Pass labs for Sasha's

Hi Stan.
From 70hz to 250hz the Sasha's have a very heavy current demand on an amp, they are 2ohm and have a -45 degree phase angle at 70hz.

So an amp has to maintain god current delivery to get the "very best out of them", this means amps that can "almost" keep doubling their wattage for each halving of impedance load 8ohms down 4ohms down to 2ohms. They are efficient at 91db so the amp can be a 50watter into 8ohms, so long as it keeps doubling down to 2ohms.
Like the old ML2 monoblocks they were only 25watts but I bet they would of sounded magnificent on these Sasha's

EG:
8ohms---- 150watts
4ohms---- 300watts
2ohms---- 600watts

These types of amps will extract the very best from the Sasha's. This type of amps will be BJT (bi-polar) output stages, as no Mosfets will do the doubling act like a BJT amps can, and definitely no tube amp can.

Cheers George

I'm trying to determine if the xa 100.5 will do the job or do I need to step up to the 160.5. The speaker have their duties split between music and movies.

They are both Mosfet Stan, this is what the Stereophile bench tests say about XA160 which is also Mosfet.

"The actual output power at clipping 118W into 8 ohms, 59W into 4 ohms, and 29W into 2 ohms.
Combinations of low-impedance speakers and large rooms should be avoided with the XA160."

As you can see, no doubling at all down to 2ohm. And this is what your speakers demand to sound their best.

Cheers George

Stan,

Your question of will the XA-100.5 do the job needs to be clarified. How big is your room? What type of music do you listen to? How loud do you like to listen? All will impact what will meet your needs and satisfy you.

While I'm schooled and licensed as an engineer, I gave up explaining things scientifically quite some time ago (not that there's anything wrong with that). I prefer to explain how equipment sounds. If someone asks - circuit design, component selection, circuit board topology, power supplies & filtering, component configuration, dampening factor, slew rates etc. can be discussed. I believe it's simpler and easier to describe what works well and how a component sounds.

George is spot on referencing an amplifier needing to be able to supply power into a low impedance load. This is especially critical for amplifiers of (relatively) lower power output. However if an amplifier has a (relatively) higher power output, say 100 watts instead of 30, it can still provide adequate power (current) for low impedance loads even though it doesn't quite double it's output current.

While the Pass 30.5 suffered reproducing dynamics, it never embarrassed itself. It simply wasn't as convincing in a comparison to a live performance.

If listening to the 100.5 and 160.5 with Sashas isn't possible, I'm confident to say the 100.5's, even the most demanding music (anything with big dynamics) with a moderate sized room and lifelike volume, won't disappoint. The 160.5's will always sound better but upgrading is another story. We got the 200.5's on a deal I couldn't pass by - we intended to purchase the 100.5's.

Hope this helps, TJF.

Thank you