Running Ampeg Portaflex in Parallel?

campisland · #1 06-28-2011, 01:47 PM

Hello fellow Portaflex enthusiasts!
I am posting to inquire as to whether anybody has ever run an ampeg portaflex parallel with a second cab. i'm thinking of adding another 15 inch cab, maybe another ampeg or something to share the load and ideally get some more low end out of the head. i play a lot of basement shows where everything is very DIY and unmic-ed and the band i am in is just bass and drums so i've got to fill the room.

i've got a portaflex b15n. my brother is an electrical engineer so he can work out the wiring since the original cab doesn't have a jack for parallel wiring.

i know it has an external speaker jack, but would that handle the sound in the same way? come to think of it, i remember thinking that the external speaker jack disables the original cab, but i definitely could be wrong there.

any help is much appreciated!
thanks!

BassmanPaul · #2 06-28-2011, 01:52 PM

Read the manual. What does it say about adding an extension cabinet? If nothing then it can't be done safely.

GeneralElectric · #3 06-28-2011, 01:56 PM

I had a B15 briefly and currently own a B18. The external speaker jack didn't disable the original speaker.

beans-on-toast · #4 06-28-2011, 02:01 PM

You are on the right track. It's as simple as plugging in your extension cabinet into the ext speaker jack at the back of the amp. Use a speaker cable, not an instrument cable. The extension cabinet should be rated at 8 ohms, just like the main cab, to properly match impedances.

Because of the wiring, the main cab normally needs to be plugged in with the 4-pin connector for the extension cab to function. Some amps have this "feature" disabled because it isn't too safe if you have an early model to keep it stock.

coreyfyfe · #5 06-28-2011, 02:03 PM

Your amp should have both extension speaker and extension amp jacks on the back. Plugging into the extension speaker jack should not cut off signal to the other speaker and would be the proper way to hook up a second cab.

campisland · #6 06-28-2011, 02:38 PM

Ah ok great so it is possible,
Does anyone have any experience doing it? As in, how does the head handle it?

pgk · #7 06-28-2011, 02:53 PM

make sure the extension cab is 8 ohms ONLY and you'll be sitting pretty. an extension 8ohm and your onboard 8ohm will give you a 4ohm total load. your b15n can handle that just fine

campisland · #8 06-28-2011, 02:54 PM

great thanks so much everyone!