Transformers
13W tube single-ended output transformer can be used 6P3P EL34 FU50 FU7 KT88 etc.
Silicon steel sheet 76*40
Primary impedance 3.5K B-G-P (G super linear)
Secondary impedance 0-4-8
DC resistance 248
Inductance L>=28H
Frequency response: 20hz-25khz
Pure oxygen-free copper wire winding 4+3 winding method layered and segmented