Adding a cab to a combo

[Tonkacall]

It is doable with minimal rewiring, exactly how much depends on the specifics of your amp. But any time you combine two speaker cabs of the same impedance they combination is going to have either double the impedance (so less volume) or half the impedance (risk of damage to amp) than the original. It depends on whether you wire them in series or parallel.

Additionally if they are mismatched speakers there are risks. If one box is less powerful it becomes a weak link and can blow if you run everything harder. And if the boxes have different characteristics the sound might be inconsistent.

If what you are after is more volume then more speaker area is the way to get that. So you could get a bigger set of speaker boxes and just use the combo as a head.

Or if it has a preamp out you can split the signal there and feed it to a second power amp and cab.

I can't see an ha3500 combo on Hartke's web site, so I can't be more specific.

Good luck.

Thanks, there is a direct out with a pre/post EQ switch and also an effects loop, and i do own a power amp. I might look into this method.

 

[Tonkacall]

You can't. If it's not loud enough it's time for a new rig, and make sure you can drive two 4x10s with it.

The head is removable and can be rack mounted.
This might be a stupid question, do 810 cabs come in 4ohms?

 

[bassmeknik]

The head is removable and can be rack mounted.
This might be a stupid question, do 810 cabs come in 4ohms?

Yes, my fridge (Ampeg 8-10) is 4 ohms.

 

[bassmeknik]

If your combo amp can be easily rack mounted then an 8-10 would seem to be the best choice from what has been commented on here.

Buy a rack case and an 8-10 (used can be had for much less) and swap the head from combo to rack case and back as needed depending on venue size/ needs.
I got my Ampeg 8-10 for 350 on CL physically beat up but sounding good, a rack case should be 40-75 used