All my amps have left speaker out??

The suggestions to verify cable connections and integrity are good ones. You have to troubleshoot this type of issue systematically or you will drive yourself crazy. It is highly suspect that all of your amps have the issue on the left channel only. Swap only one set of cables or components at a time.

One last thought, have you completely ruled out the left speaker as the issue? Will it play music at all? If the cable swaps do not solve the issue, hook the left speaker to the right channel using all of the cables that were hooked up to the working channel. It would be highly unusual, but not impossible for the speaker to be the culprit (I.E. a broken connection internal to the speaker), since the issue seems to be coming from one side only. This would be something that I would try only after ruling out cable and connection problems. Good luck

One thing you might want to be very careful about is that the speaker wires at the left speaker end are not touching or any other condition that might be causing a short downstream of the amp on the left side. A long shot but if they amps were swapped in sequentially with that condition staying the same, it could cause the left channel in all three amps to go out.

Yes, it is possible that a preamp or source component could be having a problem with one channel. It is also possible that a cable (interconnect, speaker cable) could be having a problem. Swap one item at a time until you identify the culprit. Changing 3 sets of speakers I would assume that it is NOT the speakers, but best to switch them to different channels just to make sure.

Cheers,
John