Bass is limited by transformer and any of the indirect coupling of the output stages. It's less-likely limited by class of operation.
Any benefit from" same brand" amp/pre-amp??
Is there any benefit from the amp and pre-amp being the same brand??? I am consdering separates, and like the Quad 99 series pre-amp. It does have a matching power amp, model 909, but bass is limited because of the bandwidth limits of its class D design. I have read about and considered an amp called the Odyssey Stratos. It gets very good reviews, but I do not know if it would be compatible with the Quad pre-amp. Thanks