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    My KT120 / M-125's

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    Dahlberg

    Posts : 110
    Join date : 2016-09-27
    Age : 56
    Location : Sweden

    Re: My KT120 / M-125's

    Post by Dahlberg on Wed Jan 11, 2017 8:36 am

    And the winner is, the 4ohm tap. On my speakers the bass resolution is a lot better on this tap, the 8ohm tap results in a loose and boomy bass. There is no difference in hum level, still 3,5mV on cold power transformers. It rises to 5mV when the amps have been playing for a couple of hours and have reached there top temperature.
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    Dahlberg

    Posts : 110
    Join date : 2016-09-27
    Age : 56
    Location : Sweden

    Re: My KT120 / M-125's

    Post by Dahlberg on Fri Feb 10, 2017 7:44 pm


    Dogstar

    Posts : 289
    Join date : 2014-06-23

    Re: My KT120 / M-125's

    Post by Dogstar on Sun Feb 12, 2017 11:04 pm

    Cerakote is a hardened coating popular in the firearms industry. It requires baking the components that were painted and it's supposed to be a durable finish...I may give it a try on an aluminum amp chassis I am finishing. Cerakote works on aluminum, steel and plastic according to the web site. You just don't bake the plastic.
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    bluemeanies

    Posts : 200
    Join date : 2015-02-09
    Age : 67
    Location : Folsom Pa.

    Re: My KT120 / M-125's

    Post by bluemeanies on Sat Feb 25, 2017 10:00 am

    Beautiful job...you certainly are talented.
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    fredeb

    Posts : 4
    Join date : 2017-04-22

    Re: My KT120 / M-125's

    Post by fredeb on Mon Apr 24, 2017 10:49 pm

    Absolutely beautiful ! You obviously know what you're doing . Smile

    Are those Nelson Pass slot loaded open baffles ( SLOBs ) for bass ? Stunning !
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    Dahlberg

    Posts : 110
    Join date : 2016-09-27
    Age : 56
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    Re: My KT120 / M-125's

    Post by Dahlberg on Tue Apr 25, 2017 3:18 pm

    Thanks Smile  The subs are open baffle but I would describe them as a
    cross between the subs fro Audio Artistry "beethoven" and the "ripole"
    project. Most likely one of the most cost ineffective ways to achive
    true subsonic output. They run of a pair of "Hypex ucd2K" amps
    @ 16ohm. 1,5kw and some serious amount of dipole compensation.
    It sounds great and it's getting even better (I belive) from a total
    rebuild of the digital xo/dsp system. I'm leaving dsp (iir) and instead
    I'm going for a pc based (fir) filter solution from "Acourate" and some
    new hardware on the computer side. It has been quite a mouthfull and
    then some, but I'm slowly getting there. Cool

    The amps sound great, now I'm running new Sovtek 12au7 tubes on both
    positions, not absolutely sure what I like most so I might try the cleartops
    again in the first position.
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    fredeb

    Posts : 4
    Join date : 2017-04-22

    Re: My KT120 / M-125's

    Post by fredeb on Wed Apr 26, 2017 7:41 am

    Your system is certainly looking absolutely like the best anyone could ever yearn for . I guess the Accourate solutin provides x-over frequencies, phase correction and levels . Where you using mini-dsp before ?

    12au7's are definitely one of my favourites in this configuration . Along with E182CC and 6N6P ( both require re-wiring ) .

    Thanks for sharing your experience with us . Smile
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    Dahlberg

    Posts : 110
    Join date : 2016-09-27
    Age : 56
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    Re: My KT120 / M-125's

    Post by Dahlberg on Wed Apr 26, 2017 11:41 am

    "Acourate" does it all. XO, linear phase (fir) filters, driver linearization,
    time delay, room correction and so on... I'm still using the "Najda" dsp
    that actually works great.  Embarassed  On the other hand I believe that for going
    to the next level of performance, linear phase filters is where I will
    get the highest payoff. The number of "taps" I will need is not
    available in any dsp chip of today so therefore the pc solution.

    I also like the 6n6p and I'm using them in two of my output dac buffers, together with 6n30p.

    Acourate

    A tutorial

    The other half
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    fredeb

    Posts : 4
    Join date : 2017-04-22

    Re: My KT120 / M-125's

    Post by fredeb on Wed Apr 26, 2017 1:53 pm

    Very interesting , I briefly gleaned over " the other half " , I'll look at it all properly this weekend , when I have some time . And look at your site too .

    Thanks again ! Very Happy
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    Dahlberg

    Posts : 110
    Join date : 2016-09-27
    Age : 56
    Location : Sweden

    Re: My KT120 / M-125's

    Post by Dahlberg on Wed Apr 26, 2017 3:17 pm

    The site hasn't been updated in ages Embarassed and the diy articel on the ribbon driver
    could also need some adjustments.
    At some time there will at least be some more up to date pictures in the "Diy gallery",
    these ones are at least 10 years old.
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    bluemeanies

    Posts : 200
    Join date : 2015-02-09
    Age : 67
    Location : Folsom Pa.

    Re: My KT120 / M-125's

    Post by bluemeanies on Fri May 12, 2017 7:18 am

    Dahlberg wrote:The site hasn't been updated in ages  Embarassed and the diy articel on the ribbon driver
    could also need some adjustments.
    At some time there will at least be some more up to date pictures in the "Diy gallery",
    these ones are at least 10 years old.



    Just wanted to drop a line to say you did a stupendous job in assembling these 125's not to mention the artistic design you encased them in with that beautiful wood.
    Good tools...absolutely, talent no doubt!

    Good job and thanks for posting pictures.
    blue
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    Dahlberg

    Posts : 110
    Join date : 2016-09-27
    Age : 56
    Location : Sweden

    Re: My KT120 / M-125's

    Post by Dahlberg on Fri May 12, 2017 1:20 pm

    Thanks.  Smile
    For now the tungsol 12au7 input tubes will be left in place, they deliver a solid
    performance and are (almost) dead quite when they schould be.
    Got a mail that there is some parts I have been missing on the way for the dsp project today  Very Happy  Very Happy  Very Happy  Very Happy
    On the other hand it's almost summer Shocked  and time for barbecue and beers soo.... lol!
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    Sabciu

    Posts : 1
    Join date : 2017-05-17

    Re: My KT120 / M-125's

    Post by Sabciu on Wed May 31, 2017 2:50 pm

    Dahlberg wrote:I could not help myself so I had to see how it looked with tubes in place. It turns out a bit lighter on camera then it looks.  Very Happy


    Hi There! I love what you did with the M-125 Amps! Shocked I'm putting mine together right now. I was wondering where you sourced the Circuit Card Cover?? I could sure use a couple. The really finish off the Amp quite nicely. Can you point me in the right direction or reproduce for purchase??

    Thanks!
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    Dahlberg

    Posts : 110
    Join date : 2016-09-27
    Age : 56
    Location : Sweden

    Re: My KT120 / M-125's

    Post by Dahlberg on Sun Aug 13, 2017 6:55 pm

    Well now summer is almost over so... Cool Sorry but I can't help out
    with the pcb covers, maybe someone else on this site has the
    possibility ? Why not ask again in a separate thread ?
    In retrospect I would have liked a consept with just a top plate
    ment for wood frame mounting to start with (and a pcb cover).

    Dogstar

    Posts : 289
    Join date : 2014-06-23

    Re: My KT120 / M-125's

    Post by Dogstar on Wed Aug 23, 2017 10:13 am

    Usually I don't like the wood frame/metal plate chassis but the red transformer bell covers and PCB plate makes your amp look very nice.
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    Dahlberg

    Posts : 110
    Join date : 2016-09-27
    Age : 56
    Location : Sweden

    Re: My KT120 / M-125's

    Post by Dahlberg on Wed Aug 23, 2017 4:11 pm

    Thanks, I'm waiting for a set of "Audyn cap-true copper 0,22uf " to try in place of the K40's. Will see how that turns out.
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    Dahlberg

    Posts : 110
    Join date : 2016-09-27
    Age : 56
    Location : Sweden

    New caps

    Post by Dahlberg on Tue Nov 07, 2017 7:17 am

    So finally I got some time to mount the "Audyn true copper max" capasitors, great succes Very Happy
    These are some really nice coupling caps. Nice warm tone and still very open in character.
    A bit difficoult to work with though, conections are litz wire that doesn't fit directly to the
    pcb solder hole diameters.
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    Dahlberg

    Posts : 110
    Join date : 2016-09-27
    Age : 56
    Location : Sweden

    Re: My KT120 / M-125's

    Post by Dahlberg on Mon Nov 13, 2017 8:41 pm

    Ok, so now I have tried the "gz-37 rectifiers as well. I wouldn't say that it was a "slam dunk"
    but it wasn't that far of... I lost some definition in the bottom but the level of presence and musical
    involvement I have right now is just Shocked scratch Very Happy

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