# Why do the "LINE OUT" connectors not seem to output audio, but "HEADPHONE JACK" does?

I have a "Clas Ohlson TCD-983WEC CDMP3". It's a cheap "multi-unit" music player bought maybe 10 years ago or longer. I'm using it exclusively for its (cheap) tape player, since my original tape player has sadly stopped working. I'm trying to digitize some old tapes.

I first connected a standard quality audio cable from the "LINE OUT R" on the device to the "LINE IN" (blue) connector on my PC's sound card. No sound whatsoever, regardless of the device/settings in Audacity.

I then switched the audio cable to the "LINE OUT L" on the device. No sound whatsoever, regardless of the device/settings in Audacity.

Finally, in desperation, I connected the audio cable to the "HEADPHONE JACK" on the front of the device, which I would assume is only for connecting a headphone and not for capturing audio... immediately got sound in Audacity, and it even seems to be in stereo!

What could explain this? Why do the actual "LINE OUT" connectors not output any sound signals at all, but the headphone one does, and apparently in stereo on top of it? And is the headphone jack "lesser" somehow? If I use it (and I don't see how I have any choice at this point), am I getting a "lesser" quality audio signal?

• perhaps the standard quality audio cable is not the correct cable to use ... why are you surprised that a stereo headphone jack outputs stereo signals? Jul 10 '21 at 23:47
• Might be worth looking here: en.wikipedia.org/wiki/Line_level
– Mark
Jul 11 '21 at 19:13

Figure 1. The user manual diagram suggests that the line out L/R are (RCA) phono sockets, not 3.5 mm jacks.

Figure 2. Phono to jack adaptor. Image taken from Google image search.

Figure 3. Phono plug dimensions. Image source: HiFi Collective.

The phono plug tip is 0.125" = 3.175 mm. The socket opening is probably just big enough to push a 3.5 mm jack into but the electrical contacts will not line up.

Figure 4. The RCA phono sockets have the signal connection on the inside and ground connection on the outside. Image source: RS components.

With a 3.5 mm jack inserted you might make contact with the signal contact but you won't make contact with the ground.

• The OP probably doesn't want an adapter like the one in your picture, which has a 1/4 inch jack socket (twice the diameter and length of the miniature jack plugs used with most consumer audio equipment and computers.) Jul 11 '21 at 9:56
• Correct. The socket should be "3.5 mm stereo". Jul 11 '21 at 12:25

Same audio cable 3 times? Probably not correct for the line out sockets. I use line out / line in as they connect prior to the amp so less distortion but a lower signal level. Try the correct cable - headphone is stereo and line R line L are each mono.

• I'm not aware of the existence of any other cable of the same plug/size, and I certainly don't own one. But if the headphone one has stereo, what is the point of the separate ones on the back?
– J C
Jul 10 '21 at 23:59
• You need a cable with two mono plugs on one end and a stereo plug on the other. Warning, there are more than one type of mono plugs. (e.g.. RCA and XLR). I found the instruction manual for your music player online but it didn't say which type of plug it uses, and didn't have a picture - only a line drawing that wasn't necessarily to scale. Jul 11 '21 at 0:16
• The most likely guess for a consumer-level device like this is a cable with two phono plugs (or RCA plugs - different names for the same thing) to stereo - but that is only a guess based on no hard evidence. A stereo jack plug in a phono socket is 100% guaranteed not to work. Jul 11 '21 at 0:23
• What did you connect it to?
– Gil
Jul 11 '21 at 2:08
• @Gil Is that question for me? If so, what do you mean?
– J C
Jul 11 '21 at 2:14

I'll focus only on the headphone jack part (because I don't have any experience with the Clas Ohlson TCD-983WEC CDMP3).

Headphone jacks have different configurations (Most of us just don't really pay attention to it)

Figure 1: Difference between mono and stereo headphone jacks (source: snapshot from youtube video

Each section of the jack conveys a different signal usually:

Figure 2: Typical configurations of headphone jacks (source: Filipe M. Cross

From what you see the front part remains more or less the same, and the remaining part is divided. The remaining part is the ground part, so you can connect a stereo headphone to a mono source with no problem (or the opposite).