Amp in a tin can (or what to do on a boring saturday afternoon)
What to do on saturday afternoon when one is extremely bored ? Build an amp out of materials found in junk-box and use tin can for enclosure of course :)
The amp is based on upc1230H2. It is an old NEC chipamp in SIL package configured as bridge amplifier designed for car stereo applications. Its power output is around 15W at 13V according to datasheet.
Wasn't expecting much from these chips as the datasheet states quite high distortion figures, but when I built the amp, I found it quite satisfactory. It's not audiophile stuff, but it does its job well.
For supply I used 9V AC adapter from an old US Robotics modem. Since it supplies only 1A of current, I "overdid" the capacitance to decrease the voltage sag and provide enough juice on transients, so it has around 22000 uF in total. I had a lot of low voltage 2200uF and 4700uF electrolytes hanging around, so thought, why not use them for this. Because these chips have low PSRR, filter capacitors are organized as CRC filter which I must say added a lot of weight to bass compared to low capacitance supply and PC power supply which I used to test the chips before.
The flaw of these chips is that they have very high gain set internally (55dB) and consequently produce more hum than what is expected to be normal. However, not enough to be heard from listening position.
Heatsinks and wires are reused from old broken power supplies, and the tin box is a wristwatch casing.
For power indicators I used blue LED's mounted underneath the box so they are illuminating the surface on which the mini amp is standing.
I like it...especially the blue lights.
Love it! Neat little project. Congrats :)
LOVED it !!!
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