Best toy... I mean tool I ever made

Cmndr Brain

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My other hobby is playing guitar. You may ask how that relates to this forum. Well, it's amazing what we can use to help us repair our machines. For my guitar I made a little cigar box travel amp. The beauty of this thing is that it runs on a wide range of voltage, 3v-12v dc, and it's light and portable. It's an easy circuit to build. The only bulk of it is the speaker, but I chose a large one for guitar reasons. Recently, I had to fix the Sounds Good board for my Rampage. There are like 4 op-amps after the DAC. Since the amp is mono, I took an alligator clip from the ground on the amp input to the common ground of the game and clipped a spare DMM probe to the amp input signal line. All I had to do was to probe the output of the DAC and the analog I/O lines of the individual op-amps. Low and behold the second op-amp was getting the input, but no output. Quick socket and new chip and the game is back to 100%. I hope this will help others trouble shoot audio problems in the future.
 

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You can buy a test amplifier already built for cheap at Radio Shack:

http://www.radioshack.com/product/index.jsp?productId=2062620

Item # 277-1008 Mini-amplifier & speaker. operates on either a 9 volt battery or ac adapter. Just get a patch cord with a miniature plug on one end and alligator clips on the other end.

BTW, a test amplifier like the Radio Shack one and like what you've built is known as a "signal tracer" piece of test equipment. I also own a vintage 1950's Heathkit tube-powered signal tracer i use in testing old tube radios and amplifiers.
 
..and the box is cool to boot.

I can tell you took pride in the build. Nice "case" and a clean layout. No wires running everywhere.
 
Sure, you could just go out and buy a "cheap" radio shack p.o.s. and give another $14.99 to china that's only gonna break in a week. Or you could probably build this in 15 min on a protoboard and stuff you have lying around the shop anyways. I built this for my guitar. It just happens to double as my signal tracer. Quality... Top Notch, Craftsmanship... Great, Reliability... A+, Repairable... absolutely, MADE IN THE USA... a definite YES!!!
 
Cool! What kind of guitar(s) do you have? I'm a very casual player and self taught, but I really wanna take lessons somewhere.
 
Cool! What kind of guitar(s) do you have? I'm a very casual player and self taught, but I really wanna take lessons somewhere.

Great to hear that, I too am a casual player. It's amazing what lives we lead outside of the game community. I have 2 Ibanez guitars. An SZ320EX (my favorite) and a SA260FM. Guitar really relaxes me. I may not be a great player, but I have fun. My only regret is not starting sooner. Like I always say, "Growing old is mandatory, Growing up is optional. Play often."
 
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