So a couple of data points that you may be able to extrapolate from perhaps. I had this same amp for about 18 months. It sounded incredibly good paired with my DeVore O/96's and wretchedly awful with Klipsch Forte III's. I suspect the triode circuit prefers a high, flat impedance. I'd try for something with 10 ohm or higher nominal impedance. At your budget consider used Altec or LS3/5A with a sub? I'd definitely steer clear of the 4 ohm speakers.
Feedback requested on new speakers to pair with my Luxman MQ88uc tube amp
Just sold my Crites modded Klipsch Chorus 1 speakers. They delivered way above their price point but looking for more bass and imaging. I went down the path of low output tube amps and higher efficiency speakers. I have a budget of + - $3K. I prefer to hear something in person and narrowed my selection to these locally available options:
Fyne 502sp. 92db efficiency. Made in Scotland. Titanium tweeter. 8 ohms. Frequency: 30hz - 34khz. Bass enhancing technology (but don’t they all claim to have that?)
Zu Definition Mk2 101db efficiency, 8 ohms. The active amp in each speaker was removed and now powered with a Leon sub amp. Sean Casey says this works but needs to be set up a certain way and recommends hiring a sound engineer to do the work. Sounds complicated but wiling to do the work if they deliver. These sold for over $10K and can get them for $3K.
Audio Kinesis Jazz. These have a 93db efficiency and go down to 30hz, I believe. These also have a tuning port on the back to control bass tone. I understand, these were designed around an Atma-Sphere 30 watt tube amp so could be a good fit. However, not as well known and could be kind of finicky to set up with the recommended 45* toe in.
Sonus Faber Sonetto VIII - These are the least efficient from the group at 90db. They go down to about 36hz. They are 4 ohm but my Luxman has a 4 ohm tap but wonder about any potential strain on the amp and putting out enough power when needed. These are also the most expensive of my choices but I sense a lot of potential if my amp will work.
I have a larger room for my audio gear but my effective listening area is with speakers set about 9’ apart with listening chair about 9’ in the center. I listen to all genres of rock oriented music from the 60’s to today. I also listen to a lot of jazz and blues. Some other local options may pop up but for now these are my choices. I’m sans speakers now and would like to make a decision fairly soon. Thanks!