2. amps-preamps
  3. 136604-36148

Amplifier ideas with KEF Reference 1

I'm thinking about pulling the trigger on a pair of KEF reference 1's for my 10'x14' office (currently LS50's). Current electronic setup is all PS Audio (bhk monoblocks, bhk  signature preamp, directstream dac). Incredible sound, zero complaints other than the fact that the monoblocks run hot. I'm getting cooked so the whole ps audio setup is listed for sale.... Although it just may end up at home for a future 2 channel setup!

So with that background, please share ideas for a high quality system that's cool running. Budget up to $15k. I'll add that I favor the warmer side of the spectrum. I'm a bass player and like tight, fast, deep bass..... Glorious mids, and smooth highs. Current ideas to match with the  KEF Reference 1's include:

1. Bel Canto Black EX (integrated or the separates). My contact says the separates are far superior. I'm concerned this setup is too analytical. Anyone heard them?

2. Bel Canto Ref600m. Keep my directstream dac and bhk signature preamp. Probably more than good for an office!?!

3. Hegel 360 or the new forthcoming monster integrated (590)? They're not too pretty to look at but it seems like I've read about hegel and kef being matched at several audio shows. Is there a hegel house sound particularly with the KEF’s?

4. McIntosh mc611. I'll admit it.... I'm a sucker for the looks of McIntosh plus their easy listenability. I've never had ear fatigue listening to a McIntosh setup. I'd be keeping the directstream dac and bhk signature preamp for this combo. Afraid that is be giving up a lot going from the bhk monoblocks to the McIntosh with similar heat. 

5. Luxman L509x. Brand new. Supposed to be very musical and runs cool. I'd probably run with the directstream dac. 

Your thoughts / ideas are appreciated.... Especially if you've heard the recommendation with KEF reference 1's. It's all about system synergy, right!?!

thank you,
ken


keoliphant

Showing 10 responses by georgehifi

georgehifi's avatar
georgehifi
10,312 posts
 

keoliphant OP
I’ve decided to wait for the upcoming Hegel 590 integrated.


This looks better to drive those Kef’s low impedance/-phase angle with in the bass, good choice, and it’s linear not Class-D always better to me so far ("the future is not set").
More output devices and bigger power supply, bodes for better current delivery than the H360 can give, and hopefully will drive that bass of the Kef’s without becoming a bit of a tone control.

"The Hegal H590’s class A/B output is executed by 12 transistors per channel (4 more than the H360) to deliver a very specific 301wpc into 8 Ohms. Hegel’s feed-forward loop wrestles distortion in real time. The power supply inside the H590 is twice the size of that found in the H360"

Cheers George
georgehifi's avatar
georgehifi
10,312 posts
 
keoliphant OP29 posts06-29-2018 12:13pm@georgehifi  can you tell me how the Bel Canto ACI600 Black graph looks?
That's it above Ken, I just called it the Black.

Cheers George
georgehifi's avatar
georgehifi
10,312 posts
 
I still prefer linear amps without the switching frequency noise problems that all Class-D still have, if I needed a integrated linear I like the look of that GamuT Di150 LE I told keoliphant OP to listen to, also the Pass labs Int-250 and I like the well priced John Curl designed Parasound Halo Integrated. 

I haven’t heard the Black but I have heard the 600 mono’s and they are very good, and shows it in the bench tests as well.

1st graph: As far as driving speakers go, the Belcanto 600M’s will drive harder and stay flatter into low impedance speakers than the Belcanto Black can (graphs). Also the 600’s don’t droop in the lows and highs like the Black does. (same graph)

2nd graph: And not that it means much as they are both Stereophile AP filtered, the 600 also has the cleaner 10khz square wave.

3rd graph: And to cap it off the 600’s have lower distortion <-120db than the Black’s >-110db



Belcanto 600m:
https://www.stereophile.com/images/916BC600fig1.jpg
https://www.stereophile.com/images/916BC600fig2.jpg
https://www.stereophile.com/images/916BC600fig3.jpg


Belcanto Black:
https://www.stereophile.com/images/418BC600fig01.jpg
https://www.stereophile.com/images/418BC600fig03.jpg
https://www.stereophile.com/images/418BC600fig06.jpg


Cheers George

georgehifi's avatar
georgehifi
10,312 posts
 
Georgehifi I dont know what you look for you certaintly don't listen to these products.
You assume a lot there sunshine, and the  Bel-Canto Ref 600M sound nothing like Icepower amps, they are one of the finest Class-D's I "have" ever heard, and they nail the Nuforce Ref 9SE V3 which I've also had for a couple of months.
  I could almost live with the Belcanto 600M's, saying that I much prefer linear amps.

Cheers George
georgehifi's avatar
georgehifi
10,312 posts
 
keoliphant OP28 posts06-28-2018 1:20am@georgehifi thanks for the additional suggestions... The load plotting analysis is above my pay grade! Do you know if the Gamut runs cool? That’s paramount for this office setup.

To make sure ask the retailer to have it switch on,, at idle (no music) for an hour before you get there, and feel it. In a small office this should be around the temperature in will be running at.

Looking at the size and density of the heatsinks, should be warm at idle, or low to medium levels, hotter if it’s loud for a period of time.
It say in the review it’s total bias is 14w class-A, 7w per channel this should be warm to the touch. In the bench test when it was run for 1hr with continuous sine wave (RMS) at 1/3 power it got hot, but any linear amp will do this.

Cheers George
georgehifi's avatar
georgehifi
10,312 posts
 
Here are a few integrates that have simulated easy load tests done by Stereophile most don’t become tone controls that you and others have mentioned.

Belcanto Ref600 good
https://www.stereophile.com/images/916BC600fig1.jpg

Lux L509X good
https://www.stereophile.com/images/518L509fig01.jpg

BelCanto Black good (fine plot)
https://www.stereophile.com/images/615BCBfig12.jpg

This T&A V10, didn’t fair too good
https://www.stereophile.com/images/archivesart/V10FIG01.jpg

Ayre AX-5 good (much finer plots)
https://www.stereophile.com/images/713AX5fig01.jpg

Peachtree Nova 300 was good but droops up high.
https://www.stereophile.com/images/517PN300fig01.jpg

Benchmark AHB2 also good (fine graduation plots)
https://www.stereophile.com/images/1115BAHB2fig01.jpg

Cheers George
georgehifi's avatar
georgehifi
10,312 posts
 
I also don’t think that Stereophile uses simulated measurements any more either.
Really?? taken just three days ago.
Again the wavy one is into an easy simulated Kantor load.
And this is what you’ll hear, bad dips at 200hz and 5khz, and peaks at 60hz, 2khz and 10khz.
In other words this amp will sound very coloured (like it’s been EQ’d), because it’s not flat even into an easy speaker load.

https://www.stereophile.com/images/718BP21fig01.jpg
Fig.1 BorderPatrol P21 EXD, 8 ohm tap, frequency response at 2.83V into: "simulated loudspeaker load" (gray, wavy trace).


keoliphant seeing your budget is up to $15k a quick search I would recommend this $12k GamuT Di150 LE integrated amplifier as it gives good current ability and remains quite flat with the simulated load and will also stay reasonably flat with the Kef’s load.
https://www.stereophile.com/images/417Gam150fig01.jpg

https://www.stereophile.com/content/gamut-di150-le-integrated-amplifier



Cheers George
georgehifi's avatar
georgehifi
10,312 posts
 
You take a very scientific approach our approach is via actual listening

Sorry, but I take both. As they are equally important.
And anyone recommending any amp should do also.


Hoping to learn more.
You may get an amp that behaves like a tone control into the Kef's difficult load instead of doing what amps should do, "maintaining a flat frequency response regardless of load variations".
Like this one, the wavy top line is what it’s frequency response is like into an easy "simulated Kantor" speaker load, far from flat!, it will be even worse with the Kef’s as they are harder to drive than the Kantors, this is what behaving like a tone control is meant.
https://www.stereophile.com/images/archivesart/V10FIG02.jpg


Cheers George
georgehifi's avatar
georgehifi
10,312 posts
 
keoliphant OP

These Kefs are not an easy load in the bass, hence some saying they are bright sounding, because amps can’t drive the bass hard enough.

Like I said before, and I have no skin in this like some others, before you buy the wrong amp to do the job or even spend too much.
Ask here or get someone if you don’t know what your looking at, to analyse these two graphs for impedance and phase of these Kefs you have, especially in the bass 50hz-200hz to give you an idea of what amp to buy.
https://www.fidelity-magazin.de/wp-content/uploads/2016/08/1-KEF-Reference-1-Impedanz.jpg

https://www.fidelity-magazin.de/wp-content/uploads/2016/08/2-KEF-Reference-1-elektrische-Phase-1024x...

Cheers George
georgehifi's avatar
georgehifi
10,312 posts
 
keoliphant

They are fairly hard to drive as in the power region of the bass they present a load to the amp of around 3.2ohm and that's broad from 50hz to 200hz.
Look for amps that are happy seeing 3ohms all day as many tube,mosfets, and Class-d may not do the job.
I would hunt out linear amps with beefy power supplies, that use multiple BJT (bi-polar) output devices. Like John Curl designed Parsounds, Krell, D'Agostiono, Gryphon, some Classe's, Mark Levinson. ect 

https://www.fidelity-magazin.de/2016/08/23/kef-reference-1-messungen/

Cheers George
More to discover