Welcome to the AudioShark Forums.
Results 1 to 11 of 11
  1. #1
    Junior Member
    Join Date
    Jul 2024
    Location
    Austin
    Posts
    2

    KEF Reference 1 Meta with Class A amp

    Hello all.

    I have a Sugden integrated amp which runs pure Class A.
    The specs show 40 watts into 4 ohms and 30 watts into 8.

    My question is do you think this amp will run the KEF Reference 1. It’s rated 85-86 db sensitivity with nominal impedance at 4 ohms.

    They will be placed in a relatively small room and I generally listen at about 80-85 decibels.

    I understand the amp is underpowered in a technical sense but does Class A even the playing field.

    P..S. This amp creates more than enough power for my Merlin floorstanders which are 89 db efficient.

  2. #2
    Senior Member
    Join Date
    Nov 2013
    Location
    St. Louis, MO, USA
    Posts
    3,147

    Re: KEF Reference 1 Meta with Class A amp

    If your posted specs are correct it looks like your amp prefers 4 ohms and 40 watts should be enough, often it's more the current availability more so then watts anyway in driving lower impedance.

    Welcome to AS
    Aurender ACS10 w/Audioquest Diamond USB, Esoteric N05xd
    Mark Levinson #526, 534 & JBL 4367's
    Clearaudio Performance DC w/Maestro cart
    Clarus Concerto & their Crimson cables

    HT: Marantz AV8003, Linn 5125, JBL SAM3ha, Revel s30,
    SVS PC13 Ultra
    Transparent, Analysis Plus & Tributaries. PS Audio filtering
    Sony XBR-75X940D & BDP
    Parasound P6, MBL 8006b, Artisan speakers/subwoofer

  3. #3
    Senior Member
    Join Date
    Apr 2017
    Location
    Central FL
    Posts
    806

    Re: KEF Reference 1 Meta with Class A amp

    Welcome!
    Main System - Lumin U2, Modwright LS36.5 DM Preamp, VTV Purifi 1ET-7040SA with tube buffer, EMM Labs DAC 2X (ver. 2), Torus RM-20, Thiel CS 3.7s, 2 Rel S/812 subs
    Back-up 1 - Premium Audio mini Gan Amp, Oppo 103D, 2 Richard Gray cond, Selah SA-2s, Sumiko S5 sub, Teac UD-503 DAC, Carver (modded) C-9
    Back-up 2 - Onkyo TX-NR797, Panasonic DP-UB820, Vansevers cond, B&W P6s, PowerSoundAudio S1500 sub

  4. #4
    Senior Member
    Join Date
    May 2020
    Location
    UK
    Posts
    559

    Re: KEF Reference 1 Meta with Class A amp

    Quote Originally Posted by Tomster66 View Post
    Hello all.

    I have a Sugden integrated amp which runs pure Class A.
    The specs show 40 watts into 4 ohms and 30 watts into 8.

    My question is do you think this amp will run the KEF Reference 1. It’s rated 85-86 db sensitivity with nominal impedance at 4 ohms.

    They will be placed in a relatively small room and I generally listen at about 80-85 decibels.

    I understand the amp is underpowered in a technical sense but does Class A even the playing field.

    P..S. This amp creates more than enough power for my Merlin floorstanders which are 89 db efficient.
    Can I ask which Sugden amp you have? I ask because their Masterclass FPA-4 was amongst the dozen amps I home demo'd with my own speakers when I was moving from tube amps to ss. Although I was expecting a Class A to win me over, sadly the Sugden was one that seriously disappointed, though your amp may well be better with your speakers.

    My own view is that the primary item that needs careful selection to suit your room and listening preferences is speakers, and only then should you be looking for the ideal amp to power those speakers. That's why I was demo'ing all those amps. These included other Class As (Accuphase A-36, etc) and a number of Class AB and D. The best Class A was the Accuphase, but it was just a little too "polite" so I reluctantly sold it after a year or so.

    Whether Class A is likely to get the best from the KEF, I would suggest unlikely in my view, although the only Sugden I've had first-hand experience with is the FPA-4. Do you really like Class A or the Sugden in particular?

    Have you bought the KEFs yet? If so, you can answer your primary question (is the Sugden powerful enough) without our help, but I suspect it will be. However if you are still deciding on your speaker purchase, I would suggest you give preference to this decision over the suitability of an existing amp.

    PS - The only KEFs I've owned were the big Reference 107s (from the mid 1980s) and great speakers they were. Sensitivity was 90 dB and impedance 4 ohms. I had 100 watt mono amps at the time, but I learned (after selling the speakers) that those speakers needed an amp with greater current delivery than my AVIs could deliver. So I probably never heard the speakers at their best! This experience has contributed to my view that speakers need to be chosen first, then get the best amp to power them.
    Sources - NAD M50.2 (streamer, CD player, CD ripper, hard drive music store)
    Amplification - NAD M33 all-in-one, NAD M12 preamp (in reserve), Atma-Sphere Class D monos
    Speakers - Avantgarde Duo XD, Avantgarde Duo (2006) - both aesthetically modified

  5. #5
    Senior Member
    Join Date
    Sep 2017
    Location
    Boynton Beach, FL
    Posts
    1,029

    Re: KEF Reference 1 Meta with Class A amp

    My KEF ref 5's love being over powered and sound best when they are.


    Sent from my iPhone using Tapatalk
    Preamp/Digital: Meitner MA3
    HT Processor: Bryston SP3
    Amps: Bryston 14b3, Bryston 4b3
    Speakers: Kef Reference 5, Kef Reference 4c
    Sub: REL Carbon Special
    Power: Shunyata Denali, Bryston BIT15
    Wires: Wireworld Silver Eclipse XLR & SC, Ethernet - WW Platinum USB
    Other: Stillpoint Ultra SS, ISO-Acoustics ISO Pucks

    -Kyle

  6. #6
    Junior Member
    Join Date
    Jul 2024
    Location
    Austin
    Posts
    2

    Re: KEF Reference 1 Meta with Class A amp

    Quote Originally Posted by Phishphan View Post
    My KEF ref 5's love being over powered and sound best when they are.


    Sent from my iPhone using Tapatalk
    Well I typed out a lengthy response but for some reason it didn’t post and now it’s gone.
    The Readers Digest version is my amp is the Sugden A21se.

  7. #7
    Senior Member
    Join Date
    May 2020
    Location
    UK
    Posts
    559

    Re: KEF Reference 1 Meta with Class A amp

    Quote Originally Posted by Tomster66 View Post
    Well I typed out a lengthy response but for some reason it didn’t post and now it’s gone.
    The Readers Digest version is my amp is the Sugden A21se.
    I think that Sugden's A21 series has stood the test of time and it has a lot of fans. I suspect that the "higher spec" and more costly Masterclass FPA-4 that I had on loan wasn't popular as it seems to be discontinued now as it's not in their main website, although a Google search comes up with a Sugden page describing it as "the latest member of the Sugden Masterclass Family." How odd!

    I'd still keep an open mind after buying your new speakers whether to stick with the Sugden or use a different amp. It's well worth trying a few options, including Class D. Rather against my expectations when I tested a dozen ss amps, I found the best of the Class D amps offered the best sound out of all of them - perhaps tied with the GamuT D200 Mk III (Class AB). Good luck anyway.
    Sources - NAD M50.2 (streamer, CD player, CD ripper, hard drive music store)
    Amplification - NAD M33 all-in-one, NAD M12 preamp (in reserve), Atma-Sphere Class D monos
    Speakers - Avantgarde Duo XD, Avantgarde Duo (2006) - both aesthetically modified

  8. #8
    Senior Member
    Join Date
    Nov 2013
    Location
    St. Louis, MO, USA
    Posts
    3,147

    Re: KEF Reference 1 Meta with Class A amp

    I found an old Stereophile review of the A21 where it was mentioned the amp could drive Quad ESL's which have a very difficult load due to impedance and, in fact, Sugden uses the Quad's as a listening reference. Then I found information that says the A21se has double the power supply of the standard model. So I've never owned the Sugden but I'd say it would drive the Ref 1 with no issue.

    Decibels are logarithmic however the Merlins's will play nearly twice as loud with the same signal input. If you have plenty of volume left when listening to the Merlin then this may not be an issue for you with the Ref 3.
    Aurender ACS10 w/Audioquest Diamond USB, Esoteric N05xd
    Mark Levinson #526, 534 & JBL 4367's
    Clearaudio Performance DC w/Maestro cart
    Clarus Concerto & their Crimson cables

    HT: Marantz AV8003, Linn 5125, JBL SAM3ha, Revel s30,
    SVS PC13 Ultra
    Transparent, Analysis Plus & Tributaries. PS Audio filtering
    Sony XBR-75X940D & BDP
    Parasound P6, MBL 8006b, Artisan speakers/subwoofer

  9. #9
    Senior Member
    Join Date
    Mar 2017
    Location
    chicago burbs
    Posts
    631

    Re: KEF Reference 1 Meta with Class A amp

    It confounds me that I can use less than a single watt peak yet hear an obvious difference between a 300/525 wpc amp and 600 wpc amp? 1 would think such a small draw would make amps impossible to tell apart. There’s obviously more to an amp than its wpc output. If the model 1 reference is anything like the Blade you’ll know pretty quick.
    KEF Blade, Mc-611's, C49 rega jupiter, roon nucleus, revox tuner. Meridian dsp8000 se upgrade, meridian 218 zone controller VA Beethoven's, Hegel h360.

  10. #10
    Senior Member
    Join Date
    Mar 2017
    Location
    North Carolina
    Posts
    819

    Re: KEF Reference 1 Meta with Class A amp

    Quote Originally Posted by Tomster66 View Post
    Hello all.

    I have a Sugden integrated amp which runs pure Class A.
    The specs show 40 watts into 4 ohms and 30 watts into 8.

    My question is do you think this amp will run the KEF Reference 1. It’s rated 85-86 db sensitivity with nominal impedance at 4 ohms.

    They will be placed in a relatively small room and I generally listen at about 80-85 decibels.

    I understand the amp is underpowered in a technical sense but does Class A even the playing field.

    P..S. This amp creates more than enough power for my Merlin floorstanders which are 89 db efficient.
    These speakers' efficiency is on the low side. What kind of music do you listen to? If it's classical and your 80-85dB is an average listening level, my answer would be 'no.' You would get sound, but dynamics would be compromised.

  11. #11
    Senior Member
    Join Date
    Nov 2015
    Location
    Kansas
    Posts
    5,961

    Re: KEF Reference 1 Meta with Class A amp

    I have had KEF speakers since the early '80s. I have driven with both SS (First Watt) and tube (Audio Mirror) Class A. Never an issue... but I don't ever approach concert levels . If you like to play at modest levels to lower-high levels then you should be fine. I would love to get a pair of Ref 1's.
    McIntosh C49, MC152, MR85, R778 | T+A DAC 8 DSD | KEF LS50 Meta w/S2, KC62 (x2) | Rega RP8, Ania Pro, NEO PSU | Technics SL-1500C | Audio Technica VM750ML | Hexmat Eclipse, Yellow Bird, Molekula, Molekula Mini | Pro-Ject VC-E | Falcon NW PC Server (Roon Core & HQPlayer) | Microsoft Surface Pro 6 (Roon Controller) | Wyred 4 Sound ISO Recovery, DC Recovery | Abyss Diana Phi | Schiit Mjolnir 3 | Astell&Kern SE200 | Oppo BDP105

    “One of the great challenges in life is knowing enough to think you're right but not enough to know you're wrong”
    "You can't use reason to convince anyone out of an argument that they didn't use reason to get into"
    ― Neil deGrasse Tyson

AudioShark - The Best High End Audio Discussion forum.

AudioShark forum is a leading forum site for High End Audio Discussion, Stereo System Discussion, Home Theater System Discussion, Best Home Stereo System Discussion, Home Theater Installation Discussion etc.

The AudioShark forum was created for sharing the passion of high-end Audio. We have Audiophiles from all over the world participating and sharing their knowledge. From novice to experts, you will find a friendly environment for discussing about High End Audio, Stereo System, Home Theater System, Home Stereo System, Home Theater Installation, Amplifiers, Speakers, Subwoofers, Integrated System, Acoustic treatments & Digital Room Corrections and many more.

At AudioShark, we also have incorporated an exciting Marketplace where members can peruse terrific buys on used gear, as well as meet dealers and discuss the purchase of new gear.

We are as crazy about this hobby as you are! So come on in and join us! Audioshark.org the Friendliest Audio Forum!

Industry Participation Disclosure : The owner and administrator of Audioshark is the owner of Suncoast Audio LLC in Sarasota Florida. Suncoast Audio has a full brick and mortar presence in Sarasota with several great show rooms with many world class brands. More information can be found at http://www.suncoastaudio.com

Audioshark is a community of like minded individuals. Audioshark welcomes participation from all manufacturers and owners of all brands and products. It is our belief that online forums provide a community of like minded audiophiles and music lovers to encourage the growth of this wonderful hobby.

Sincerely,
The Audioshark.org Team

KEF Reference 1 Meta with Class A amp

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •