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This is my first headphone amp.|
Once it was completed, I found that it definitely fills out the sound better.
I believe it does color the sound a bit, but damn it's cheap!
I spent about $10 on caps and 1/8" connectors at radioshack over xmas break.
Next time I'll use higher quality components.
It's based on the well known Cmoy amp.(Named after Chu Moy, it's designer.)
Chu Moy's project writeup
Tangent's helpful howto
Features of my amp:
OPA2132PA Opamp, no volume control, single 9v powercell.
4.3 operational gain thanks to the 3k/10k r3/r4 resistor combo.
Tuned for my 3rd generation iPod and low impedence headphones (16 and 32ohm).
Works nicely with my powerbook, at around 3-4/10 volume.
220uf power caps perform reasonably.
.22uf input caps add some extra give to the input lines.
These auditioned better than the .1uf caps.
There is no dual 10k pot on the input. This cuts a significant cost.
The lack of pot is actually more towards the orignal design, so I didn't stress over it.
I insulated the bottom of the case with laserprinter transparency.
Hot glue was applied along the resting area of the battery. No rattles
The Everest gum tin is smaller than a penguin or altoid tin, cutting some size.
Obligatory glowing led shot. Mine is pretty dim to conserve battery power.|
Generous hot glue holds it in nicely.