SET Asylum

Which SET amp will work well with JMLab 1027Be 91dB efficiency.

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jarek

Hi!
I have brand new JMLabs 1027Be and my listening room is 36sqm big. I tried them with AN Meishu. I loved the sound of 300b more then KT88, and I prefer both 300B and KT88 more then my brand new Krell 400xi which has just 'gone', but my room is too big so I couldn't achieve 'nirvana' for lack of volume (especially old cds sound too quiet). I haven't tried SET based on 211 like Cayin monoblocks or AN Conquest based on 300B.
Can somebody advice which SET amp should work good with my JMLabs and my room? What is the sound difference between 300B and 211?
Thank you in advance for your thougths.
Jarek

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Re: Which SET amp will work well with JMLab 1027Be 91dB efficiency. - astrostar59 15:48:15 02/13/07 (0)
Actually I would like to disagree with some of these comments re power and efficiency ratings. I am using a pair of SET amps rated at 18 watts per side, and into my Zingali 91db efficient speakers (6 ohm, 2 way horn hybrids) it goes plenty loud. My room is 4.5m x 4m.
It may change depending on the speaker model, regardless of efficiency rating, and the size of the tranformers driving the amps, particularly with the ability to shift speaker cones and air pressure. Also larger speakers that are designed with kind loads (typically 2 way, not 3 ways or more), and with simple cross over circuits, perform better with SET than say my old Kef 107/2s which were 92db efficient but not suited to SET in anyway whatsoever!
Best thing would be try before you buy, don't get hooked on text book figures.
Re: Which SET amp will work well with JMLab 1027Be 91dB efficiency. - Paul Joppa 14:09:11 02/13/07 (0)
I found this on the web:
"...The 1027 Be's sensitivity is specified as 91dB and its nominal impedance is 8 ohms, with a dip down to 3.5 ohms at 200Hz..."
The low impedance dip is always a bad sign for use with zero-feedback amps; probably the best compromise would be to use a 4 ohm output tap.
Normally, a minimum power would be estimated as enough to generate 102dB peaks at 1 meter. At 91dB sensitivity,that would be 12.5 watts. But since you will want to use the 4 ohm tap, you'll need double the power, or 25 watts. Your room is larger than the average, requiring more power unless the room is especially reverberant - so your target is probably 35-40 watts. Only a few SETs can approach those levels.
Re: Which SET amp will work well with JMLab 1027Be 91dB efficiency. - djn 14:26:25 02/12/07 (7)
I would try something like this......of course it is mine and I am trying to sell it, but the John Hogan 6SN7/26/300B would really light up your room with those speakers. Cheers.
- John Hogan 6SN7/26/300B amp (Open in New Window)
- Re: Which SET amp will work well with JMLab 1027Be 91dB efficiency. - njjohn 16:17:55 02/12/07 (0)
  Hi Dennis, I was going to say the same thing. If a 300b will work for those speakers, then I would grab that amp at whatever cost.
  (I'll post more about the amp in the thread below when and if I can get the kids to settle down.)
- Aren't you selling that amp? - GEO 16:02:17 02/12/07 (5)
  at 91db in a big room and an impedance that is probably kind at 3.5 min, I would suggest he look for more power. Even a SE KT-88 may be to his liking.....
  - Re: Aren't you selling that amp? - djn 16:11:34 02/12/07 (4)
    Hi GEO, I didn't think about the impedance. Yes I am selling it...don't want to, but business first. I have it hooked up to 16ohms Stromberg Carlsons at the moment and earlier today I hooked it up to my Omega 8ohms and the sound was way down. Not so with the SC, they are plenty loud and really fill the room. I agree with the KT88. At 91, it might be better to go with a PP. Cheers.
    - Omega and the sound was down? - njjohn 16:23:48 02/12/07 (3)
      The super 3's? If you didn't get enough for them, then you must have had the positive and negative speaker wires touching.
      - Re: Omega and the sound was down? - djn 17:05:18 02/12/07 (2)
        
        In Reply to: Omega and the sound was down? posted by njjohn on February 12, 2007 at 16:23:48:
        
        Hi John, The super 3s were down in volume compared to the Stromberg Carlsons. I dont know what the dbs are on the SC but I know the high impedance will make them louder. Cheers.
        
        Thanks everybody for raising your voice. Jarek - jarek 13:11:25 02/15/07 (1)
        
        In Reply to: Re: Omega and the sound was down? posted by djn on February 12, 2007 at 17:05:18:
        
        Thanks a lot, but none of amps mentioned by you is available in Poland as Hi End market is not as matured as I would like :-)
        JArek
        
        Re: Thanks everybody for raising your voice. Jarek - djn 12:21:22 02/17/07 (0)
        
        In Reply to: Thanks everybody for raising your voice. Jarek posted by jarek on February 15, 2007 at 13:11:25:
        
        Hi Jarek, could you buy over the internet and have them FedEx it to you? Or, you could start learning now about a couple great circuits and start building amps for others in your area. Cheers.

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