[jbd]

I just built and tested my first cmoy using tutorial from tangentsoft.net with all the recommended components. When I tested it with an ipod and the KSC-75s, the sound is a bit noisy and clips at medium volumes. Any idea why? Should I go ahead and add the R5 resistors?

Here are pics of the circuit board:

 

[fortney]

There is a ton of info here and at Headwize re the famous CMoy amp. I

n you case I would start by checking the actual voltage of your power supply if you are using battery power.

f

 

[kanamin]

I was going to say you don't have enough voltage because my cmoy does that when my 9 (ok it's 8.4, 7 nimh cells) volt dies but you're already using two. If fortney's suggestion reveals no problem, try new batteries. Or perhaps you're using the wrong resistors somewhere, check them all (psu I'm guessing, I don't feel like looking up the values right now and reading yours XD). Wait, it appears you've got the 9 volts wired in parallel if I'm not mistaken, try them in series (i.e. wire the + of one and the - of the other together and use the other + and - to hook up to board, as if both were one battery, sorry if I'm just stating the obvious, I'm just trying to be thorough), if in parallel, all you're doing is doubling the available current and not voltage.

EDIT: Also, what's that resistor on one of the leads going to the switch for? I'd assume the LED but I don't see one.
EDIT x2: Nvm, saw the LED, it's a bit hidden.

 

[TzeYang]

hmmm pics are not loading.

Secondly, how does clipping sounds like? i've never heard one so i don't really know.

 

[kanamin]

Quote:

Originally Posted by TzeYang /img/forum/go_quote.gif hmmm pics are not loading. Secondly, how does clipping sounds like? i've never heard one so i don't really know.

Err, I'd say bad distortion that gets worse with more intense or louder sounds. Listen to Sleater-Kinney's "The Woods", tons of intentional clipping there XD

 

[Pars]

It looks from the pic that you have the batteries wired in parallel? If you are going to use 2, I would put them in series instead to give a higher voltage.

 

[achina]

Can you take a picture of the bottom of your board? It doesn't look like the power supply caps are doing anything. They don't look like they are connected to ground.

 

[Pars]

Quote:

Originally Posted by achina /img/forum/go_quote.gif Can you take a picture of the bottom of your board? It doesn't look like the power supply caps are doing anything. They don't look like they are connected to ground.

Good eyes... looks like he's off a row on the bottom leads of the electros... they should be in the same row as the jumpers to ground.

 

[jbd]

I see where I've messed up with the caps. Thanks for the help guys.

 

[kanamin]

Quote:

Originally Posted by Pars /img/forum/go_quote.gif It looks from the pic that you have the batteries wired in parallel? If you are going to use 2, I would put them in series instead to give a higher voltage.

That's what I said, lol.