Pass X 250.8 or Pass 30.8 question?

Help me understand what would be the better amp for my situation. I know the obvious differences, One is a low wattage class A amp. The other being basically the opposite.

My setup for one of these amps is : Martin Logan Montis speakers(91db). Source components- VPI scout and lossless files through a Mac Mini through a Cambridge Azur 851D DAC.

My room is pretty lively. I don't need a lot of volume to play music. I currently have a Parasound Halo Integrated. I would say that the volume never exceeds 40% of the volume knob. If your familiar with the Parasound Halo....The volume knob is usually between 9-10 o'clock.

I need some opinions....Am I better off with a lower wattage amp like the 30.8......or would huge power like the 250.8 ( 500/4ohms) serve me better even though my speakers are fairly easy to drive and my room isn't unusually big.

I don't pretend to be an expert in home if these are stupid questions I apologize in advance. However any and all insight would be greatly appreciated. 

Also- I would really appreciate any other Pass .8 series owners to chime in with their insight and opinions.

Thanks in advance,


I have some relevant experience. I own a pair of Summit Xs that I was driving with a Pass XA 30.8 and they sounded great, but due to the speaker’s specs I wanted to see what they would sound like with a muscle amp. So I bought a D’Agostino Classic Stereo amp (300 watts into 8 ohm, 600 into 4 ohm) and hooked it up.

The improvement was pretty significant. The sound suddenly had greater clarity and the music just held my attention to a much greater degree than with the XA 30.8.

The D’Agostino is not a Pass amp, so I can’t say that you would have the same experience with the Pass X series, but my advice is to go with an X.8 series amp. The MLs really do like the extra power and the doubling down.

Also check out this thread:

Whitecamaross has listened to many amps first through his ML Montis then he upgraded to ML 15As, and before he bought a pair of Pass Xs 150s, his favorites were first McIntosh tube amps then Pass X.8 series.
I would think that you would be better off with the X250.8 because according to Stereophile, these speakers are no easy load for an amplifier. Here is the full measurements page from that review:

Here is an excerpt:

I estimated the Montis's B-weighted voltage sensitivity as 88.7dB(B)/2.83V/m, which is higher than average but lower than the specified 91dB. As with other MartinLogan electrostatic loudspeakers, the Montis's impedance drops to a very low value at the top of the audioband. The Montis is specified as having an impedance of 0.52 ohm at 20kHz. My measurement (fig.1), taken with an Audio Precision System One, gave a figure of 0.7 ohm at 20kHz, but this included 15' of speaker cable. Repeating the measurement using the DRA Labs MLSSA system, which compensates for the speaker-cable impedance, gave a figure of 0.55 ohm at 20kHz. Either way, that this speaker is a difficult load for the partnering amplifier to drive is compounded by the high electrical phase angle, and ameliorated only by the fact that music rarely has high levels of energy in the top octaves.


Aside from the power rating, the sonic character of these two Pass amps is also different. The class A amp is a bit "softer", with less sharp transients, and perhaps a bit more "romantic" sounding. Not meant in terms of a strong coloration, but all amps do have their own sonic signature. The S-series, on the other hand, does sound like it has more muscle instead of the romantic sound, there is more slam, even at low volumes, the transients are sharper. Some say the XAs are great for classical, the Xs for harder music such as rock, jazz etc, but this is by no means a hard and fast rule. I own Pass and would be happy with both amps, although I lean more towards the X series for my own tastes.
Although both would sound good, I would go with the Pass X 250.8.
I think you will like the improved sound presentation and details of the music if that's your style?