cmoy problem

[enzoferrari650]

So i finished my cmoy and decided i'd check if it works without the pot. I plugged in everything and as soon as i touched the battery to the clip, the headphones makes this huge buzz sound. A low frequency buzz thats very loud. I dont think this is supposed to happen. Does anyone know what could be the cause of this? Bad parts maybe?

 

[enzoferrari650]

maybe you should also note that i only have one of the audio capacitors placed. I havnt soldered the other one on yet so theres no right input. Could this be the problem? The buzzing comes out of both channels even tho theres no right input.

 

[enzoferrari650]

Alright now i soldered on both caps but it still does the same thing, only this time its not as loud and as fast. And when I play music into it, I can hear the frequency trying to change but its just high to low frequency buzzes.

 

[enzoferrari650]

I seriously need some immediate help....... has anyone ever had or heard of a same situation? If so, what is the most likely cause of this. I really want to get this darn cmoy working!

 

[enzoferrari650]

help help help help plz someone help. Tangent, any tips? suggestions?

 

[Heady]

I had a buzzing problem with a cmoy once and it was the ground connection between the source plug and socket not making contact. The buzzing was loud. I have no idea if your problem is similar.

Regards.

 

[tangent]

Quote:

A low frequency buzz thats very loud.

Are you using a volume-controlled source, like a portable CD player, and are you using the headphone out jack? Does the buzz still happen when the volume is turned all the way down?

Quote:

I seriously need some immediate help.

You won't go very far in DIY without a bit more patience.

Quote:

it was the ground connection between the source plug and socket not making contact.

Yes. Ground problems are the most common cause of buzzes.

enzoferrari650, are your input and output jacks' ground contacts connected to virtual ground on the amp board?

 

[enzoferrari650]

sry, i'll be more patient. where is the virtual ground on the board? All i did was connect the jacks ground to eachother. Do i just conenct it to the center column?

 

[thrice]

Quote:

Originally Posted by enzoferrari650 sry, i'll be more patient. where is the virtual ground on the board? All i did was connect the jacks ground to eachother. Do i just conenct it to the center column?

Ok you'll need to disconnect them from each other and then wire each of them to virtual ground. If you're using the 0150 board, then virtual ground is the two long bus strips in the center of the board. These strips should be connected at either end with a jumper to tie them together.

 

[enzoferrari650]

hmmm alright. so its working now but only from the left channel. When I disconnect one of the ground wires from the board and leave the other one, theres sounds from both channels but theres a lot of static.

 

[enzoferrari650]

Thanks to you all for helping me. I finally got my cmoy up and running in its tin with no probs. Well except that I fried my ad8620, but i'll just use the opa2134pa for now instead. Too happy to get mad at the ad8620, or rather my stupidity. Heh, well thanks again, i'm gonna make a new thread for my new amp.