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Amps for KEF Blade 2

I am looking for advice from owners or dealers of the KEF Blade 2 loudspeakers. I am concerned my current pair of amps will not be sufficient for the B2s because of an article written about the original Blades published on July 5, 2013 in The Absolute Sound:

"The Blades have a nasty kick in their crossover that will suck an amplifier dry quicker than a student downing free tequila shots ... Just don’t be tempted to cheapskate on the driving amps, or you’ll live to regret it. Tube amps at least have an output transformer to hide behind, but when the Blades suck out a solid-state design, they celebrate by spotlighting their tweeter something chronic. To give you some idea of the lengths required, the otherwise excellent Rowland 625 [550 watts into 4 Ohms] wasn’t up to the job, it taking a pair of the 725 monoblocs [650 watts into 4 Ohms] to restore order. "

Are the Blade 2s just as demanding as the original Blades in terms of amplification? I would guess not due to the smaller 6.5 inch woofers, but this is just an uneducated guess. I own a pair of Benchmark AHB2 amps, which according to the manufacturer produce “a little over 500 watts into 4 Ohms”. Will this be enough?
e91811
e91811 OP
26 posts
 
Thanks mmeysarosh for the informative post. I decided to contact Benchmark about their AHB2 amps driving the KEF B2s and this is what they wrote back to me:

"This is from engineering. This is actually a very easy speaker to drive in mono mode. It is a nice design with well-controlled impedance curves. There will be 6.0 dB more headroom in mono mode with this speaker. The AHB2 will have current to spare when driving this speaker in mono.

Max SPL in mono is 115.9 dB (ignoring power compression)
Max SPL in Stereo is 110.1 dB (ignoring power compression)

Typically you will need to subtract a dB or 2 to account for power compression."

It’s been a very long time since I took college physics so I can’t say I thorougly understand everything that the both of you wrote, however, I do understand "current to spare"! In conclusion, I’m still not sure if the B2s are easier to drive than the original Blades but, it appears my amps will be able to handle the B2s so I suppose I should be satisfied with that answer.

mmeysarosh
126 posts
 
I did see some of the specs on their website and they do specify increasing power output at 3 ohm load, which indicates amplifier design with current capability in mind.

While the the power output isn't able to drive the speaker to its max SPL, my take being that you'll give up before either amp or speaker do.

Overall it sounds as if you have a capable partner. I brought up some of those ASP1000 class D amps as they doubled output going from 8 to 4 ohm impedance, but quickly fell apart anywhere below that. The speaker in question was the Revel Salon2, which is also current happy design with lower efficiency in comparison to the B2. So you really want to get a clear answer if the design can dip to 3 ohm or even 2 ohm. Which is was you do have with your current amp.
 
theothergreg
222 posts
 
When I auditioned the Blade 2, it was paired with a Chord SPM 5000 and did it quite well.  If you want an amp stable to 1 ohm, you can look at the Electrocompaniet Nemo monoblocks.   Those can drive anything you can throw at it.
yyzsantabarbara
4,808 posts
 
e91811,

It has been a year since the last post here. I was wondering how you liked the AHB2 with your Blade 2? What is the rest of your system?

I am all over the map on DAC | Pre | Amp choices for the Blades (for my living room). I am going to try and listen to the Theta Prometheus, Bryston 7BSST3, and the AHB2 with the Blades . If I go this route I am thinking of something like a Briscati M12 (includes DAC + analog volume + soon to be Roon Ready via ethernet).

The other option which I think will definitely work great is getting high quality separates for the Blades. However, there will be a substantial increase in costs doing this. Your approach of using the AHB2 is something I thought might be a way to get around high cost amps for the Blades.
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dbphd
1,628 posts
 
I've been planning for Blade 2s when I consolidate my two setups.  I plan to keep either the new Ayre VX-5 Twenty (175@8Ω, 350@4Ω) or the Parasound JC1 monoblocks (400@8Ω, 800@Ω) and use an integrated for the LS50s.  Will either of those amps have trouble driving Blade 2s?  I use the VX-5 with a KX-5 Twenty preamp and the JC 1s with a JC 2 BP if that's relevant.

db
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