Luxman SQ-N150 Review (Tube Amplifier)

[Ken Tajalli]

The tubes are fine. Its the designer tube sockets which are not matched.

Can you elaborate please.
Thanx

 

[egellings]

Homologation?

 

[EL_PW]

This is my unit and I just wanted to make a couple of comments.

I accept the testing as accurate and commend Amir for his tireless efforts on our behalf. And I'd much rather know the truth so am not disheartened by the results. I use high efficiency speakers (Omega Super 3i) with the unit and its sounds pretty good - not amazing but pretty good. And Amir is very correct that a smidge too much volume and its distortion city baby. But why is that? For people considering this unit something to keep in mind is that it was designed for the Japanese market where people live in apartments made out of paper, literally. You can hear your neighbors moving around next door and all their conversations that are above a whisper. So a pretty tube amp that sounds best at micro volume with high efficiency speakers makes sense in that context. Sadly, this has a corollary in the US as now our Landed Gentry are forcing us into expensive, small and smaller apartments and condos where those same considerations from Japan apply. Folks in Europe may or may not be able to relate. Old buildings with thick walls are best for audio nirvana IMHO.

I also have class A/B (Rotel RB-1070, Hafler DH-220) and Class D (Topping PA3s, Hypex UcD 400 amp kit)) amps that sound GREAT but had always wanted something that was "Pure Class A" which is the Luxman. Now I realize just how much hype I've been exposed to in the hi-fi/audiophile industry and have the knowledge to make much smarter choices going forward.

Cheers!

 

[DMill]

This is my unit and I just wanted to make a couple of comments.

I accept the testing as accurate and commend Amir for his tireless efforts on our behalf. And I'd much rather know the truth so am not disheartened by the results. I use high efficiency speakers (Omega Super 3i) with the unit and its sounds pretty good - not amazing but pretty good. And Amir is very correct that a smidge too much volume and its distortion city baby. But why is that? For people considering this unit something to keep in mind is that it was designed for the Japanese market where people live in apartments made out of paper, literally. You can hear your neighbors moving around next door and all their conversations that are above a whisper. So a pretty tube amp that sounds best at micro volume with high efficiency speakers makes sense in that context. Sadly, this has a corollary in the US as now our Landed Gentry are forcing us into expensive, small and smaller apartments and condos where those same considerations from Japan apply. Folks in Europe may or may not be able to relate. Old buildings with thick walls are best for audio nirvana IMHO.

I also have class A/B (Rotel RB-1070, Hafler DH-220) and Class D (Topping PA3s, Hypex UcD 400 amp kit)) amps that sound GREAT but had always wanted something that was "Pure Class A" which is the Luxman. Now I realize just how much hype I've been exposed to in the hi-fi/audiophile industry and have the knowledge to make much smarter choices going forward.

Cheers!

I wouldn’t be too bothered by measured results. It’s a lovely tube amp, and by design, has its flaws. I also am fortunate to have a nice 2nd system similar to this and enjoy it for what it is. Kinda like the Rush song Red Barchetta about a guy who takes his combustion vehicle out for a ride when technology has surpassed it. I bet playing most music at normal levels it can do just fine. If you want SOTA no. But it’s probably a fun ride.

 

[MaxBuck]

Mac, H-K Citation, these were some terrific amps.

They were terrific amps for their time that now are completely taken to the woodshed by a $200 Topping.

As for the Luxman and similar tube amps: is it possible that they're just the tickety-boo for people who listen to crap source material and just want it smoothed out and muffled in a pleasing manner? I'm talking to you, vinyl aficionados, among others.

 

[EL_PW]

They were terrific amps for their time that now are completely taken to the woodshed by a $200 Topping.

As for the Luxman and similar tube amps: is it possible that they're just the tickety-boo for people who listen to crap source material and just want it smoothed out and muffled in a pleasing manner? I'm talking to you, vinyl aficionados, among others.

It's funny you say that. I have a pro-ject turntable that I hooked up to the tube amp and then purchased about 10 records to listen to of jazz, classical and rock. After listening to all of them a number of times I realized that I'd much rather have the CD versions of all those recordings and stopped buying vinyl altogether. And I grew up with vinyl so if anyone should love it it's me. But the Luxman and digital sources can sound very nice together. But as you mentioned, they don't beat my Topping PA3s.

 

[Ken Tajalli]

Isn't it amazing how some people's goal-posts seem to shift according to their agenda!
I mean, sometimes a SINAD figure of 120dB is vastly superior to a measly 90dB SINAD, at other times a distortion figure of -90dB is "Pretty inaudible"! And when it comes to speakers and transducers, once we pass a distortion level of -40dB, all is rosy!
Make up your minds, will you! I am talking to you Test-gear Aficionados!
A good LP playing system, with or without Tube amplification CAN (not all) sound so good, you get goose pimples! But it would be expensive, maintenance intensive, jittery etc. Not to mention archaic technology.
But to a HIFI hobbyist, all is part of the fun.
In contrast, one can get a decent digital playback system, for a lot less money, which would be modern, maintenance free etc.
But that does not make the LP system Crap! Just expensive and fiddly.
I am of the firm belief that this sample of Luxman amp is actually faulty! The test results are not indicative of this design, something is broken on this particular unit, it needs a repair/service. Something is wrong with the differential stage balance.
The other day, I stumbled on "Walk on By " cover by The Stranglers, on my phone. It started playing on the phone tiny speaker! Now this is a punchy, angry song. But I listened to it to the very end at 6.5 minutes long. The music was so good, the equipment just faded away . . . .

 

[Dmaumau]

For amps and other electronics, yes, they do.

No, they very much DO NOT.

 

[Jim Taylor]

No, they very much DO NOT.

Well, well .... you seem to have a very firm opinion there. Care to tell us about it? Jim Taylor

 

[watchnerd]

That was back when they were trying to minimize distortion, not turn it into a selling point.

Here are a couple of ads from the day. Focus seems to be on fidelity, not a pleasing distortion profile.

View attachment 214155

I want this as a poster!

 

[SIY]

No, they very much DO NOT.

Evidence?

 

[captainbeefheart]

The 2nd harmonic should not dominate in properly designed Push-Pull construction.

This is true because in decent designs the power stage produces the most distortion. BUT, I do know at least one builder that has a decent client base that in his push pull designs he purposely designs them with higher second harmonic vs third.

This can be done by bad balance in the power stage as mentioned here but he has good balance in the output tubes and output transformer, during a conversation he did allude to making the voltage gain stages non-linear while also using a poorly balanced long tailed pair phase inverter. Some argue the phase inverter is part of the power section so in that regard yes it's the power stage that isn't balanced.

This amp uses a split load phase inverter which typically has very good balance with equal plate/cathode loads, but in theory you could offset the loads and have poor balance.

I'll agree with the logic that this specific unit needed to have it's fixed bias balance checked before testing and maybe we would have seen better test results. The amp has current sense resistors in the power tube cathodes and looks like balance controls for bias so it should be an easy task to check balance and retest once adjusted for better current balance between power tubes.

 

[Robaroni]

I'm not going to pan this amp. Sure it cost a lot but it's Luxman and they build quality into their amps, I'm sure this one will last. While I'm not a fan of tube outputs I do like tube/hybrid preamps but not SS in front of the tube, the other way around.
People like second harmonic distortion, I can't blame them. Running this amp into low to medium efficiency speakers is a mistake, it's just not designed for that. It's a ten watt small room or desktop amp for Pete's sake. Of course with medium efficiency speakers ten feet away you're going to turn the volume up - what did you think was going to happen??
My criteria is the DBT. Find what you like then listen to it for hours, if it doesn't fatigue your ears then you have a winner. Specs are great but specs aren't musicality, who's to say what an individual likes and we all like different sound. I can see why people love this amp, even if I don't, I can respect that.

 

[Dagwood]

This does nothing the most mediocre chip amp can‘t do - except cost 30x as much.
But then again, millions or people believe in homeopathy, at least this doesn‘t do any harm.

Doesn't allopathic have something in common with viruses and bioweapons? Yep they all originate from a lab!

 

[egellings]

???...

 

[fpitas]

That 20Hz performance is downright special. When you build an economy amp like this, you can't afford the best output xfmr, I guess.

 

[fpitas]

That was back when they were trying to minimize distortion, not turn it into a selling point.

Here are a couple of ads from the day. Focus seems to be on fidelity, not a pleasing distortion profile.

View attachment 214155

View attachment 214154

Yeah, that was back when engineers designed the good stuff. Not audiophiles.

 

[DonDish]

This is a review and detailed measurements of the Luxman SQ-N150 hybrid integrated amplifier with phono stage. It is on kind loan from a member and costs US $3,295.
View attachment 212863
Can you say pretty? I knew you could! Love the elegant front panel with VU meter. Nice set of balance and tone controls are provided as well:

View attachment 212864
As you can see, power amplification is provided through ECC83 triode drivers going to EL84 power tubes. Amplifier is conservatively designed and is rate at just 10+10 watts into 6 ohms. I like the look without the cage but here it is with:

View attachment 212865

Not much exciting in the back other than modern, beefy speaker terminals than that of vintage tube amplifiers:
View attachment 212866

The package is smaller than one imagines but weighs a hefty 27 pounds. Notice the AC terminal doesn't have earth ground and unit is double insulated. In testing I found no effect from earthing the unit or not.

Front-end and pre-amps are solid state:

View attachment 212868

Luxman SQ-N150 Amplifier Measurements
When I picked 5 watts as my standard for measuring amplifiers, it was usually a fraction of the amplifier power but here it is nearly half the available power! So relatively speaker, distortion plays a much strong role than it would otherwise:
View attachment 212867

The high second and third harmonics set the stage as far as SINAD (due to push-pull design) but I wish there was not so much power supply noise. Sadly the amplifier takes up the ranking of second worst amplifier I have ever measured as far as distortion+noise:
View attachment 212869

Those power supply spikes set the lower bound for dynamic range:
View attachment 212870

It is not too bad but you likely will use very sensitive speakers with this low power amplifier so the numbers may manifest themselves more than they usually do.

Frequency response is extended but shows a kink indicating some kind of filter:
View attachment 212871

Crosstalk does not follow the usual curve indicating some sort of resistive (?) element between the two channels:
View attachment 212872

Normally the issue is capacitive which causes the two reference lines you see.

Multitone which is supposed to resemble "music" with its 32 tone, shows strong level of "grass" (intermodulation distortion):
View attachment 212873

Hard to make a case that you are hearing more detail when so much is masked at this power level.

I don't have a 6 ohm load so used my usual 4 and 8 ohm loads for power testing:
View attachment 212874

View attachment 212875


View attachment 212876

Edit: forgot to post the different frequency sweeps:

View attachment 213080

Luxman SQ-N150 Phono Stage Measurements
The amplifier noise and distortion dwarfs the phono stage so I only checked its frequency response:
View attachment 212877

So very good on this critical measurement.

Luxman SQ-N150 Headphone Measurements
For same reason as above, I just made a power measurement:
View attachment 212878

Seems usable from power availability point of view but noise and distortion are quite high. Company specifies 16 ohm output impedance and wisely recommends against using low impedance headphones for good reason:

View attachment 213081

The headphone amplifier is simply connected to the amplifier output using the aforementioned resistor which eats up all the power. It will also change the frequency response of your headphone if it is not flat. So best to be avoided.

Luxman SQ-N150 Listening Tests
My lab speaker is an infinity R253 which has a sensitivity of 87 dB. I connected it to the SQ-N150 and started to listen. I had to immediately acknowledge the lack of power as the volume control not only maxed out but there was so much distortion as to cause crackling noise. I backed off to moderate listening level and the sound was OK but I noticed boominess in the lows as if you have more room modes than you do. To confirm, I switched to Topping PA5 amplifier on my bench and boominess was gone. Likely the harmonic distortion of the amplifier is hitting on more room modes causing extra bass/boominess. I can see if your speakers/setup lacks bass that you experience a bit more of it.

The volume control had to be kept below 12:00 o'clock. By 1:00 o'clock distortion would start to set in and sound would start to get grungy and rough. Past 2:00 o'clock it would be rather obvious and beyond that, unusable. There was usable volume with me sitting 5 feet from the single speaker. With two speakers you could double that but it is still not enough power for me with this speaker. If an audio reviewer can't hear this level of distortion, they should give up testing audio gear. Sadly none of the reviews I read made a remark about the distortion.

It is the classic case of paying a lot more and getting a lot less fidelity and enjoyment.

Conclusions
The high level picture here is very clear: wonderful looking, and presumably well built amplifier. The problem is using tube technology and producing so little power. I see no advantage to it, euphonically or otherwise. But it is possible for some people the bass impact is a positive. But at what cost? So much spent with so little dynamic capability due to lack of power.

Needless to say I can't recommend the Luxman SQ-N150.

------------
As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

This has got to be the most stupid/evil test I ever saw.

This is a review and detailed measurements of the Luxman SQ-N150 hybrid integrated amplifier with phono stage. It is on kind loan from a member and costs US $3,295.
View attachment 212863
Can you say pretty? I knew you could! Love the elegant front panel with VU meter. Nice set of balance and tone controls are provided as well:

View attachment 212864
As you can see, power amplification is provided through ECC83 triode drivers going to EL84 power tubes. Amplifier is conservatively designed and is rate at just 10+10 watts into 6 ohms. I like the look without the cage but here it is with:

View attachment 212865

Not much exciting in the back other than modern, beefy speaker terminals than that of vintage tube amplifiers:
View attachment 212866

The package is smaller than one imagines but weighs a hefty 27 pounds. Notice the AC terminal doesn't have earth ground and unit is double insulated. In testing I found no effect from earthing the unit or not.

Front-end and pre-amps are solid state:

View attachment 212868

Luxman SQ-N150 Amplifier Measurements
When I picked 5 watts as my standard for measuring amplifiers, it was usually a fraction of the amplifier power but here it is nearly half the available power! So relatively speaker, distortion plays a much strong role than it would otherwise:
View attachment 212867

The high second and third harmonics set the stage as far as SINAD (due to push-pull design) but I wish there was not so much power supply noise. Sadly the amplifier takes up the ranking of second worst amplifier I have ever measured as far as distortion+noise:
View attachment 212869

Those power supply spikes set the lower bound for dynamic range:
View attachment 212870

It is not too bad but you likely will use very sensitive speakers with this low power amplifier so the numbers may manifest themselves more than they usually do.

Frequency response is extended but shows a kink indicating some kind of filter:
View attachment 212871

Crosstalk does not follow the usual curve indicating some sort of resistive (?) element between the two channels:
View attachment 212872

Normally the issue is capacitive which causes the two reference lines you see.

Multitone which is supposed to resemble "music" with its 32 tone, shows strong level of "grass" (intermodulation distortion):
View attachment 212873

Hard to make a case that you are hearing more detail when so much is masked at this power level.

I don't have a 6 ohm load so used my usual 4 and 8 ohm loads for power testing:
View attachment 212874

View attachment 212875


View attachment 212876

Edit: forgot to post the different frequency sweeps:

View attachment 213080

Luxman SQ-N150 Phono Stage Measurements
The amplifier noise and distortion dwarfs the phono stage so I only checked its frequency response:
View attachment 212877

So very good on this critical measurement.

Luxman SQ-N150 Headphone Measurements
For same reason as above, I just made a power measurement:
View attachment 212878

Seems usable from power availability point of view but noise and distortion are quite high. Company specifies 16 ohm output impedance and wisely recommends against using low impedance headphones for good reason:

View attachment 213081

The headphone amplifier is simply connected to the amplifier output using the aforementioned resistor which eats up all the power. It will also change the frequency response of your headphone if it is not flat. So best to be avoided.

Luxman SQ-N150 Listening Tests
My lab speaker is an infinity R253 which has a sensitivity of 87 dB. I connected it to the SQ-N150 and started to listen. I had to immediately acknowledge the lack of power as the volume control not only maxed out but there was so much distortion as to cause crackling noise. I backed off to moderate listening level and the sound was OK but I noticed boominess in the lows as if you have more room modes than you do. To confirm, I switched to Topping PA5 amplifier on my bench and boominess was gone. Likely the harmonic distortion of the amplifier is hitting on more room modes causing extra bass/boominess. I can see if your speakers/setup lacks bass that you experience a bit more of it.

The volume control had to be kept below 12:00 o'clock. By 1:00 o'clock distortion would start to set in and sound would start to get grungy and rough. Past 2:00 o'clock it would be rather obvious and beyond that, unusable. There was usable volume with me sitting 5 feet from the single speaker. With two speakers you could double that but it is still not enough power for me with this speaker. If an audio reviewer can't hear this level of distortion, they should give up testing audio gear. Sadly none of the reviews I read made a remark about the distortion.

It is the classic case of paying a lot more and getting a lot less fidelity and enjoyment.

Conclusions
The high level picture here is very clear: wonderful looking, and presumably well built amplifier. The problem is using tube technology and producing so little power. I see no advantage to it, euphonically or otherwise. But it is possible for some people the bass impact is a positive. But at what cost? So much spent with so little dynamic capability due to lack of power.

Needless to say I can't recommend the Luxman SQ-N150.

------------
As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/

The most stupid/evil test ever. @amirm you take a 10+10 valve amp and put it up against top transistor contenders like topping and BM ahb-2. At the listening test you dust off your old infinitys with a 87db/w sensivity rating. This is just set up to fail the Luxman amp. For an amp like this to work, you would need a 95 - 105db/w speaker. Back in the days when transistors where just a ski-fi dream in some engineers head, they built speakers to match these low output amps ie horns and lightweight pulp membranes. This isnt fair by a mile.

I still remember those old, pre transistor, teak furniture TV´s and radios. They had beautiful midrange rich valve sound that could easily fill a room with lots of volume to go.

When you dont have the gear or possibly the know-how to test valve amps, you should just make it a pass. This was embarrassing.

If you remember these you know what im talking about:

 

[amirm]

For an amp like this to work, you would need a 95 - 105db/w speaker.

"You" need such a speaker. I don't. I test every amplifier the same because the purpose of every amplifier is the same: to amplify the input as faithfully it can and provide proper amount of power. I am not the PR person for the company to go out of my way to pick a speaker for it so that its meager amount of power does some good. That is for you to do if that is the role you want to play.

When you dont have the gear or possibly the know-how to test valve amps, you should just make it a pass. This was embarrassing.

What is embarrassing is folks coming out of woodwork, trying to defend manufactures so more poor consumers go and buy stuff like this. This is the second worst amplifier I have tested of all kinds including tubes. You want to make excuses for it, do it elsewhere.

 

[fpitas]

This has got to be the most stupid/evil test I ever saw.


The most stupid/evil test ever. @amirm you take a 10+10 valve amp and put it up against top transistor contenders like topping and BM ahb-2. At the listening test you dust off your old infinitys with a 87db/w sensivity rating. This is just set up to fail the Luxman amp. For an amp like this to work, you would need a 95 - 105db/w speaker. Back in the days when transistors where just a ski-fi dream in some engineers head, they built speakers to match these low output amps ie horns and lightweight pulp membranes. This isnt fair by a mile.

I still remember those old, pre transistor, teak furniture TV´s and radios. They had beautiful midrange rich valve sound that could easily fill a room with lots of volume to go.

When you dont have the gear or possibly the know-how to test valve amps, you should just make it a pass. This was embarrassing.

If you remember these you know what im talking about:

View attachment 231923

Your nostalgia has taken you away from the actual history. They tested amplifiers "back in the day" in a very similar manner. Some of the best engineers of the time devoted their lives to getting low distortion from tube amps. Good amps weren't used in teak furniture TVs and radios; no engineer of the time thought that was high fidelity. But companies like Altec that made the horns you speak of made state of the art amps to drive them., with low distortion.

In any event, you're on ASR. Amir tests things for objective performance. You are free to interpret (or ignore) it as you please.

And yes, I had a magic eye tube when I was a kid