EA stuff does tend to be very transparent, which would likely make it a great platform for a pedal to act as an additional preamp. Small package, lots of tones available between the two... Assuming the Doubler has enough power to keep you satisfied I don't see why it would be a bad idea at all.
Tech 21 VT, VT-Deluxe, Oxford, Leeds, etc. They've all received mostly glowing reviews. Catalinbread SFT for another Ampeg-emulating option. Tronographic Rusty Box for something with a bit more of an aggressive character. Darkglass Electronics Microtubes B7K, Aguilar Tone Hammer, Sadowsky Outboard.... The list goes on and on and on
