Одноламповый 0-V-1 приемник на 7MHz.
I made 0-V-2 in my junior high school age about 30 years ago. The line up of them was 6AU6,6AV6,6AR5. In these days I discovered that some kind of tube can be used with only 12 volts on it's plate voltage. See fig.3! I measured the 12AU7 with 12 volts characteristics. With this voltage the maximum plate current become 300 micro Ampere. I made 0-V-1 re-generate receiver with this tube. I could hear the BBC and VOA with a dipole antenna. I could hear the SSB signal of amateur radio by changing the re-generate ratio by the re-generate switch.
Kazuhiro Sunamura, (JF1OZL)