Last week I built a Banzai V2 18v CMOY amp. This is my first amp build, and the first headphone amp I've owned. I've been using it for a week without any problems to speak of.
I noticed a phenomenon today at work where I'm getting a pretty pronounced crackling buzz with peaky treble (high-pitched piano notes, etc.) It sounds a bit like a blown speaker, or a driver being over-driven. I noticed it first listening to Copland's Appalachian Spring, which I was playing through the onboard sound on my work iMac.
I've only been able to hear the buzz through my Beyerdynamics DT770's and I can hear it in both channels. It doesn't seem to happen with my Portapros, although I suspect the lack of high-end detail could be the reason.
The weird part is that if I crank the amp to maximum and turn the computer volume down, the crackle goes away. As I decrease the volume on the amplifier, even without increasing the computer volume, the treble starts to break up. It sounds a bit like clipping, however with the more alarming "buzz" that typically means there's something wrong with your speakers.
So basically, it sounds clear and fine (if with a bit of background hiss) at full-volume, but anywhere below seems to cause breaking up and distortion in the pronounced treble. Is it possible that there's something wrong with my op-amp? It's a JRC 2068DD.
