Yet another hobby I enjoy is electronics. When I was a teenager I got into electronics by building headphone amplifiers. I found that a really fun way to make something that I could spend a lot of time using. I built many amps from portable battery powered amps to larger desktop units I used with my computer for a long time. Eventually I built a full size power amp which I am still making use of after almost 20 years.

I took picture of four of my favorite amps from that period of my life. The first amp, the large wood colored one, is my speaker amp. I has 2 completely separate channels. Separate transformers, power regulators, and opamps. All these amps are just opamp based, nothing transistor based. I never got that deep into it. But I did have a lot of fun with the opamps.

The second amp, the big black one, is my desktop headphone amp. I have 2 different inputs and the bottom knob is an input switch. I had lot of fun with this one. I used a fancy power supply designed by Kevin Gilmore for high end audio gear. It is basically just a toroidal transformer running through a dual full wave bridge rectifier (for positive and neg DC voltage) with each side running through two stages of voltage regulation so the final output is super stable. The amp board itself has two stereo opamps per channel. So each channel, left and right, ran through a total of 4 opamp circuits then through a final buffer where I figured out I could just stack them on top of each other, so 4 buffers per channel too. The final result meant that when the bass hit, the amp has the power to produce that bass fast and clean.

The other two amps pictures are battery powered amps. One of them is my travel amp (the one with the black knob) and the other one was repurposed from a headphone amp to act as a preamp booster in-between gear with the composite RCA jacks. There was a time when my dad had a DVD player or something that output the sound really quite and he wanted it louder, so I made it louder.