CMOY amp help....very quiet.
Apr 14, 2002 at 4:45 AM Thread Starter Post #1 of 8

fyleow

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Im building my first CMOY amp with Tangents tutorial, however im having some problems. The sound coming from the amp is very very soft, even with my player turned all the way up. I have checked the power supply connection and it is supplying the 4.5 v it is supposed to. I have tried adding a second battery but it doesnt boost volume at all. Ive checked resistors and stuff and they appear to be correct. It cant be the amp chip right? Since there is some sound. This is the second one ive soldered together, the first had distorted sound and so i decided to start over from scratch. The previous one was louder but it was still pretty soft.

Any help is appreciated.
 
Apr 14, 2002 at 5:58 AM Post #2 of 8

RMSzero

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Check to see if your volume knob is connected right. In fact, try bypassing the volume knob entirely.

I wouldn't worry about the power too much, undistorted sound indicates that the power supply is fine.
 
Apr 14, 2002 at 6:20 AM Post #4 of 8

JMT

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Check and double check your resistor values with your meter. It may sound redundant, but you would be surprised how easy it is to make an error with those.
 
Apr 14, 2002 at 6:15 PM Post #5 of 8

fyleow

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I have double checked them and they seem to be correct. What are the usual causes of this problem? Maybe the input isnt connected well enough? Since it needs a loud volume to be faintly audible?

Oh and one question, about the input/output jacks how do i know which one is left and right? There are 5 connection points, i think i have them correctly but im not sure.

They are arranged like this 1 3 5
2 4

Im guessing 2 and 4 are left and right....
 
Apr 15, 2002 at 11:58 AM Post #6 of 8

tangent

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Quote:

Im guessing 2 and 4 are left and right....


Don't guess -- test. Hook up a patch cable to the jack, and use your ohm meter to find out which pins on the jack go to which pins on the cable.

A phone type cable has three conductors: tip, ring and sleeve. (The meaning of the names should be clear, if you stare at the plug long enough.) Tip is left channel, ring is right, and sleeve is ground. I've found some equipment that reverses the meaning of tip and ring, but that's a minor issue.

Are you sure the sound is undistorted? If it's sounding thin or a little crackly as you turn the volume knob, you don't have a volume problem. If that's what's happening, it can be oscillation or grounding problems.
 
Apr 15, 2002 at 2:46 PM Post #7 of 8

JMT

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To test your jacks. Go buy a plug from Radio Shack and remove the plastic housing. Plug it into your jack, set your meter to test continuity. Touch one lead to the jack pin, touch the other to the plug. If your meter beeps, then you know what pin goes to what plug lead. Like Tangent said, typically it will be: Tip - L, Ring - R, Sleeve - G.
 
Apr 16, 2002 at 12:14 AM Post #8 of 8

fyleow

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Ok i have tested the jacks and 2 and 4 are the left and right channel, 1 is ground. I dont know if the sound is distorting or not, I havent even added a potentiometer for the volume. Its running at full power and i can barely hear it with my mp3 player turned all the way up.
 

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