Help me decide on an amp for KEF LS50 meta

surr3a1

Standard Member
Hi all,
I now own a Bluesound Powernode which powers the KEFs. I like the sound of this combo but I know that it can be better if I get a just a Node and add a separate Amp.

I had auditioned the KEFs with Arcam SA20(or 30 not sure) before I got them and the sound was a little better with more details in the vocals. This is how I know it can be better.

Additionally I know that the Audiolab 6000a sounds better than the Powernode but because of the 50W I'm inclined towards the 8300a.

I am a BluOS fan and don't want to change that for sure.

What amp/dac combo should I choose:

  • Arcam SA20 - probably the best price. Only one I've actually heard and I liked it
  • Audiolab 8300a (I need a DAC(Ares II) here and that makes it by far the most expensive setup... worth?)
  • Cambridge CXA81 - 3 years WhatHiFi favorite but is that objective?

All-in-one solution:
Roksan Attessa Streaming Amp - very beautiful and everything in one device. Price is just a little over the other amps+Node combos. It is too new though and reviews are lacking.

Any advice is welcomed.

Thanks!

P.S.

The Powernode has both low/high pass filter applied to the speakers/sub. Without this the bass from the speakers is not good. Too boomy and unclear as they are around 20-30cm from the front wall. I really want these to be high filtered and somehow I think that nothing without this will sound good at all. I've yet to find anything on the market that would do this... The hogh pass filter on the speakers adds more clarity and detail and clearly audible by anyone - this is needed!
 
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gava

Well-known Member
I guess that you are listening quite loud or quite far from the speakers(or you have absolutely no idea what you're talking about). I don't think that I am using even 20w of power at any given moment with very very very rare use of ~30w(I am counting 10db headroom).

So when KEF themselves amplify those speakers for the Wireless II version:

Each tweeter is driven by a 100W class A/B amplifier that delivers a smooth, incredibly detailed treble performance. Dedicated 280W class D amplifiers power the mid/bass drivers,

Essentially using what would need at least 2 x 380W amplifier for passive equivalents it's because they don't know what's required to properly drive their own speakers? I also had to use my Behringer A800 to drive them properly in my room.

 
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Kapkirk

Active Member
I am actually starting to get used to the Arcam. Streaming through Chromecast is a bit tricky but once it starts working, it is nice and streaming Soundcloud is absolutely perfect. Tidal is a no go if you want MQA(I know it is crap but still some songs are Ok).

Anyhow, the sound is so much better than the Powernode and having played with the Dirac for a couple of days now, I can say that it is really nice but not beginner friendly in any imaginable way.
Another week or two and by the New Year I believe I won't be missing the BluOS that much.

If I get the Node, I'll be using the Coax out bypassing its DAC and using the one from the Arcam, which is supposed to be quite adequate from what I've read.
The DAC in the node 3 is actually quite decent (I have tested it against a few cheaper DACs and the one built into my Denon PMA1600 ) it sounds very open with nice clean detail at the top and has superb clarity, bass can be a little lean however, the output from the USB is also good (much stronger bass) and is actually better than through coax digital out. I have my node connected through a pair of chord c-line phonos into my amp and this produces the best quality of all and enables me to benefit from mqa streams from paradise.
And if you think you are getting high quality from Spotify, you're not! switching between compressed streams from spotify to hi-res from qobuz and spotify is not even in the same league for sound quality as qobuz at the moment. And from previous comments there's not many titles I can't find on qobuz and at 12 quid a month I'm very happy with qobuz. Agreed it could be easier to use though.
It might be worth the op looking for Cyrus HD to pair with the KEF's and a stand alone Node. The cyrus is a very capable, powerful detailed and fast sounding amp and can be had for around £7-800 at the mo..
 
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surr3a1

Standard Member
No need for that at all!
Anyone stating that he needs 200w of power to power the Metas is misleading everyone after him. Sorry but I can't stand this kind of nonsense if he is not deaf or not listening in a Zeppelin hangar...
 
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Joe C

Distinguished Member
Anyone stating that he needs 200w of power is misleading everyone after him. Sorry but I can't stand this kind of nonsense if he is not deaf or not listenimg in a Zeppelin hangar...

You can disagree, but behave decently when doing so
 
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surr3a1

Standard Member
You can disagree, but behave decently when doing so
Of course, I didn't want to insult anyone and if that was how my comment was perceived - I apologise!

Have a good New Year!
 
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HiFiRuss71

Distinguished Member
....in order to reach their true potential more power is needed, a couple hundred watts is the bare minimum I'd consider.
Err? Plug the data into this. LS50s are capable by KEFs own figures of 106dB off the recommended MAXIMUM of 100W and that tracks with their sensitivity claim of 85dB/2.83V at 1m.

1 metre.

Nobody who values their hearing would listen at 109dB (peaks) at one metre and LS50s can't do it at the required 200W you espouse.

Based on 100W and 3-4m typical of a front room, that's still 99dB. I'm running floor standing 3-ways with 12" bass drivers and 99dB peak is uncomfortably loud and they're cruising at this level. God knows why you'd want to do this with some stand mounted dog-whistlers?

The thing is, the PA5 has been objectively tested to death online. I consider it to be a clean 85W at 4 Ohm. In my case, that's about 60W more than I need to go deaf, but in the case of the LS50s, it's still enough to raise a realistic 97dB at 4m and there is headroom in the PA5 to spare for transients.

Either way, distortion from the speakers will be at least two orders of magnitude worse than the PA5 and higher power won't solve it.

Russ
 
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3rdignis

Active Member
I like the look of the metas, these are the numbers I would aim for.
Not sure they are achievable on the metas.
I have a small room and don't listen loud.

Screenshot_20220102-164243_Samsung Internet.jpg
 
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gava

Well-known Member
I think the Crown figures are in an open space or bigger room. In a small room you will be okay with less, but perhaps not as much less as some people would think.

My experience at 3m listening position in my medium sized room was that my Marantz PM7000N, whilst able to go quite loud was clearly struggling.

My Behringer A800 was very capable, and although perhaps wouldn't measure quite as well as the Marantz - the extra power was far more important than the average performance of the A800.

I have been using the Marantz and LS50 nearfield and obviously it's more than capable for that sort of thing, only a few Watts are necessary.
 
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3rdignis

Active Member
The crown calculator is conservative, also you would be okay with 15db for peaks.
 
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TB Rich

Active Member
I like the look of the metas, these are the numbers I would aim for.
Not sure they are achievable on the metas.
I have a small room and don't listen loud.

View attachment 1628816
Sorry but this is a case of GIGO.

The LS50 Meta are 85dB not 83dB sensitive.
That alone reduces your figures from 298w to 188w - massive % reduction there.

Also 20dB of headroom, way more than you need to input. If you‘re listening so that the nominal average is 80dB at your seat, you wouldn’t need 20dB on top to cover 100dB!
Realistically and in practical terms the 80dB volume you’re listening to already consumes a large amount of the upper portion of the musics overal dynamic range, and so 12dB would easily cover you.
Heck for arguments sake we’ll double even that (so 15dB), and that changes your numbers to 60w.

As Gava says, it also doesn’t take into account reflected sound additions which means you won’t need as much power as even 60w. The reflected additions are difficult to model and is specific to your listening environment. I’ve seen it quoted typically to be about 2dB +/- 1dB for typical listening room environments.

None of this also takes into account the fact speakers vary in impedance, and an amps power varies directly as a result! E.g loud transient bass peaks don’t have to be considered in an amplifiers basic 8ohms RMS 0.1% figure! A decent amp will close to double down at 4ohms, and also have a decent amount of capacitance and decent PSU to sustain peaks before clipping.

Short version, surr3a1 is right. Unless you’re in a huge room, or listening very far away, you don’t need 200w to drive LS50’s, that’s a joke.
Whilst the LS50’s are fairly low sensitivity they’re not that terrible and I’ve seen many happy LS50 owners on the KEF forums running things like Powernodes and even valve amps.
 
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Paul7777x

Distinguished Member
The bare power output figures in watts of any amp are misleading in this context.

What matters is if the amp can cover the necessary current, at sufficient speed, to cover any and all whopping holes in the Ohm curve of any given speaker and the requirement of the music (or film soundtrack) at any point.

The more robust the power supply the better. Bigger, higher temp’ supply capacitors as a single instance are more important than the manufacturers power output claims on the back of the amp.

As in the Naim example above. Even their smaller amps have huge reserves for exactly that job.
 
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Mad Monk

Active Member
Short version, surr3a1 is right. Unless you’re in a huge room, or listening very far away, you don’t need 200w to drive LS50’s, that’s a joke.
Whilst the LS50’s are fairly low sensitivity they’re not that terrible and I’ve seen many happy LS50 owners on the KEF forums running things like Powernodes and even valve amps.
Just curious in case you're right and that Harman are wrong on the above figures, I'm curious as to why KEF have placed nearly double your quoted 200W amplification into each active LS50 speaker?
 
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TB Rich

Active Member
Just curious in case you're right and that Harman are wrong on the above figures, I'm curious as to why KEF have placed nearly double your quoted 200W amplification into each active LS50 speaker?
Harmans (and any amplifier calculator) figures in strict mathemtics are right, but as I said (GIGO) Garbage In Garbage Out - a calculator needs a modicum of understanding to obtain useful figures, as a guide. I’m not quoting any figures, you’ve not digested my post and understood correctly the wider implications of what I was suggesting then.
With respect to KEF’s active speakers, do remember that KEF are no doubt providing enough power to drive them to their maximum possible 108dB SPL with no clipping or excessive distortion; so if you don‘t value your hearing then anyone is welcome to crank them up! :D
 
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3rdignis

Active Member
I've had 2 amps in the past 20 years.
The audiolab 8000s, then 8300mb.
About 20% difference in sound quality.
 
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Mad Monk

Active Member
Harmans (and any amplifier calculator) figures in strict mathemtics are right, but as I said (GIGO) Garbage In Garbage Out - a calculator needs a modicum of understanding to obtain useful figures, as a guide. I’m not quoting any figures, you’ve not digested my post and understood correctly the wider implications of what I was suggesting then.
With respect to KEF’s active speakers, do remember that KEF are no doubt providing enough power to drive them to their maximum possible 108dB SPL with no clipping or excessive distortion; so if you don‘t value your hearing then anyone is welcome to crank them up! :D
Wish I'd never wasted my time reading Toole and going over pages of Harman research back in the day, blind ABX testing blah yadda blah. All I needed was to speak with TB Rich over at AVforums dishing out the alpha and I would've been 'sorted'.
 
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Mad Monk

Active Member
A word of advice to anyone running passive or active LS50's, a sub is absolutely needed!

If you're running passive feed these beasts as much clean high powered current as possible and they will sing at any given volume level.
 
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mseve1

Active Member
So when KEF themselves amplify those speakers for the Wireless II version:

Each tweeter is driven by a 100W class A/B amplifier that delivers a smooth, incredibly detailed treble performance. Dedicated 280W class D amplifiers power the mid/bass drivers,

Essentially using what would need at least 2 x 380W amplifier for passive equivalents it's because they don't know what's required to properly drive their own speakers?

In the LS50 wireless II specs KEF are a bit naughty and do not qualify the advertised 380W power of their active amplification. However since their power supplies are mains rated at only 200W then I would be surprised if the continuous amplifier power rating was any greater than ~150W.
I'm guessing that the quoted figure of 380W is the IHF dynamic rating which is a value that only has to be sustained for 20ms and is typically half the standard continuous rating which is a more reliable measure for comparison purposes.
 
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gava

Well-known Member
In the LS50 wireless II specs KEF are a bit naughty and do not qualify the advertised 380W power of their active amplification. However since their power supplies are mains rated at only 200W then I would be surprised if the continuous amplifier power rating was any greater than ~150W.
I'm guessing that the quoted figure of 380W is the IHF dynamic rating which is a value that only has to be sustained for 20ms and is typically half the standard continuous rating which is a more reliable measure for comparison purposes.

Fair enough, it's still a lot more than 65W though. At any rate I agree that in anything larger than a small room a sub is absolutely necessary.
 
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TB Rich

Active Member
Wish I'd never wasted my time reading Toole and going over pages of Harman research back in the day, blind ABX testing blah yadda blah. All I needed was to speak with TB Rich over at AVforums dishing out the alpha and I would've been 'sorted'.
Have I said something to offend you, kindly point out what I have, or, what I have said that’s so controversial as to offend you and prompt this response? Genuinely, I don’t get where this has come from.

My only posts in this topic were initially to correct the figures 3rdginis was using in the calaculator. Sensitivy being wrong threw the factor out massivley, and 20dB of headroom is unrealistic based on how people set volume and the dynamic peaks above this.
When I responded to your message it was not short or aggressive in anyway.
As I said, KEF in the actives provide enough amplifier power to drive them to a 108dB cleanly, so of course they are going to need a few hundred watts of power. - That doesn’t mean the passives need the same if being driven to sensible listening levels though does it!

Wind your neck in, don’t be rude, and as for “Dishing out the alpha“, hopefully the irony of your comment has not been lost on you!

(Why does Hifi so consistently attract people like you 😔)
 
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rousetafarian

Moderator
Have I said something to offend you, kindly point out what I have, or, what I have said that’s so controversial as to offend you and prompt this response? Genuinely, I don’t get where this has come from.

My only posts in this topic were initially to correct the figures 3rdginis was using in the calaculator. Sensitivy being wrong threw the factor out massivley, and 20dB of headroom is unrealistic based on how people set volume and the dynamic peaks above this.
When I responded to your message it was not short or aggressive in anyway.
As I said, KEF in the actives provide enough amplifier power to drive them to a 108dB cleanly, so of course they are going to need a few hundred watts of power. - That doesn’t mean the passives need the same if being driven to sensible listening levels though does it!

Wind your neck in, don’t be rude, and as for “Dishing out the alpha“, hopefully the irony of your comment has not been lost on you!

(Why does Hifi so consistently attract people like you 😔)
Use the block function as a first step.
 
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