Ok, got the amp set up and playing. I can definitely can hear the smoothness in the mids and treble, almost like a soft roundness in the sound that my SS amp hits a bit sharper, but it's soft in the mid to low bass, very soft by comparison. I can turn the volume up quite loud without getting any kind of listening fatigue - it is very consistently sweet and polite. By comparison, my SS amp sounds quite nice at low and mid volumes, but gets a bit too aggressive sounding when you crank it up. Clear, clean, but aggressive.
I was worried that 1.7 watts wouldn't be enough. It is probably a bit low on headroom, but does play plenty loud. When things get a little complex, I may be hearing some distortion, but I'm not sure - and that may be because I'm running them pretty hard to get the right volume on my ~97db 1W/1M speakers. I'll have to A/B them a few times with my Sugden A21 amp to get a better feel for the difference.
I wonder if an iron upgrade would firm up the lower registers? I'm sure switching to a 2A3 would help in that regard, but I wonder if upgrading to the EXO-03/40mA and EXO-45 or TFA-2004 would deliver the snap I'm looking for. In any case, I can definitely see why people are so impressed by the midrange and treble on a 45, and why they say the bass is a bit polite or reserved. Just thought I would share my immediate impressions.
