This summer we have an outdoor gig scheduled in a fairly open area and we don't run the bass through our PA. My normal rig is pretty basic, an Ampeg BA-210v2 and it does everything I need for our regular gigs (pun not intended). The BA210 can't use the full 450w without a cab. We're a 6 piece with a vocalist, keys, 2 guitars, drums, congas/perc., and bass. We play classic rock, R&B, and some prog rock (so shaking the room is not a requirement).
My practice and BU amp is a BA-115v2. So I was wondering if maybe using the two amps together (a/b switch, ???) might be a solution for a bigger sound. The GAS side likes finding a matching 2x10 cab to complete my stage rig. The reality side says the outdoor gigs are pretty rare and it's probably not critical.
Thoughts...
Best Solution:
Running two 210 cabs is the right and most expensive choice and gives you a modular set-up where you can take what you need when you need it, but not lug along unneeded weight when you it's not necessary. However, you may be able to take advantage of the 115 you already have.
A possible solution Using speaker connections:
***NOTE*** After writing the info below on using speaker connections I checked on your BA115 and there is no access to the speaker or a jack to hook up to the speaker, so it's not really a moot point for you. I'd suggest you skip to the section dealing with running a slave amp.****
If your 115 combo hooks up the amp from the combo with a jack to the speakers, you may be able to unplug that speaker from the jack and plug it into your 210. You'll probably need a 1/4" dual female adapter because the cord coming from the speaker cabinet is usually too short to plug into anything else. So plug the short speaker cord into one of the female ends of the adapter and a longer (but not excessively long) speaker cord into the other female end of the adapter, finally plugging the lengthened connection into the output of your BA210 amp. Do NOT use an instrument cord for this connection, if MUST be a speaker cord! That will put a 4Ω load on your amp and the full 450-watts to be split equally between the two cabs. A 450-watt 115+210 rig should do the job just fine just about anywhere.
Another solution running the 115 as a slave amp:
Another option would be to slave your 115 to your 210. This method sends the preamp signal from your master amp (RB210) into the effects-in/return of your slave amp. This bypasses the preamp in the slave amp and sends the preamp signal from the master amp directly to the power section of the slave amp. When you hook up a slave amp to the master amp, every EQ change you make is carried through to the slave amp, but volume changes are not. So after adjusting the volume on each to the blend of 210/115 you want, if you change the volume on the master, you'll also have to change the volume on the slave to maintain the blend you want.
You can set that up by running an "instrument cord" from the effects-out/send of the master amp (RB210) to the effects-in/return of the slave amp (115). That will send the preamp signal from your RB210 to the power section of the 115. With some amps you will need to run a "Y" cord on that connection so you can send that effects-out signal not only out to the slave amp, but also back into the effects-in of the RB2105. On some amps if you don't run a line from the effects/out to the effects-in, it will work fine without running a line back into the master amp because it's designed not to break that original preamp signal unless there's a plug in the effects-return/in jack. On others you have to run a cord back into the effects-return/in of the master amp to complete the effects loop so the master amp gets the same signal back that it's sending to the slave...afraid it's just trial and error to find which way yours works.
When running a slave amp that's actually two combos, you are limited to whatever the amount of power is that those combos put out to their internal speakers on their own. It does NOT influence the ohms load on the master or slave amp at all. Be aware also that your BA-115v2 amp will put out a max of 150-watts as-is while your RB210 will put out a max of 250-watts at 8Ω. So your BA-115 is not capable of running as loud as your 210, but it still should be enough. In my opinion that's not as good as running two 210's when needed, but it is a LOT less expensive solution until you can afford to get a 210 extension speaker for your RB210.
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