strap multiple amps?
Depends on the design of the amp.
1. An ordinary 1 channel amplifier may have 1 channel inside the chassis.
2. An ordinary 1 channel amplifier may have 2 channels inside the chassis,
but both channels are bridged to work together to form 1 channel of greater
power than the individual channel.
Item 1 above can be bridged or in this case, strapped with another amp
of the same kind if they made provisions to make it easy to do. If no provisions
were made, you have to find a way to invert the signal on one amp.
Item 2 above is not strappable by the common approach because it's already
bridged. There is a very unconventional approach that can allow you to
bridge as many amplifiers as you want, but because the method is so complex
and esoteric, it's not cost effective to implement as you need isolated power sources and you need to isolate the signal input. It's just easier to buy a new
amp vs. trying this crazy methodology.