22 Apr
2005
22 Apr
'05
9:09 p.m.
Tony Duell wrote:
The batteriers are long-since unobtainable (at least
not easily). I run it
from the mains. The LT is triival to get from my bench aupply. For HT,
I've made a little PSU from common components that gives about 85V (high
enough for the set to work well). It's just a 30V transformer feeding a
voltage doubler circuit. Much easier to get a 30V transformer than
something of a higher voltage now.
I must try the circuit that was in Elektor a couple of months back to get
90V from low-voltage batteries.
Also with the low cost of power fets a simple zener diode voltage
regulator is peanuts in cost to
do. The only catch is the case is HT in. With a simple one or two tube
set some 5 watt zener diodes
might work better.
-tony