Whatever you do, do NOT combine the left and right outputs together!!! You'll toast the amp.
If the stereo amp you have doesn't have an internal way to bridge it to mono, you are stuck with a stereo only amp.
If you had two of the same amp, you could run the right channel output of one amp to the right speaker and the left channel output of the other amp to the left speaker, but you won't add any increase in power. I've seen this done numerous times, but IMHO really didn't think it provided any additional sound quality.
If you really want mono amps...buy mono amps.
If the stereo amp you have doesn't have an internal way to bridge it to mono, you are stuck with a stereo only amp.
If you had two of the same amp, you could run the right channel output of one amp to the right speaker and the left channel output of the other amp to the left speaker, but you won't add any increase in power. I've seen this done numerous times, but IMHO really didn't think it provided any additional sound quality.
If you really want mono amps...buy mono amps.