Amplifier specified 4 Ohm into 2 Ohm?

Hemisphere wrote: If you want to run 2 cabs on each amp in bridge mode and they're only seeing 30w amp power each, you could do a lot better by just selling these RCF amps on eBay (where they should fetch more than their watt rating alone would warrant due to 100v line and other features (are any of these critical to you?) and spend whatever you get on a couple of used ~300-1000wpc amps. Even if you need the signal to be split for processing purposes you could pick up 3x 300-400wpc amps and run 2 speakers on each channel.

The amps are mono so there's no bridging involved. Still good advice about selling them on.

Those amps are 100V line mixer amplifiers, that just happen to let you use the pre-transformer low impedance "tap" at 4 Ohm.

OK, curve ball suggestion that might work or might kill you;
Strap* two mono amplifiers together, give one a signal that's out of phase with the other and use the + outputs on each amp as if they were + & - on a single amp. I think you need to 'strap' the earths together too, but you really shouldn't attempt this until someone less out of it than me has spotted the fatal error/omission above...

*Like bridging a stereo amplifier, but without the convenience of a bridge switch (and the knowledge that the magic smoke won't escape). At your own risk etc.

I spent a while trying to get two Kenwoods to party together, but they drew too much DC from my supply for me to want to continue. No magic smoke though.

It was a common trick with car bass amps, some of which were sold with strapping in mind. Nowadays a lot of class-D amplifiers come pre bridged, so not a good idea double-bridging. But for getting some power out of two identical but crappy monoblocs...

Generally not a good idee due to potential for catastrophic fuckup, but essentially it's wiring up a stereo bridged amp from two mono amps.