Wednesday, August 13, 2008

little ideas

I made a headphone amp that runs off a 9-v battery
and powers stereo headphones off stereo line-level
cords. Each channel is like this, as you go through it:

---a 100K ohm volume ctl on the input
(center wiper goes to input)

---a 50 uF input capacitor (10 would be OK)

---the base of a 2n2222 transistor is biased via
9v----20k-ohm---(base)---20k-ohm---gnd
(the capacitor feeds into it as well)

---the emitter goes to ground through 100 ohms

---the collector is fed by 9v through 33 ohms

---the emitter is tapped through 200uF for output to
headphone channel

Very smooth glassy-clear sound. You can put the output
of a little walkman phone plug through, and the bass will
open way up.

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The best deal in audiophile super-fidelity
headphones is Grado SR-60s at about $70

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