Hi Moises,
Thank you for your review, very impressive. You compared the AKSA to a SEP amp, my favorite topology - with some reservations - but a very valid test and precisely what I had in mind during the development of the AKSA. I really like the SET sound, however, having heard a Cary 805 using the 845 tube about ten years ago, and this was something I strived to emulate.
Of course, you have identified the area of deficiency with a tube amp - the bass. This is even apparent on a Cary - there is just not the power and definition unless the speakers are up around 96dB/watt/metre to give that realistic thump. As it happens, such a bass driver is necessarily low Q, with not too low an fs (such as the Audax 15" which is Q of 0.23, Fs of around 28Hz for 96 dB) and these sorts of drivers, all other things being equal, do not deliver the punchy bass of higher Q speakers.
You spoke of resolution, musicality and bass, but not imaging. This is a huge obssession of mine. There must be palpable 'being there' type imaging, and it's something I really strive for. I would be interested in your take on this; the SEP imaging is generally not so deep as the SET, all other things being equal, so maybe it was level pegging.
There is a huge step up with the Nirvana in the area of bass and resolution. This detracts to some extent from the tube sound regrettably, but it seems part of the tube magic is in fact a loss of resolution. This is hard to tolerate, and might raise a few eyebrows, but I do believe that the tube sound often disguises a loss of micro-detail.
You think the Nirvana is good; you should hear the Nirvana Plus!! The step up is even higher........
Thank you for your great post,
Cheers,
Hugh
