Bill is correct, but of course some "tops" with DSP have a monitor setting or even provide a high impedance input suggesting that guitar/bass is allowed or even expected, but a "top" capable of handling a bass at volume, without a High Pass Filter is both expensive and rare.
I would use your Ampeg Pre-Amp pedal into a lightweight (compared to your EBS) head into a good cabinet. I am not going to recommend any particular amp or cab, but the main difference between amps is the Pre-Amp. As you have the Ampeg, look for an amp with a good power output with the ability to bypass the front end and input to directly to the power amplifier. As for cabinet, look for n uncoloured cab (the colour is in the Pre-Amp).
The main thing about a PA top, such as the QSC 12.2 is that it has a decent crossover, compression driver and horn. Very few bass cabinets have this, so even those with tweeters are a significant compromise. Also avoid cabinets with adjustable tweeter level. This suggests a lack of confidence in the design. Your bass and preamp can reduce the treble, so why put an attenuator on the cabinet?