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SPICE Modeling of Miniature Dual Triode Vacuum Tube for Audio Application
Author(s) -
Oshimo Shiori,
Takemoto Kanako,
Hamasaki Toshihiko
Publication year - 2018
Publication title -
electronics and communications in japan
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.131
H-Index - 13
eISSN - 1942-9541
pISSN - 1942-9533
DOI - 10.1002/ecj.12069
Subject(s) - triode , perveance , space charge , spice , voltage , vacuum tube , physics , modulation (music) , computational physics , electrical engineering , acoustics , electron , engineering , quantum mechanics , capacitor
SUMMARY In this paper, we describe novel high precision SPICE modeling for triode vacuum tube, which is attracting attention in electronic musical instruments continuously and recently in the field of audio systems. The advantage of proposed high‐precision modeling is that it is created considering the difference of space charge distribution originated from the difference of electrode distance between triode tube 12AX7 and 12AU7. It was found that the characteristic of the space charge change appears within the grid voltage range of minus 1 to plus 1 volt with respect to the grid current versus grid voltage I g ‐V g curve. In this range, thermal electrons are accelerated from the initial velocity condition of the Maxwell distribution. Based on this analysis, the modulation model formula of the perveance value G s , which is the key factor of the space charge, is obtained. Subsequently, we extended the model formula to the cathode current versus plate voltage I s ‐V p family curves with the grid voltage as a parameter in consideration of the perveance G s modulation effects. Finally, I g ‐V p family curve model equation is derived. Comparing the simulation results of the AC characteristics performed using the proposed model equation and the conventional SPICE model equation, the superiority of the new model equation was confirmed.