Yes, don't blame Nuforce. If it doesn't sound good, it is the other equipment's fault

Seriously, I urge everyone to read Chris Martens's review where he mentioned about the need to be careful with matching the rest of your system with Nuforce. Similary other reviews have mentioned this important point too.
Which cap are you talking about? Don't mess with anything until you email support@nuforce.com. Work with us to confirm it before you do anything.
If you're referring to the big yellow cap across the speaker terminals, don't remove it. Some people claimed that it makes the system sounded better. We concluded that it is not true. Keep the yellow cap and try to tweak other part of your system.