Are any passive (or active – unlikely) components used in the 3.5mm mini stereo headphone (TRS) plug to RCA audio plug converter cables, such as this one ?
Asking because, during a quick search I came accross some DIY cable post, where a poster commented that they find the audio volume to be extremely low when using such a cable, indicating serious attenuation.
For line-in/line-out (on PC), I found the following Wikipedia entry that talk of the electrical characteristics, but nothing (so far) for RCA audio connectors and the 3.5" mini (TRS) headphone plug.
Also found this interesting post, but it is in reference to RCA to SPDIF conversion (chain), but still not much helpful with respect to my question.
Best Answer
No, these cables are simply conductors with different connectors. There should be no difference if both sides of the cable had the same type of connectors or not, barring any manufacturing defects or low grade parts. Cheaper quality cables sound worse, for obvious reasons (Pre-digital audio).
The biggest case of attenuation as it may be, is different audio signal levels. RCA cables are often used for Phono Level signals, while TRS phone plugs are used at Line Level signals. Line Level signals are about 1v, which is ten times what Phono level uses. Mixing a Phone Level output with a Line Level input, and you will get a very quiet sound. Mix Line Level output with Phono Level input, you will get clipping and distortion as it is overdriven. Same reason a passive microphone can't be heard well on a standard input, without amplification.