crown xls 2502

Hello, so, for the time being (until I can afford a miniDSP) I'm running a Topping DX7 Pro to act as preamp for my Crown XLS 2502 (which is powering my subs) via balanced XLR, while also using the RCA output to my powered speakers. The balanced XLR output on the Topping is rated at 4 vrms...

I'm currently running my Elac dbr from a 50w Audiolab 6000a. It sounds ok but I feel like the speaker is struggling to play bass notes properly so I wanted to try out a more powerful amp. My budget is around £500 (less is, of course, definitely better). My current options are: AUDIOPHONICS...