DIY Power Amplifier Advice Thread

Discussion in 'DIY' started by Vansen, Sep 10, 2017.

  1. Vansen

    Vansen Gear Master 2.0

    Staff Member Friend
    Joined:
    Nov 19, 2016
    Likes Received:
    878
    Trophy Points:
    93
    Location:
    NYC-ish Area
    Since we don't have a thread dedicated to general DIY power amplifier discussions, I figured I would start one...

    Some time next year, I'm moving back west and I'll be far closer to my father. Following my move, I plan to build a set of speakers and an amp. For the speakers, I'm heavily considering the Nagaoka D-37 mkIII plan that @JK47 and @struggles used. Regardless of whether or not I use Nagaoka D-37 mkIII plan, my speaker requirements will be as follows: minimum of 94.5 dB/w/m, highly resolving at low volume levels, plays nice in a small room (regular den/ bedroom).

    I'm looking for suggestions on DIY amp designs that will play nice with those speaker requirements. I don't have the electrical knowledge to spearhead a project like this on my own, but my father spent most of his career as an electronics R&D engineer, and certainly does. This'll be a nice learning experience for me and will give me solid quality time with my father.

    The basis of what I'm looking for are:

    Low watt output is preferred
    BJT amplification, no FETs
    No coupling capacitors
    20 to 20kHz response: -0.1 db
    2 to >= 45kHz response: -3.01 db
    Constant phase shift over 20-20kHz (provided phase shift is listed)

    ...these specs look a fair bit like the new Vidar out there. Also, banning MOSFETs from the design eliminates Nelson Pass designs.
     
    JoshMorr, philipmorgan and JK47 like this.

  2. Hrodulf

    Hrodulf MOT: Sonarworks

    Friend
    Joined:
    Sep 28, 2015
    Likes Received:
    943
    Trophy Points:
    93
    Home Page:
  3. peef

    peef Acquaintance

    Joined:
    Oct 5, 2015
    Likes Received:
    83
    Trophy Points:
    18
    You can build some of NP's designs with BJTs, if you really like. MOSFETs and BJTs and JFETs and tubes are usually interchangeable with a little creativity.

    A Zeus could be fun. If using BJTs in lieu of darlingtons, you probably want to use a CFP or a Darlington to keep the input impedance high. Since you won't need much gain, you can use some step-down on the output transformer and run the active devices at a lower current.
     
    Cspirou likes this.
  4. Grahad2

    Grahad2 Friend

    Friend
    Joined:
    Jan 26, 2017
    Likes Received:
    789
    Trophy Points:
    93
    Location:
    Singapore
  5. JeffYoung

    JeffYoung Almost "Made"

    Contributor
    Joined:
    Apr 11, 2017
    Likes Received:
    119
    Trophy Points:
    43
    Location:
    Ireland

Share This Page