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Seriously!! 20W for infamous amp killer Kappa 9 in extended bass mode

Discussion in 'Infinity Loudspeakers' started by ccheung, May 2, 2013.

  1. ccheung

    ccheung Member

    Messages:
    52
    I was trying to bi-amp Kappa 9, using 20W 6L6 Push-Pull tube amp to high and 300W SS amp to low. Out of curiosity, I just connected the 20W tube amp to both, and see how it sounds. WOW, very very surprise, it sounds much better than bi-amp. I even used the extended bass mode. Its the best sound Kappa 9 I ever heard. It even has one of the best bass compared to high current SS amp. And I listen loud classical music in a 21'X14' room. The 20W push the kappa 9 without a drop of sweat.
     

     

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  2. koogar519

    koogar519 Active Member

    Messages:
    328
    Location:
    Bloomington Illinois
    So unless I misunderstand what you are saying-- is it-with 200 miiamps you are getting killer sound out of these? AND you are not
    pushing it into non-linear clipping? Basically no dc element to the voice coils?
     
  3. ccheung

    ccheung Member

    Messages:
    52
    Actually it should be less than 20W, cause 20W is mesaure at 8ohm load, and tube 6L6 amp at 4ohm load should be lower than 20W output.

    DC? of course not, Pull-push tube amp has output transformer to block DC even in clipping.

    Clipping? I don't aware of any. I asked my friend who also has a pair of Kappa 9 to come over, and also agreed that they are the best sound Kappa 9 he heard.
     
  4. albowlly

    albowlly AK Subscriber Subscriber

    Messages:
    2,220
    Location:
    SW Ms.
    Blasphemy! You heretic! :D
     
  5. Naptown Rob

    Naptown Rob Ponographer

    Messages:
    5,343
    Location:
    Annapolis, MD
    I love it when somebody tries something just on a lark & the (fabulous) results defy conventional wisdom.:thmbsp:
     
    Quadrunner likes this.
  6. bobrown14

    bobrown14 Super Member

    Messages:
    2,476
    Location:
    Philadelphia, PA
    Good on ya - I've got Infinity QLS-IIIs running them with a SEUL KT-88 tube amp ~13w/ch 4ohm OPTs and they sound mighty fine. Better with tubes than high power SS which I also use for the summer months.

    Cheers,
    Bob
     

     

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  7. dobbhill

    dobbhill Vinyl Addict

    Messages:
    217
    Location:
    Louisiana
    How I got hooked on tubes for Infinity:
    Marantz 8 on top and Crown D75 for bottom on my Gamma's....I rushed out and bought my VTL's and haven't looked back. I have tried big SS on top: I'd rather have underpowered tubes on top. Of course, I've never tried expensive (Krell, Threshold, etc) SS on top, either.
    A Dyna Stereo 70 is pretty sweet, too.
    D
     
  8. srb02

    srb02 "Infinity Speaker" Man Cave Subscriber

    Messages:
    282
    Location:
    Taunton, Mass
    Yup, agree w/ tubes on Infinity's.
    RSIIIA's, not as hard to drive as Kappa 9's, but still not an easy pair by any means.
    if you want Bruce Springsteen or the theme song from Pirates of the Carribbean, than mega SS watts is the way to go.
    EL84 PP amp (15 watts) and female vocals (Leanne Rimes)(lynn Anderson) will bring tears. Totaly different tonal quality to the music.

    My 2 cents Stu
     
  9. ccheung

    ccheung Member

    Messages:
    52
    After heard my pair with tubes, my friend bought dynaco 70 for his kappa 9. He likes it so much and thinking to sell all his ss amps.

    Sent from my Nexus 4 using Tapatalk 4 Beta
     
  10. dumptruck

    dumptruck Lunatic Member

    Messages:
    11,424
    Location:
    Minneapolis, MN
    Alright tubeheads, so what DOES a PP 6L6 amp do into ~1Ω bass impedance? What's the effect? With SS amps, you simply run out of current in a hurry. Is something else happening here?

    [​IMG]
     
  11. Rockyhill

    Rockyhill No marigolds in the promised land Subscriber

    Messages:
    3,200
    Location:
    Maine
    I drive RSb's with a Dynaco ST-35 (now a true 17.5WPC after EFB mod) without any difficulty. And the sound is superb.
     

     

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  12. ccheung

    ccheung Member

    Messages:
    52
    My amps run out of current in hurry? I doubt it. I have mc2 ap750 and carver zr2000. Both are among the best ss amps money can buy for running down to 0.5ohm stable. I'm not saying tube is better than ss in general. I got Genesis IM8300f two weeks ago, their best image and power could only be achieved through SS. It all about matching. I believe many earlier infinities were designed with big power tubes in matching. Without big power tubes, low power tubes may be the second choice rather than ss.

    Sent from my Nexus 4 using Tapatalk 4 Beta
     
    Last edited: Jul 6, 2013
  13. dumptruck

    dumptruck Lunatic Member

    Messages:
    11,424
    Location:
    Minneapolis, MN
    I was talking about an SS amp of equivalent power rating, but I think you're missing my point.

    The Kappa 9 are rated at 101dB/1W/1m. They don't say how they took that measurement, but regardless it would imply that only 2-3V is probably needed for very satisfying output in many situations. That's hardly any power, even if you figure the phase angle is not so nice. It is a significant, but not crazy amount of current. So, if a dinky SS amp sounds bad (or dies), but the 6L6 PP does fine, why, and what's the difference?

    I posted it as a question because I really don't know that much about amps and others around AK know a lot. There should be nothing mysterious happening here, since we have a fair amount of information, except OT rating and output impedance of the tube amp.
     
  14. charles 1973

    charles 1973 Super Member

    Messages:
    3,059
    "I was talking about an SS amp of equivalent power rating"

    A few factors come into play here I believe. One is that Tube Amps have a much lower Damping factor than a SS Amp. This can produce a fuller, more noticable Bass responce in some speakers with the same power. While I generally believe DF over 50 - 100 make little difference, from 5 - 100 might very well.

    Tube Amps often have a dedicated 4 ohm Tap for the speakers. While many SS Amps will work into 4 ohms, there not optimized for it like the Tube Amp to make it more stable into a speaker like this. SS Amp's can oscilate and self distruct in short order under this condition. It's not just about Current requirements.

    Also Tube Amps Soft Clip, Permitting Them to Play perhaps 3 db Louder than their SS counterparts (although I don't recomend trying it with home systems), and up to 6 db or more in commercial applications if necessary, where clipping the SS Amp would quickly fry the speakers.

    Just thinking out loud, I use a SS Amp myself, but researched Tube Amps before I bought it. It could simply be that the Tube Amp is a better Amp, despite the difference in power output. Power is the last thing I look for in a quality Amp. IMO 25 - 50 wpc should bring most speakers, including the Kappa 9's to very satifying SPL's if they can handle this complex a load, and your pretty close to that.
     
    Last edited: Jul 6, 2013
  15. EPI-Center

    EPI-Center Super Member

    Messages:
    2,477
    Location:
    North Shore Mass
    so I am safe to run my kappa 8's from a Fisher 500c?
     
  16. Arkay

    Arkay Lunatic Member

    Messages:
    19,966
    Location:
    Hong Kong
    I can see where this could be heading: a whole new, long list of amps being tried with Kappa 9s. Some successfully, others... well, there might be a bunch of Kappa 9 parts in Barter Town one day soon. :D


    I love driving Infinities with tubes, at least on the top end. It's how they were "voiced" by the designer, and I think the clarity and extension of the EMITs (and EMIMs) brings out the best of "tube sound", without the harshness/shrillness that some (not all!) SS can have. I did try driving the Quantum 2's with a Chinese-made tube amp before, and it seemed to handle the Watkins woofers well enough. I never really cranked it up much, though, out of fear of causing harm, and soon switched to bi-amping with SS on the bottom. It was a fairly robust (68 "tube watts", IIRC) push-pull design using EL34s. I know some people have recommended Mac amps for Infinities, because of the autoformers. Clipping is the enemy, and such amps tend not to clip. They also, as noted above, tend to prevent DC output.

    Haven't heard of anyone using low-power tube amps to drive big Infinities, and I'd be surprised if it is entirely safe/wise/recommended. But heck, anything is possible, if the physics underlying it are right. I don't know enough (without a LOT of thought and probably research) to know exactly what would be going on here. Will be watching this thread with interest!
     

     

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  17. bobrown14

    bobrown14 Super Member

    Messages:
    2,476
    Location:
    Philadelphia, PA

    I've been running my QLS-III's with a Keggerized SEUL 6L6 single ended amp for a pretty long while now in my shop daily driver. Amp puts out about 8w/ch and sounds GREAT and I've cranked it up some but not regularly. Woofers are fine sound good with no boomy out of control sound. I like the sound mighty fine. I don't take it up to clipping tho, thats not a good idea.

    Cheers,
    Bob
     
  18. Ken Boyd

    Ken Boyd AK Subscriber Subscriber

    Messages:
    16,243
    Location:
    Florida
    I used my Fisher on a pair of Infinity QLS-2's for a little while, one CD and by the time it finished playing that CD it was quite hot.
     
  19. bobrown14

    bobrown14 Super Member

    Messages:
    2,476
    Location:
    Philadelphia, PA
    I forgot to metion my little SEUL 6L6 amp has 4Ohm OPTs which help a lot. Doesn't even break a sweat really.

    Cheers,
    Bob
     
  20. Odysseous

    Odysseous New Member

    Messages:
    25
    Location:
    San Antonio, TX
    I have ran my Kappa 9s with Bob Carver's new 305 watts tube mono blocks and they sound amazing! I've also ran then with 50 watts solid state McIntosh receiver from 1975 and they sound great too.
     

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