Pass Then vs. Pass Now

I have slightly more sensitive speakers and when I went looking for my Pass amp, I was between the XA30 and the XA25. Those who had tried both said there was something especially magical about the XA25. (Of course there's always a debate!) I was concerned about the power level but in all honesty, the XA25 is NOT a 25 watt amp and has plenty of power given the very nice ohm-load your speaker presents. Harley Lovegrove of Pearl Acoustics agrees, here.

Then there's this 6moons review that quotes Terry London: "Wanted to share that I just got through submitting my writeup on the Pass Labs XA25. I believe that this might be the best amplifier Nelson and his crew have yet created/built. I own a pair of XA-60.8, a FirstWatt SIT 2 and have had in my system an XA30.8. The XA25 does color, tonality, spatial qualities, bass control and overall macrodynamics different and better for my taste than these other wonderful amplifiers. I still cannot believe that I'm not listening to a great tube SET were it not for how quiet, quick and dynamic the XA25 presents the music."

Your speakers sound easy enough to drive for the XA 25 -- as Stereophile put it, " Its sensitivity is specified as 90dB/2.83V/m—rather high for a small monitor speaker. The impedance is given as 8 ohms—a "very flat" 8 ohms, according to John, and never dropping below 7.4 ohms."

Threshold made fabulous gear, but a 400A would be >40 years old now.  If it hasn't been updated, you should definitely include the cost of having it gone through, and at the very least having the power supply & other electrolytic caps replaced.

It will still be less expensive than a Pass or First Watt amp, but you get great sound at a discount.  If you have the budget, Pass is still going to be your safest bet, though. 

Nelson has always been clear that he knows we all have different sound priorities.  He started FW as a venue to experiment with different output devices, and optimize their unique sound signatures.  That's why FW doesn't have the traditional pricing hierarchy found at most amp makers.  While a fascinating concept, it puts more of an onus on the buyer to choose their own favorite "sound".

Coda S5.5 could be strong alternative in class A contenders. Threshold is gone, and while Nelson Pass, founder of Threshold, has been producing amplifiers under his own name for some years now, other former Threshold employees are also designing and manufacturing power amps. Their company is Coda Technologies, and their amplifiers are completely up to date in terms of parts quality and circuit design. 

XA 25 is a very pleasant sound with good bass control. Xa30.8 is double the weight of the XA25! It’s very rare to hear someone say they they don’t like the sound. Tastes do vary.

I think the first watt stuff will lack reserve power.  If you don't listen very loud probably OK with excellent sound.

I saw a completely rebuilt Threshold a while back.  $2500.  Demo pass units will start around 4000.

i have had the xa25 along with an int150 (x150.5 with pre front end) and also xa30.5 - have bought the xa25, sold it, bought it back, sold it again through speaker evolutions...

all three are truly excellent but of course, they sound different, do different things well

xa30.5 sweetest of the three in the treble and upper mids, most tube like, if you will -- with excellent tonal density and very good bass control, and ever so slightly softened transients

xa25 is less sweet, more ’straight wire with gain’ in the treble, but still tonally dense, and slightly better bass control, sounds faster more like an x series, than xa

int150/x150.5 similar to the xa25 in treble extension, tonally a bit less dense/saturated, tremendous bass impact and control, mids slightly leaner (just slightly), and of course, a notch greater headroom

i think the differences above capture the essence between the xa25 (which i consider a middle ground between x and xa amps for reasons enumerated above), and what would be consider typical xa vs x series amp’s sound

basis for my commentary is driving the following -- spendor sp100 r2, harbeth mon 40.3/40.2, magnepan 1.7i/3.7i and most recently, laufer technik notes