I recently finished building the crack without speedball, and after some testing I think that there's a ground loop somewhere. When the amp is plugged into my onboard audio, there is noise that sounds a bit like electrical interference; the noise gets louder as the volume knob is turned up, and gains a high pitched body when I move my mouse. If necessary, I can try record how it sounds at high volumes. I also plugged it into the front of my O2/ODAC and had the same results.
I tested the amp with other sources (my laptop and phone) and the noise was not present. These devices were in the same area as my computer. I have tried unplugging a few things from both the mobo and the power strips that the crack is connected to. I've visually inspected all the joints but have not reflowed them.
Today I bought a ground loop isolator (onboard line out > isolator > 3.5 to RCAs > crack) and immediately the noise issues were gone entirely, even when at absurdly high volumes - there's only the expected faint hiss now. I've been listening to it for a few hours and it sounds great, no crackling or popping or anything. (... Although I did get worried because I heard popping at one point and didn't realise I was listening to a vinyl recording. Oops.)
- Do I have an actual solution? Or should I just reflow the joints even though they look okay? I haven't done this yet because I wanted to avoid inadvertently overheating things.
- How likely is it that it's not actually a ground loop with the computer and there's actually something wrong with the joints?
- Does anyone know if the average ground loop isolator can adversely affect sound quality? I bought one from Jaycar.
Thanks in advance. Sorry if there's any entirely useless info in here, I secretly have no idea what I'm doing yet and just getting started on DIY audio.