Problems with cmoy amp...
Aug 8, 2001 at 8:20 PM Thread Starter Post #1 of 7

source direct

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I am currently building a cmoy, and I have run into a problem.

I have the amp constructed, but the sound I get is very very very quiet ! I am getting very little gain and the ouput is quiter than if I were listening to the cd-player source direct.

Does anyone know what the problem might be, and has anyone ever experienced a similar behavior?
 
Aug 8, 2001 at 10:35 PM Post #2 of 7
I would start by looking at all the solder joints to make sure nothing was missed, or shorted by a solder bridge or similar problem. Then double check your layout to make sure all the parts are were they are suppose to be and of the correct value.
 
Aug 8, 2001 at 10:40 PM Post #3 of 7
are you using a volume pot, or a resistor level switch?

With a resistor level switch, make sure the value of that resistor is reasonably close to the values shown in the cmoy article (use a multimeter, not colour codes)

Otherwise, check the two resistors that set the gain, make sure they are the correct values.

Otherwise, does the amp sound alright other than the volume? is it distorted or are any vocals missing, or does the amp pick up radio signals? if so, its usually a grounding problem, where one of the connections is not connected properly to the ground.
 
Aug 9, 2001 at 2:45 AM Post #4 of 7
It's all still in the breadboard and I haven't implemented the switch yet.

I'm not getting any interference, and the quality seems to be good, but it's just SO quiet.

I also am only testing one channel.

I think that the capacitor I'm using is lame, and might not be the correct specification that cmoy intended. I'm going to order some .1 uF caps tomorrow. We'll see what happens then.
 
Aug 9, 2001 at 8:30 PM Post #5 of 7
Don't worry, we'll get through this. I too am breadboarding my first cmoy, and its gone smoothly except for a volume dependent distortion that I've isolated to the pot. I'm going to resolder the pot leads and see how it goes. Good luck with the amp!

jamf
 
Aug 9, 2001 at 9:20 PM Post #6 of 7
Are you taking any liberties with the specs on some of the components?

Maybe that's my problem.
biggrin.gif
 
Aug 9, 2001 at 9:29 PM Post #7 of 7
Nope, its strictly by the letter. My wild uneducated guess (to my problem) is that its a short due to shabby soldering, unless the pot is bad
frown.gif
. When I incorrectly wired the thing on my first try, the sound was like poorly tuned fm. God, my board looks a mess ( its a surprise I wired it properly!) I don't know what's up about your quiet problem though, sorry.
 

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