Donald North Audio — Owners Thread

Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by Huxleigh, Aug 12, 2016.

  1. Xecuter

    Xecuter Brush and floss your amp twice a day

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    @Claud have you tried many NOS 2a3? I've been curious about the Acme for awhile. Just haven't seen any reviews to get me to pull the trigger.
    Have you tried spring top 2a3, or fivre/arctarus? Have you tried the double mono plates??
     
  2. Claud

    Claud Acquaintance

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    At the moment, that is a spring top or fishing pole RCA 5U4G in the Stratus as rectifier for my Acmes. I have several 5U4Gs that are/were NOS. I am still breaking in the Acmes. The system sounds very nice . I like to start tube rolling after I have determined a good base combination of tubes. That is why the rectifier is key. If I don't get any other recommendations , I will just buy a EML 5U4G and start from there. If its good enough for Ruby Tiger, its good enough for me.
     
  3. Claud

    Claud Acquaintance

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    Yes. I have four sets of NOS 2A3s two RCA one early 40s Sylvania and one Tung Sol. My best sounding RCA pair is spring top.
     
  4. Claud

    Claud Acquaintance

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    [​IMG]
     
  5. Claud

    Claud Acquaintance

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    For those interested in Psvane Acme Supreme 2A3s, you can order from Grant Fidelity. You can order a "select" pair or just a regular pair that is cheaper. Grant's packing is first rate. The tubes are solidly encased in foam.
    [​IMG]
     
  6. allegro

    allegro Friend

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    @Claud suggest you use free imgur.com to host your photos to get rid of that annoying photobucket watermark.
     
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  7. Claud

    Claud Acquaintance

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    Thank you. Have not used Photo Bucket in years. Yea, I have got to switch.
     
  8. Claud

    Claud Acquaintance

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    Started breaking in my EML 5U4G this morning and putting another 100 hours on my Acme 2A3s. By Wednesday I should be ready to switch stock 6N1P for a RT select and enjoy the Stratus again. Is it just me or is that EML twice as big as a normal NOS 5U4G like the NOS RCA I switched out?
     
  9. Claud

    Claud Acquaintance

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    [​IMG]
     
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  10. saint.panda

    saint.panda Acquaintance

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    For power tubes, interestingly I find the KR to be a better match (more musical) than the Sophia Carbon Princess 300B 2.5V. Was expecting the latter to be smoother and better match. The KR really is a good tube for the Stellaris despite being a current production tube.
    Having a Pavane instead of Yggdrasil would probably be an even better match for the Focal.
     
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  11. m17xr2b

    m17xr2b Friend

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    The 300B is biased far too cold considering the Stellaris operating point for it to sound good. Nevermind that I find the regular Carbon Princess 300B mediocre at best. The Royal Princess is in a different class.
     
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  12. m17xr2b

    m17xr2b Friend

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    I know myself but I don't know my enemy. And he is fierce:
    [​IMG]

    Meet my new PX4 amplifier:

    [​IMG]

    A different animal to the 2A3 valve, on the same level for sound with the AVVT, fuller low end and midrange with better treble extension. This sounds more refined and classy, full of fineness and capable of unpacking all the layers of the music.

    Stellaris cannot use PX4 as is and while sound will be made you'll shortly destroy these delicate tubes.

    I had to change the DC heater boards, still have some fine tuning to do, currently it's at 3.9V, a 2.5% difference, well within spec.

    I've biased them at around 40mA, 10.5W dissipation with a 5U4G/U52 and 11.8W on 422A. This version is 15W max.

    Modern PX4 such as AVVT,EML,KR cannot be used without further modifications.
     
    Last edited: Aug 9, 2019
  13. Claud

    Claud Acquaintance

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    I think the KRs are great too. I use a WE 422a with them and it was the best sound I had gotten out of my Stratus until I went with the Acme 2A3s and EML 5U4G. I also bought a used pair of the Carbon Princess and like the rest of you, I think they are nothing special.
     

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