I'm currently driving a pair of refurbished KEF 104/2s with a NAD C370 and decided to see how other amplifiers would sound. Each setup was driven with a Topping D30 DAC and not built-in DACs. I purchased a NAD C368 (80 WPC, hybrid class D amplifier) integrated and found that the low frequency response was similar to the NAD C370 in that it was present, but didn't have much oomph. The upper mid-range and high end sounds far more clear and bright with the C368 compared to the C370, but not fatiguing with these KEFs. This was very evident with dynamic guitar (i.e. Rodrigo y Gabriela). I also demo'ed a Rotel A14 (80 WPC, class A/B) integrated to see if the lack of a powerful low end was due to the amplifiers or speakers, and surprisingly found a much smoother and present low end and mid-range compared to both NAD amps. However, the high end isn't as bright which may be a drawback with the KEFs. The more powerful low end was evident with electronic music (i.e. James Blake) and drum-heavy classic rock. Are these listening impressions consistent with what you'd expect for vintage KEF reference speakers? I've been running the NAD C368 for over a month now so perhaps my ears have gotten used to how clear/bright this amp is, but neither NAD amplifiers seem to drive the KEF woofers as well as the Rotel.