Amplifier for the KEF LS50s

[detlev24]

[...] This rules out any benefit from sample rates above 48khz and makes higher rated DACs pointless. [...]

Any sample rate above 48 kHz [arguably, 44.1 kHz] rules out any benefit - for music reproduction - and makes higher rated DACs pointless. Unless, for music production, of course.

But there exist some very rare 'human' specimens, that claim to have positive hearing abilities up to and above 24.000 Hz.

 

[SlydZ]

@AudiPersona
These are interesting informations. The LS50s are insanley good priced at the moment. Whats your opinion about the Behringer A800, because the amp has no dsp and got good results in the review here (for a pa amp). I think the compact size of amps like the XTZ or the Audiophonics MPA-S250NC are a really benefit

I'm looking forward for my XTZ EDGE A2-300 and I'm curious how the LS50s will sound with the XTZ.

The downside of the RME ADI-2 FS is that there is no support for balanced headphoneoutput and no MQA support. The quality of the DAC/amp should still be so good that these aren't big disadvantages. For me MQA wasn't that interestering, because I didn't hope for big advantages in quality and I really like the possibilites of the ADI-2 and think it's a great DAC. Do you think MQA makes such a big difference with the LS50s?

 

[AudioPersona]

Any sample rate above 48 kHz [arguably, 44.1 kHz] rules out any benefit - for music reproduction - and makes higher rated DACs pointless. Unless, for music production, of course.

But there exist some very rare 'human' specimens, that claim to have positive hearing abilities up to and above 24.000 Hz.

Is this guy wrong?

 

[AudioPersona]

@AudiPersona
These are interesting informations. The LS50s are insanley good priced at the moment. Whats your opinion about the Behringer A800, because the amp has no dsp and got good results in the review here (for a pa amp). I think the compact size of amps like the XTZ or the Audiophonics MPA-S250NC are a really benefit

I'm looking forward for my XTZ EDGE A2-300 and I'm curious how the LS50s will sound with the XTZ.

The downside of the RME ADI-2 FS is that there is no support for balanced headphoneoutput and no MQA support. The quality of the DAC/amp should still be so good that these aren't big disadvantages. For me MQA wasn't that interestering, because I didn't hope for big advantages in quality and I really like the possibilites of the ADI-2 and think it's a great DAC. Do you think MQA makes such a big difference with the LS50s?

Seems like we're in a similar situation.

I have no opinion on the Behringer A800 other than what I've read here. It's not on my list of potential replacement amps for the Crown.

I do have experience with RME although I used their hdspe pcie soundcard for music production and have never used the ADI-2-FS. The ADI 2 was a serious consideration for me though as the RME HDSPe soundcard that I had was amazingly stable with extremely low latency.

As for MQA, I have some experience with Tidal Masters through the Crown amp which downsamples it to 48khz and also using Sennheiser HD800 headphones out of the pretty bad headphone out on my focusrite 2i4. Going back and forth in Tidal between 44.1 and Master versions of the same tracks, I can definitely hear a difference even via the Crown despite the fact that it's being down sampled. That experience is what made me look into MQA a bit more in depth as I could not understand why I was hearing a difference via the amp. I still don't fully understand it to be honest.

I don't think MQA is a game changer at all though in my humble opinion. It was just enough to move me away from the RME ADI 2 to the SMSL M500 despite its flaws. The SMSL is also cheaper but that is irrelevant as I'll also be buying a good THX style headphone amp in due course.

 

[detlev24]

@SlydZ, do your headphones really require that much power, that you would need to run them balanced? There is no other practical advantage for 'normal' use; search the RME User Forum for more specific information - or have a look at the respective chapter in the ADI-2 Pro series manual.

Again, some 'human' specimens claim to be able to hear a difference between the signal-to-noise ratio of 117 dB/120 dBA [unbalanced] vs. 120 dB/123 dBA [balanced].

@AudioPersona, you tell me! Plenty of objective information about MQA can be found on Archimago's Musings [results not ordered by date].

However, everybody can do his or her own double-blind listening test(s), e.g., with ABX Comparator for foobar2000 - using the exact same track(s), re-sampled losslessly with a converter like 'SoX'.

 

[AudioPersona]

@detlev24 Hmmmmmmmmmm.... I'm getting lost in an MQA rabbit hole here and need to stop, immediately, for my own sanity. I read a few of the posts you linked and it's interesting stuff but there are arguments being made on both sides of this debate so I'm going with my own direct experience (which is also admittedly not infallible).

I can only hear up to around 16.5khz by the way so I guess I need to find some 33khz sample rate files to save on unnecessary file storage sizes. Just kidding, I'm going with MQA.....

 

[Ron Texas]

The Crown 1502 has internal AD-DA which is used in order for the DSP to work. That AD-DA is locked at 48khz and cannot be bypassed. That means that you're always limited by the quality of the Crown's internal AD-DA and can never playback anything at a sample rate above 48khz. This rules out any benefit from sample rates above 48khz and makes higher rated DACs pointless.

Some people who have been trained to hear the difference between Redbook and 96/24 can hear a difference. Most people can not. You might try down sampling some high res tracks to 48/24 and do a blind test. Otherwise you are just looking at numbers and acting on subjective beliefs. As for MQA, you will find many pungent opinions here and most are very unfavorable.

The 48khz limit was mentioned in the review of the XLS 1502 here along with the "limitation". However, our host later gave an XLS 2502 a recommendation. Perhaps you should read both threads before jumping all over it.

If you can hear up to 16.5 Khz you are fortunate. For males over 55 typically the limit is 12 khz and downhill as one gets older.

 

[AudioPersona]

@Ron Texas Thanks. I'll check out the 2502 review.

I used to hold to the belief that beyond a certain very low end point, a DAC is the same as any other DAC and it's all just a bunch of fairy dust but then came the fateful day that I bought an antelope audio orion studio HD, did A/B blind testing vs an RME HDSPe through Genelec 8040s in my treated studio and realized that I was dead wrong. The difference was obvious.

I think blind testing is the ultimate litmus test. I do it all the time in music production. I'm going to do the same with MQA in the near future, once I have my crown amp replaced and the SMSL M500 in place. If I can't reliably tell a difference then... er... well... I guess I'll cross that bridge when/if I get there.

 

[detlev24]

I did not mean to "attack" somebody's believes but here on ASR, facts should be considered in the first place. I have read amirm's reviews of the Crown XLS 1502 and 2502 amplifiers and nowhere did I find an indication, that internal 48 kHz processing would be "the crutch". [Despite those two being entry-level devices, which do perform very well for their price.] But then, English is not my first language and I might have missed this part.

Anyway, Crown amplifiers are made for professional use; where a higher sampling rate might indeed have been beneficial for music production - which is not what ASR does concentrate on. Furthermore, many measured details have no impact on audibility and others which do, are not covered by those measurements [e.g., regarding room acoustics].

Music is about emotions! So, whatever triggers those emotions for somebody, can generally be considered to be good. If MQA triggers emotions, then by all means, go for it. If a 12.000 $ power cable triggers those emotions, and money is no object, then go for it. Just a few silly examples.

Ultimately, for one personally, it does not matter what other human beings can or cannot hear. What matters is what you/one as an individuum hear/s. I do not want to know anybody's results [as only you will know whether you cheated, e.g., with an audio editing software or not] but if you are willing to challenge your own abilities, there a some options available [like Ethan Winer's "High Definition Audio Comparison" and "Is 24-bit Recording Really Better?"].

Furthermore, as long as we do not know the exact specifics of how that mentioned Redbook listening test was conducted and, should it no be repeatable; it simply would have no scientific value.

Ladies and Gentlemen: First enjoy the music, then enjoy your gear!

 

[GXAlan]

Any sample rate above 48 kHz [arguably, 44.1 kHz] rules out any benefit - for music reproduction - and makes higher rated DACs pointless. Unless, for music production, of course.

But there exist some very rare 'human' specimens, that claim to have positive hearing abilities up to and above 24.000 Hz.

Isn't the main advantage getting rid of the potential issues of the digital filter at the Nyquist frequency?
https://goldmund.com/does-high-resolution-audio-sound-better​/

 

[detlev24]

Which 'potential issues of the digital filter at the Nyquist frequency' are you referring to? I am not an engineer, so I cannot answer this question specifically. However, I found a document about "What the Nyquist Criterion Means to Your Sampled Data System Design"; if that is what we are talking about. The only part that I had heard of before was, that it has to do with antialiasing filters (for ADC) and, that the sampling rate needs to be at least 2x the highest frequency contained in a signal - which is why, e.g., a 44.1/48 kHz sampling rate would allow for reproduction of up to 22.05/24 kHz.

As far as I know, there is no audible drawback with those lower [but absolutely sufficient] sampling rates on properly designed DAC stages - not even on inexpensive ones. Actually, with a higher probability, the opposite might be the case.

Admittedly, I was surprised to read that a manufacturer like Goldmund, who - besides other 'gems' - sells a 236.000 € turntable, would not promote "HiRes" audio. Their information is mostly accurate but unfortunately, lacks links to all the important references.

 

[Objectivist01]

Bottom line is, I would not be too concerned of such subjective recommendations. Those people would wonder, if they actually measured the provided W + the loudspeaker's distortion at their listening levels.

No, I would not even try to push the LS50 to its limits! Everything above 90 dB SPL would hurt my ears, for sure, due to its rising distortion levels. The LS50 is, by its physical limitations, not made for a deep bass reproduction at high SPL. If you want that, extend your setup with a properly crossed-over subwoofer. This way, you would take the load off the LS50, as the 5.25" LF/MF-woofer would not require to reproduce the lowest frequencies anymore; which you would be "routing" to the subwoofer(s). If you would force the LS50 to its maximum woofer excursion and beyond; you might as well break the woofer permanently.

To make it more obvious, one example, regarding the distortion graph I posted above. If we take the two green lines, which are supposed to be at 90 dB SPL. The horizontal grid lines must be spaced by 5 dB then. This gives, in case of a 60 Hz tone: Difference between fundamental [upper green curve] and distortion levels [lower green curve] = ~24 dB. By application of the formula to calculate THD in %, this would equal ~6.3 % distortion at 60 Hz and 90 dB SPL. At just around 40 Hz, distortion would therefore reach 100% (!) and also passing 60 Hz it would rise again; until it finally decreases when passing 90 Hz. // For this example, theoretically, only 32 W at 8 Ω would be required to reach 90 dB SPL in the LS50's bass region [1-meter distance; 1 loudspeaker. Two combined, as usual, would provide roughly +3 dB output].

@Ron Texas Thanks. I'll check out the 2502 review.

I used to hold to the belief that beyond a certain very low end point, a DAC is the same as any other DAC and it's all just a bunch of fairy dust but then came the fateful day that I bought an antelope audio orion studio HD, did A/B blind testing vs an RME HDSPe through Genelec 8040s in my treated studio and realized that I was dead wrong. The difference was obvious.

I think blind testing is the ultimate litmus test. I do it all the time in music production. I'm going to do the same with MQA in the near future, once I have my crown amp replaced and the SMSL M500 in place. If I can't reliably tell a difference then... er... well... I guess I'll cross that bridge when/if I get there.

thr dacs which you mention won’t be measuring the same. Hence you heard a difference.

 

[Aerith Gainsborough]

Isn't the main advantage getting rid of the potential issues of the digital filter at the Nyquist frequency?
https://goldmund.com/does-high-resolution-audio-sound-better/

A very honest view of Hi-Res audio in that link.
I like it.
The potential filter problems are solved via oversampling at the DAC stage.

I agree with the linked article: forcing consumer gear to operate out of spec and reproduce ultrasonic frequencies can only degrade the sound quality. If people actually manage to hear differences, they're most likely sensing artifacts that should not be there in the first place. best case scenario: you waste a ton of resources on gear specifically designed to handle ultrasonics and don't get any artifacts, which basically means you are back where you started with plain old 44.1/16.

 

[al2813]

For those in Europe, a German store is currently offering the black LS50s for 666 Euros (and in my case 30 euros shipping to Belgium). Could not resist and pulled the trigger today. This means I will have to get an amp as I don’t think my current one can drive them.....

 

[Objectivist01]

For those in Europe, a German store is currently offering the black LS50s for 666 Euros (and in my case 30 euros shipping to Belgium). Could not resist and pulled the trigger today. This means I will have to get an amp as I don’t think my current one can drive them.....

This was the price for some time in Germany . Not in one store but in more places, had seen it for 599 some time back even.

 

[SlydZ]

My first impression of the combination is really nice:
PC -> RME ADI-2 DAC FS -> xtz edge a2-300 -> KEF LS50

Firstofall all devices look really nice and are well constructed.
The sound is very clean, can't hear any hiss - only clean sound - thats really new for me and so impressive. I'm overwhelmed by the dynamic.

I have to say, that I have no comparision to similar systems, but I can highly recommend this combination. I'm now glad that I bought the XTZ. There is a lot of headroom and the form factor is really nice. It fits perfecty on top of a desktop PC.

I have only one problem: If I have the Tidal exclusive mode on I have "noises" if i skip the song or pause. I tried different USB Ports even USB 3.1

edit: fits not to the topic
I tried my AKG k551 headphones with: PC (USB) --> RME ADI-2 DAC FS (IEM port)
I used them hardly in recent years, because for my taste they were too flat and "boring". I used them before with a simple Beyerdynamic UCA202 DAC. They sound soo different now with the ADI-2 and soo much better, although they are not difficult to drive. Can't believe that the ADI-2 makes so much difference.

 

[Objectivist01]

My first impression of the combination is really nice:
PC -> RME ADI-2 DAC FS -> xtz edge a2-300 -> KEF LS50

Firstofall all devices look really nice and are well constructed.
The sound is very clean, can't hear any hiss - only clean sound - thats really new for me and so impressive. I'm overwhelmed by the dynamic.

I have to say, that I have no comparision to similar systems, but I can highly recommend this combination. I'm now glad that I bought the XTZ. There is a lot of headroom and the form factor is really nice. It fits perfecty on top of a desktop PC.

I have only one problem: If I have the Tidal exclusive mode on I have "noises" if i skip the song or pause. I tried different USB Ports even USB 3.1

edit: fits not to the topic
I tried my AKG k551 headphones with: PC (USB) --> RME ADI-2 DAC FS (IEM port)
I used them hardly in recent years, because for my taste they were too flat and "boring". I used them before with a simple Beyerdynamic UCA202 DAC. They sound soo different now with the ADI-2 and soo much better, although they are not difficult to drive. Can't believe that the ADI-2 makes so much difference.

K551 and flat?

 

[SlydZ]

K551 and flat?

It's not sure that the headphone was in a good condition. I bought the K551 in 2014 for 50€ in new condition. At this time the normal price was at ~200€. There were some rumor that this was a bad charge, because many people were disappointed (not so much bass and much highs). Some buyers recognized bad smell from package and headphones (smell burned). The ebay electronic shop selled over 200 pieces in a few days. So could be that the shop bought the hole charge.

I can imagine that the most people had not the best audio equipment and bought them because of the low price andpaired them only with their smartphone. My AK551 profit really from the ADI-2 Dac.

 

[SlydZ]

Last test is: PC -> ADI-2 -> Focal Stellia

Interesting is that I hadn't a "wow-effect" in the first minutes. The longer I listen, the better they sound. I think you have to get used of it first. Again, I have no comparison to headphones in a similar price range. Bass, highs and mids are just right for the first impression (1-2h). Details and clarity are impressive. The power of the IEM output is more than enough.

 

[Angsty]

Steve Guttenburg did a favorable review of the Denon PMA-600NE paired with the KEF LS50. If you are considering an integrated with a phono input, it may be worth consideration. I only mention it because it does have a 4 ohm rating of 70W with a price of $400.