I once had ProAc EBS in my system in the late 80s. While something like an ARC D76A sounded beautiful, you're right that an amp of that nature didn't yield good bass discipline with EBS. However, the tweeter is ruthlessly revealing of solid state harshness, so only exceedingly clean silicon amps have a chance of being satisfying. In solid state, Electrocompaniet and the McIntosh autoformer-output transistor amps of the past 10 years will do nicely, MC452 and above in the current Mac line.
HOWEVER, in tube amps, OTL is the ticket for this speaker. You need power so it has to be push-pull OTL. I used to power my EBS with Futterman OTL monoblocks. It was a sensational combination with impactful, well-defined and controlled bass. In today's market, I'd consider powering the EBS with Transcendent Audio's "The Beast" monoblocks, or one of the bigger Atmasphere amps.
Phil
HOWEVER, in tube amps, OTL is the ticket for this speaker. You need power so it has to be push-pull OTL. I used to power my EBS with Futterman OTL monoblocks. It was a sensational combination with impactful, well-defined and controlled bass. In today's market, I'd consider powering the EBS with Transcendent Audio's "The Beast" monoblocks, or one of the bigger Atmasphere amps.
Phil