Hi Tabu, your probably aware the the Sasha's while being a great speaker are a pig of a load, if not just read the test measurments Stereophile did on them. esspecially in the lower mid bass, nasty impedance coupled to severe negative phase shift.
The Saha's are effiecent at 91db, so they don't need a lot of watts, 50w-100w solid state will do, but it needs to be an amp that can almost double it's wattage down to 2ohm, which means it needs to be a high current amp.
While tube amps will sound ok, your not going to get what the Sasha's are really capable of doing, esspecially in the bass and upper bass lower mids.
The Lamm 1.2 mosfet is a better amp for them than the 2.2 tube, but the speaker really want's an amp that can double it's wattage with each halving of impedance load all the way to down 2ohms. And this means an amp that can give more current than even a mosfet amp like the Lamm 1.2 can give.
They really want an amp with bi-polar output devices like the better big Krells, Mark Levinson's etc etc, that can really do the doubling wattage act all the way down to 2ohms.
"Sasha's plot of impedance magnitude and electrical phase (fig.1) reveals the speaker to be a demanding load for the partnering amplifier to drive. Not only does the impedance drop below 4 ohms for most of the lower midrange and upper bass, with a minimum value of 2 ohms at 86Hz, but there is also an amplifier-unfriendly combination of 3 ohms and –43° phase angle at 61Hz." Quote