AMI Amp input question

Hello on my AMI I have the R-2017 monaural amplifier.
On the L-2156 plugin mono pre-amp it has, there is the input RCA plug for the phono arm that works fine.

My question is about the other input it has on the basic chasis of my amp.

When I plug there my mp3 player for example, it sounds great, but that RCA input works also only in un-muted mode (while the turntable is working).

I am thinking to by-pass that issue by un-muting the amp with a switch, when I want to play some mp3's through the jukebox.

I have noticed that when my mp3 is plugged in that second RCA input, the main RCA input of the amp (where the phono goes in) plays in a much lower volume order (so I can't leave it plugged in while my jukebox records are playing).

Another thing I noticed, is that although my mp3 player sounds great through that second input, the jukebox phono sounds lousy and low when connected there!

Why is that? Could any damage be caused by allowing that second RCA plug from the mp3 player be plugged and playing music? why was that 2nd RCA input made in the first place? maybe for a mic?

Just wondering so I don't damage the amp in someway!

Takis, there is no harm in using it this way. That RCA plug is parallel with the output of the preamp and was often used as an output for a booster amp to power large installations.

Your "pod' device is designed for low impedance loads such as headphones. When connected to this amp the pod's low source impedance loads and partially shorts out the output from the preamp.

A more elegant approach is an audio activated switch. These typically have an input for the control signal, in this case the Pod, which controls a relay w/multiple contacts. When the switch senses audio from the Pod it will open the circuit to the mute relay coil and another set of contacts will patch-in the feed from the pod.

Some of my locations have these devices so that if the jukebox is not in use a radio tuner comes on but if the TV input to the sound rack is turned on that signal mutes the radio. This is primarily used for 'big games' where the whole location needs high level audio.

Rob

Hi Rob,
thanks for the help.
I didn't think about a audio activated switch. that sounds brilliant. I will check out to find one.
I was thinking of a manual switch that would cut off the mute line-wire, while at the same time closes the circuit of the rca cable, allowing the audio to go through.
I was also thinking instead of connecting the ipod straight on the amp, to connect a bluetooth reciever first, so i could send music on the jukebox from my mobile phone via BT. (I believe that way would also be safer for the ipod/smart phone.

thank you for the cool advice!
Takis