Luxman L-550ax

The 550ax is a beautiful piece, and congrats on snagging one. And from someone who listens to a 25W pure class A amp (First Watt M2) that drives a pair of 4-ohm, 86db pair of Dynaudios with absolutely no problems in a room larger than yours, I think you'll be fine. Yes, others will probably say no way, but you'd be surprised what some amps can do...it's all system dependent and what sounds good to you.

I think you'll be fine. Luxman never posted the complete specs on the L-590 and L-550 amps. Their specs are on the Class A power alone, after that point they change to AB, and put out considerably more power.

The 550ax is actually a pure Class A design, so it does not transition to AB...maxes our at 40W into 4 ohms.

bojack, perhaps you’re correct, but that would seem unusual to me. The L-590AX is also advertised as Class A, 30W/ch into 8 ohms, but transitions out of Class A and produces around 90W/ch, 8 ohms, and something like 160W/ch into 4 ohms. I would expect the 550 to operate in a similar manner.

https://www.luxman.cz/data/test/test-en-l590axii-hifinews.pdf

@enobenetto 

A 15’x20’ room is plenty big enough for floorstanders. No need to limit yourself to only bookshelf speakers 

I agree, get larger more efficient speakers for that room and Amp.

My beloved little Luxman SQ-N150 is rated at 10 wpc at 6 ohms, the goal is to keep the heat low so I can use tubes in my 10' x 10' x 8' high office, my 90 db AR-2ax’s sound great, but no way is 20 wpc enough for inefficient speakers and/or a larger space, certainly not for main system.

I would look for sensitivity of 92 or higher, and make sure the impedance curve does not have difficult dips. 

And, those ’nominal’ 4 ohm speakers dip to 2.6 ohm

• Impedance: Nominal 4 Ohm (min 200Hz / 2.6 Ohm)

@enobenetto - I have the Luxman 590axii. I strongly encourage you to get more sensitive speakers. I’ve experimented with a few insensitive speakers with my Luxman. To make the music really come alive, I feel strongly you’ll benefit with a change of speakers. 

I looked all over hell, there isn’t a single bookcase speaker that I would choose over my AR-2ax’s, which are just shallow enough at 11-1/2" to fit: 

in a bookcase

on a bookcase

on a stand (see KLH photo below)

you can find restored by others, or restore them yourself like I did to my 2 pairs. everything needed is readily available.

https://www.hifishark.com/search?q=ar-2ax

3 way, 10" woofer, separate level controls for tweeter and mid to adjust in your space.

There is also the KLH-5 restored or sold new these days at Crutchfield ....

It comes with a single level control

Both +/- 90db sensitivity, nominal 8 or 6 ohms. Your 20wpc would definitely sound good, the eventual space will determine if you want to upgrade the amp’s power someday.

If you live close enough to 07062 we could hook up my AR-2ax’s at your place, or your amp at my place, better yet, both! 

85dB / 4ohm is likely rated at 2.83V  equivalent to 2W

85dB + 13dB = 98dB at 40W
98dB + 3dB(second speaker) + 3dB(room reflections) = 104dB
104dB - 12dB(4m distance) = 92dB

92dB should be plenty loud, IMO.

15' x 20' would be the absolute largest room I could hope for. I am in between houses and my last house would most likely be larger than where I'll end up (bigger city smaller house tradition). I would expect a 10' x 15' room or slightly smaller. I have two pairs of speakers that I have kept over the years: Yamaha NS-1000 and JBL 4349. The JBL's are very efficient as they have been tested to never go below 8ohms. They do require a large room because they project due to the horn. The Yamaha can manage a small room because of wall placement, but I thought it would good to have a second pair of speakers that are bookshelf if I get rid of the 4349. I'm trying to downsize, BUT IT'S TOUGH, as each piece of gear has its own special attributes, i.e. my Yamaha CX-70 has my favorite phono stage. The AsciLabs have been getting good reviews, but the seller I got the Luxman from recommend Alta speakers, so there may be other options. I would think in a reasonable room 40w class A would be enough but it's all in the circuitry......maybe Philharmonic or Kef? Thanks for some great insight more the better. 

enobenetto, I’ve been intrigued by the Genelec G3’s ever since reading about them a couple of years ago. They’re active speakers, so power shouldn’t be an issue.

https://www.genelec.com/g-three#section-technical-specifications

https://www.stereophile.com/content/genelec-g-three-active-loudspeaker

Do Genelec's use DSP for the crossover? I have been intrigued by active speakers but I listen to lots of vinyl so DSP is not viable option for me. Neumann looks cool too.

I'm not sure, you'd have to read up on them. I read about them first in Stereophile Magazine.

Here you go, from the Stereophile article -

the active Genelec G Three is a 100% all-analog, powered two-way monitor.