Hey fellas... You ARE aware that these amps are twenty or more years old now and NOT NEW??????? As a result, they'll have bedded in, drifted gawd knows where and if they haven't been serviced, they'll need a good check-over to bring them back on song.. Do this, and you'll probably find that time has removed any differences between them, if there were any in the first place. Choose your speakers with care though, as there's little power available and I don't remember them soft-clipping as gracefully as the Nait 1 did.