Hi everyone, I have a question about hooking up additional speakers for achieving not only more volume but also a unique tone. This quest started out simple- I was playing a rehearsal two weeks ago with my Ampeg SVT 3 Pro through a SWR Triad when my Ampeg suddenly stopped working and the clip/mute light stuck on (I'm hoping it's just a protection circuit thing, I'm open for suggestions if anyone knows what this might be!) I went to Guitar Center and decided on purchasing a GK MB210 500 watt 210 combo as opposed to replacing the head... I figured once I get the SVT going I can add the two rigs together. Well, in the meantime I tried hooking up two combos together to see if I could achieve a unique sound combination- my other combo is a Kustom KBA100 15" 100 watt combo. I read in the tech post about how combos that aren't matched in volume don't work well together because the lesser rig does too little to the sound, and I gathered from the article that I'd be better off matching the Triad with the MB210 because of their similar watt ratings (400 and 350/internal respectively). I tried using the Kustom the other day via an XLR to 1/4" cord going from the direct out of the MB210 to the input of the Kustom- Volume was way too low. Same story with the effect send, I'm still about to try the DI box next to see if it boosts the output signal back up to a workable level. So, here's the questions:
1. Best way to hook up the combos? DI? A/B box? Small mixer? Or is it best not to?
2. The Ext. Speaker jack- I NEVER
used that on anything since I know I can really damage stuff with it's power- that being noted, my Kustom 100 has a way to unplug the internal speaker from the back (it allows you to remove it from the input to effectively cut it off). I believe this is an 8 ohm load- could I use my Kustom as an External Speaker instead of a Combo if I unplugged the cable and plugged it into the MB210?
3. The Triad cab is a 4 ohm load, so this can't be used as my ext. speaker, right? Plus, since its rated for 400 watts and the 210 puts out 150@8 ohms, I can't use this for an external due to the inbalance of ohms and watts... right?
Well, thanks for any tech help in advance! To pre-answer why I want to get the combos together in the first place, I'd kinda like to keep the 15" in for the Low B stuff and presence while tuning the 2X10 up for a high/high mid range sound for a good, punchy balance.
Combining speakers and/or combos... 
