In the post-LP era, various audio source devices that match home power amplifiers adopt the line (LINE, or AUX) output interface standard, with a typical output impedance of 600Ω and a voltage amplitude of 0.7~1VRMS, such as cassette recorder (TAPE), tuner (TUNER), video recorder (VCR), various laser audio and video players (CD/LD/VCD) and computer sound cards, etc. Therefore, although the power amplifier is equipped with many groups of input ports with different names, their function is only to correspond to the name of the sound source selection switch on the panel. The functions and internal circuits are the same - in this sense , it is possible to take over any group, just put the audio source selection in the position with the same name, and the music player is no exception.

It should be noted that the output port of a portable music player (or mobile phone) needs to directly drive headphones, with lower output impedance (several Ω to tens of Ω) and higher output voltage amplitude (several Ω). VRMS), but it can also be directly connected to each line input interface of the power amplifier. If the volume of the power amplifier is too loud and the adjustment is inconvenient, just reduce the output of the portable device appropriately.

In short, except for the LP and MIC input interfaces that cannot be used on the power amplifier, any other group can be connected.