LJ "MiniMax 7-5687" is the the most popular vacuum tube line pre amp, and the best-selling item within 10 years of the LJ Audio line products. Custom made only within 1-2 week. Budget range Rp3-4 million.  See the article on Alex's Blog, www.audiotronika.com. Old stuff: here.

• Model: M7-5687 #10 (June 2012).
• Design:
  
  • Circuit: improvement version of "the legendary" AudioNote M7.
  • Circuit topology: classic anode follower, single-ended pure class A.
  • Feedback: zero global.
  • HV supply: tube rectifier, C-L-C filter.
  • Filament supply: AC.
• Features/Optional:
  
  • Input: 1 pair RCA (optional: 2 pair RCA, select by toggle switch).
  • Output: 1 pair RCA (optional: 2 set output, 1 pair for stereo main amp, and for sub-woofer output).
  • Power switch: one shoot toggle switch (optional: 2-steps firing rotary-switch: off > on stand-by (mute) > on operate).
  • Muting: with or without output muting relay.
• Key parts/components:
  • Tubes:
    
    • 1x 5687 old stock  signal tube (optional: 7119/E182CC).
    • 1x 6X4 (EZ90) rectifier tube.
  • Resistor: Allen-Bradley (USA) old-carbon composite resistor, Vishay Dale (USA) metal film resistor.
  • Capacitors (upgradeable): Bennic FPP signal caps or Russian PIO (paper-in-oil) caps, Rubycon (Japan) PSU caps, Nichicon gold signal by-pass caps.
  • ALPS vol-pot (Japan).
  • LJ custom power trafo and PSU choke.
• Chassis: LJ wood chassis (vinyl, veneer, solid wood, or black piano).
• Construction: point to point wiring, real star ground, chassis/earth float to ground line.