i have built a set of power for 81 eight years ago and 81 is my first rig.
1. for the transmitter, the trnsformer should be very large, 300va or larger is recommended or the sound will be chirp.never use a transformer less than 150va.
2. 6.3v should be larger than 2a, and the ripple should be low.
3. 1.2 or 1.5v is the most critical,because the filaments are directly-hated cathods, if not well designed very severer noise will exist. you can use a battery to get good performance.
sorry i am suing an english version windows and can not input chinese.
you can email me via
ba5bm@163.com.