Homemade headphone amp introducing hiss

[NaOH]

I didn't solder in the potentio meter to control the gain. So it's maxed out right now, could that be the answer? (Sorry, I think i lost it so just making sure before I order one, I guess I can just put some resisters at the output.....)

 

[biggestmuff]

Any deviation from the schematic could cause problems on the circuit. Add the potentiometer, double-check all values and tolerances of the other components, then check all of your solder points.

What project is it?

Good luck and have fun!

 

[Modelworks]

Originally posted by: NaOH
I didn't solder in the potentio meter to control the gain. So it's maxed out right now, could that be the answer? (Sorry, I think i lost it so just making sure before I order one, I guess I can just put some resisters at the output.....)

You need the resistance at the input.
Otherwise you will cause clipping and distortion whenever you feed it an input signal that is too high. Putting the resistance at the output would be like having a singer shout in your ear while your wearing ear plugs.

 

[Born2bwire]

Does the amp hiss when nothing is connected to it? If that is the case than adding a volume pot won't help since the hiss is inherent in the amp and not the input signal.