grausch
Head-Fier
- Joined
- Oct 2, 2013
- Posts
- 64
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- 15
I'm sure it's not the source. PC to modi 2 uber with toslink, RCA to crack. Unplugging the RCA from the crack doesn't get rid of the noises. At one point, no RCA plugged in made the noise change from hissing to humming at full volume. After "shielding" the RCA to pot wires with aluminum, it's sometimes completely quiet at full volume, and other times scratchy. Definitely different than before adding the aluminum. The general background noises I'm also describing happens at any volume, but doesn't get louder if I turn the volume up.
Honestly, I'm completely confused about it. Sometimes I find a correlation between the noise and something, and then an hour later, they're no longer related. That was the case of the tube heat. At first it seemed like the colder tubes had more noise, now it seems they have less.
I'll do some research into attenuators later on. I'd like to try and solve the noise first, but thanks for the recommendations. I'll keep them in mind.
I have a feeling I'm going to be spending many hours poking connections and resoldering...
I would get a thread going on the Bottlehead site and post some pictures. The guys there are pretty good at the troubleshooting.
I have never had humming, so never needed to investigate potential causes for that. However, here is a helpful ground path check that can eliminate some potential problems (http://bottlehead.com/smf/index.php?topic=4812.0). If everything is properly grounded, you have no ground loop elsewhere and the RCA cables are properly braided / shielded then you should have no hum.
When I had static in my Crack, my first problem was a noisy USB port. Once that was fixed I also had another problem with the soldering at T13. Once that was fixed my amp was dead quiet. With the help of the Bottlehead crew, you should start eliminating problems until you find a solution. Might take a bit of time, but definitely worth it.
If your Modi 2 is running in 24-bit mode, you can decrease the volume on your PC without any loss in sound quality. Look for GUILT-FREE VOLUME ADJUSTMENT here - http://nwavguy.blogspot.lu/2012/04/odac-released.html. If you do not wish to go that route, then the Harrison Labs attentuators are the easiest solution. Just make sure you go for the -12db padding. The smaller values do not make enough of a difference.