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Topics - lam0go

#1
The Newcomer's Forum / Fresh Meat
February 05, 2012, 08:20:43 PM
Hello I'm Levi and I'm an alcoholic, oh wait wrong group. I'm Levi and I'm a noob, that sounds better. I am just getting started in guitar and music in general. A friend is walking me through a Mel Bay book, but I am also interested in how my guitar works. I just bought a broken guitar that I needed to replace the volume dial and now I have an amp that has a bad buzz I want to fix. I think it is considered a Solid State since I don't see any tubes. I looked around on the Internet for a while and this site came up often so I thought I'd join and see if anyone can lend me a hand on my project. I'm an American now living in the Philippines going to school so buying parts isn't easy cause they are hard to find here and I've discovered no one has any idea what I am asking for when I go look. (No Radio Shack)

I am familiar with soldering but anything else dealing with circuitry is new to me. But let me describe my project. The Amp I am sure was manufactured here in the Philippines, so it may not be something standard like a Fender or Marshal amp. The case is broke because something fell on it when it was being moved. It still works but I am going to rebuild the case, and while I am at it hopefully get rid of the buzzing sound. I have an idea where the buzz comes from but would like to run it by someone first if someone wouldn't mind helping me.

Description of the Problem:
A constant buzz when the Amp is on, it gets louder when the volume is turned up, and also quieter when I touch and hold the strings, or the TRS jack. So I think it is a grounding problem. It may be due to the way the amp is built, so when I rebuild the cabinet I am thinking of modifying it. All the circuitry exists on a metal tray, I mean everything. I disconnected the speaker and powered on the amp and I can still here a hum coming from the large power supply, not sure what that is called. I think that same hum is what is being sent through the circuits. The large power supply is bolted on to the same metal tray with out any rubber bushings, metal to metal contact. I am considering mounting it to a new location in the new cabinet I'd like to build, on wood where it can act as a insulator and mount it with rubber bushings, would this help?

Also the amp has a lot or circuitry I don't understand. I looked and studied the amp yesterday for about an hour and have effectively managed to remove two of the circuit boards. (The amp has to sets of inputs, each having there own Low, Mid, High, and Volume knobs, which are fed into another board that also has a Low and High Knobs which then goes to a "Master Volume" knob, then to another board which connects to the speaker and some other things that might be acting as "tubes" from a Tube amp. This lead to a lot of excess wiring in the circuitry which made me think it was picking up lots of interference and since I will only need to use it for one guitar I only used one input circuit and cut the other one and the Mixer part out completely. This new setup works but the buzz is still there. The one circuit board that I am using also has a hot wire fed to it, but no ground, does this seem correct? I have also hooked my guitar up to the final circuit board, eliminating everything else, and used the volume and tone controls on my guitar and this worked, but the buzz is still there. I'm not sure why the input circuit board needs a hot wire, it won't work without it, but the final circuitry doesn't need it.

I hope someone understands and can help me. Thanks.