Luxman 590AX II Break-In

@celtic66 

I use a pair of Analysis Big Silver Oval.

@jeffreyw

if the speakers are fairly new you can expect better bass from them as they accumulate hours- ~ 200 + or so and the bass will peak. also if new try playing some music with powerful bass for 24 hours continuously to help break them in much like REL recommends for subwoofer break in.

also- are you following the manual for speaker positioning? this includes maximum stand height of 24" so that the bass is reinforced by the floor and the treble becomes smoother when the tweeters are lower than ear level- this is by design and they need to be closer to the floor than usual.

the distance from rear wall, and port plug options are also important-. try to give them some distance to the rear wall and remove any port plugs - again according to the manual for distance from the wall and port plug options.

another thing to adjust is toe angle.  the LS50s like to be aimed straight ahead, not aimed at your ears.

finally the quality of the stands, feet and interface to the speakers are all important.  good quality solid, mass filled (e.g. Skylan, Sound Anchors) firmly spiked to the floor and using the KEF supplied rubber "feet" on the speakers help to make the bass more solid.  the effect that a quality stand has on the bass is often overlooked until you hear it, then you are convinced.  

peace and good luck.

I think the OP has KEF Reference 1, not LS50s. 

@avanti1960 

I am using the kef stands with Iso Acoustics Gaias. Been experimenting with speaker placement and have made slight improvements.

@jeffreyw I owned the Luxman 590AXII for about a year. I would definitely rank it as my top 5 all-time best amps I have owned. I tried it with three brands of speakers -- Sonus Faber Olympica II, Kef Reference 1, and Harbeth SHL5+. Out of the three, the KEF was my least favorite pairing. It was sterile, boring, and lacked the midrange warmth which was, and is, very important to me. I was smiling when I read your OP because I could totally relate.

Speaking from experience, it was the lack of midrange warmth (you can call it luscious) that eventually made me sell my Luxman. To be honest, if you don’t hear it after 175 hours, I don’t think there will be a drastic improvement as you rack up more hours. As someone mentioned, the amp is very neutral with just a hint of sweetness at the top end. Many people love this aspect of the 590AXII but it’s not everyone’s cup of tea if you ask me.

I sold my Luxman and bought an Audio Hungary Qualiton a50i which provided that beautiful, holographic, and lush midrange that good tubes can provide. For me, the Qualiton was a better match for my sonic preferences. I did lose a bit of bass slam but the Qualiton made up for this slight deficiency by doing almost everything else better than the Luxman.

I recently sold the Qualiton and bought an Aavik U-280. I was very skeptical of class D, but this amp IMO took the best attributes of the Luxman and Qualiton and combined them into a single package. It has the lush, holographic, warm midrange of the Qualiton, but it exceeds the Luxman in terms of detail retrieval, pitch black background, instrument separation, and, most importantly, has bass to die for. For the first time in my audio journey, I don’t miss having tubes in my system.