I don’t have a Helix but I’d be very surprised if it didn’t have a dedicated (XLR) DI out for FOH etc & a separate (un)balanced line out for driving a power amp or just going direct into a bass or guitar amp probably in the form of either a TS (unbalanced) or TRS (balanced) jack socket out .. probably with separate volume controls, I haven’t read the manual though lol
As far as power amps .. as long as your Helix sends a strong enough signal (line level) most power amps will work but how much dya wanna spend ?
I’m actually selling a very powerful, high quality power amp that I think will really make your super twin shine .. it’s worth a look as it’s a Lab Gruppen but there are loads of power amps out there (cheap to really expensive) ... time to do some research lol ... you can also use most bass amps that have a ‘return’ or ‘power amp in’ socket which will bypass the amp’s preamp (as long as it’s a serial effects loop) ...