300B single Amp Solo I

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Design Concept

 Tough and robust was the first virtue. All the major parts were arranged to be visible, especially the tubes were arranged in the center, making them feel the main character. In some ways, it may look like a jailbreak, but “the best protection” is the intended design concept.

Rectifying part

S-5AR4 5AR4
S-5AR4 / 5AR4

It is compatible with 5AR4, and the turn-on time is increased to 45sec to extend the life of the 300B tube.

INPUT & DRIVE concept map

300b single amp solo inputdrive

 We applied TR to the phase inversion stage and designed the gain of the TR to be less than 2 so that it depends entirely on the characteristic curve of the ultra-short tube. 

In addition to the feedback circuit for DC stability, it is possible to feel the characteristics of a pure triode without any NFB and the sound quality of a transformer (Rundal transform) alone. (No coupling capacitor)

Output portion

PDF FILE in preparation

By applying the current correction circuit to the conventional magnetic bias circuit, the initial setting value is kept constant until the life of the 300B is reached.


  • 8Ω Load MAX 12w (THD = 3% or less)
  • 4 In Put RCA only
  • LP In Put Sensitivity = 72dB based on 1Khz and MC cartridges only.
  • FM/CD/DAC In Put Sensitivity= -3dbm MAX
  • Balance / unbalance Head Phone Out Put
  • Ac In Put = 220v / 60Hz ± 10%
  • Size = (WHD) 430 x 225 x 275
  • Weight = 28Kg