LTA Ultralinear vs Pass Labs XA25

I have the Xa-25 so have researched the threads regarding that.  If your primary music is rock, consensus is go Xa-25.  As far as power goes, your 4 Ohm designed speakers with the Xa's output of 50 Watts class A at 4 Ohms might be a better match.  Room, music and playback volume etc. aside.

Srajan at 6 Moons started reviews on both. Im looking forward to his comparison. 

To add to Wlutke’s comments I would definitely not proceed with the LTA Ultralinear before asking Mr. Salk about the suitability of using an amplifier having a 1.6 ohm output impedance with your particular speakers. My strong suspicion is that the result would be weakness in the bass and mid-bass regions, as a result of the interaction of that output impedance with the speaker’s impedance variations over the frequency range. Especially if the impedance curve of the HT2 is generally similar to that of the HT2-TL, as shown near the middle of this page.

Also, keep in mind that 20 watts is only 3 db more than the 10 watts you are presently finding to be insufficient.

Also, as is the case for most such specs I suspect that the speaker’s 88 db rating is based on an input of 2.83 volts. For the speaker’s 6 ohm specified nominal impedance that corresponds to 86.7 db/1 watt/1 meter. For the 4 ohm impedance the speaker probably has in much of the bass and mid-bass regions, where lots of energy is typically required, it corresponds to only 85 db/1 watt/1 meter. For most listeners 20 watts won’t be sufficient with speakers having such low efficiencies.

Finally, it’s a bit disconcerting that the LTA amp does not have a specified power rating for a 4 ohm load.

BTW, FWIW I’m a very happy user of an XA-25. My speakers are Daedalus Ulysses, which have an extremely flat impedance curve, a 6 ohm nominal impedance, and a specified sensitivity of 97.5 db.  I listen primarily to classical music. 

Good luck, however you decide to proceed.

-- Al