Ed Boutilier on X: "model #813 vacuum tube originally designed by RCA in 1937. I built my first #HamRadio amplifier using 3 when I was 16 or 17 years old. When I
single-813 crystal oscillator transmitter under Repository-circuits -54291- : Next.gr
RH Amplifiers: RH813 – The Flagship Project
813 / GM70 amplifier with Bartolucci transformers
813 Vacuum Tube at Rs 5000 in New Delhi | ID: 6356776755