On Fri, Jan 06, 2012 at 10:50:12AM -0500, Chris Metzler wrote: Adapters don't normally introduce noise or degradation. But they are often used to connect things that are not compatible anyway, and they tend to fail (bad contacts) after some time. Try to avoid them, they are in general a nuisance. RCA inputs are 'consumer line level' and unbalanced, which is a disadvantage. Line inputs are not meant for guitars, so those people who are complaining get what they ask for. Sound quality is not determined by the connector. But the use of such connectors can indicate 'budget quality'. Very often they are used as a combined mic/line input (mic = XLR, line = TRS). Then it depends: if the line input is just an attenuator feeding the mic input that's not really very good. A real line input does not pass via the mic preamp. No. Guitars are not line level, they produce a much weaker signal and need a preamplifier with a high input impedance. Some sound cards have 1 or 2 inputs that can be switched for use with guitars. Without those you need a DI box. A cable with TRS connectors*can* be balanced, one with TS definitely is not balanced. Any balanced input will accept balanced and unbalanced signals. Yes, unless the line input can be switched to high impedance and has enough sensitivity. As already mentioned, some interfaces have such inputs. But you can't use a standard mic or line input for a guitar. Yes. Normally the DI box is connected to a microphone input. In most cases not, see above. Some other things to consider: Usually you get what you pay for. Quality is not only sound quality, but also construction and reliability, and it has a price. If you are a musician, consider the combination of a simple but good quality soundcard having only balanced line inputs and outputs (even fixed level) with one the many small musician's mixers. These usually have mic and guitar inputs, a headphone output etc. Such a combination is much more flexible than any soundcard. Ciao, -- FA