Louis- Unless the amp you get has exactly the same gain, you are going to need a gain control at a minimum. Most people who do horizontal bi-amping with different amps use an active crossover to control levels and let each amp work on only their proper part of the signal. You could spend quite bit of money on this, including extra ICs, and so forth. The Y connector is only a small part of the equation. You might be better off finding a better amplifier and selling your EMC. BTW, the bass on the VR4 is impressive with most any amp. I demoed them once with a 70 wpc Berning ZH-70 tube amp and it a modest size room, it drove them very comfortably, with PLENTY of bass and not dry at all, IMO. Not sure what you could get for your EMCs, but even if its only $1K, and you add in $3K and the cost of interconnects AND a crossover, you would close to $5K. At that price, you are into some pretty rarified territory for used amp, and could even get a new, fully modded ZH-270 (if you can wait 6-8 months!). It even has switching for 2 sources, and its own gain. Lots of other great amps would be possibilities if you go that route.