noises (R5)
+ Adding a DC Power Jack
+ Picking a DC Wall Power Supply
+ Using Different Caps
+ Tweaking the LED Resistor
+ Improving the Virtual Ground Circuit
o Article Revision History