I have a BTI LK-2000, which uses a 3-1000. I thought I might add a
string of forward biased diodes in the cathode circuit to set the idle
current. Looking at the schematic, I find only a 12 V coil overcurrent
relay shunted with a 10 ohm, 10 watt resistor in the cathode to set the
operating bias. There is also a 50K, 10W resistor to cut off the tube
when the amp is not keyed.
The HV power supply has been rebuilt, and now has much higher output
voltage than the factory supply. The manual specs idle current of
175-200 mA at 2600 V with the old PS. Power supply voltages are as
follows.
OLD: 3400 V, no load NEW: 3650 V, no load
3000 V, at idle, 180 mA 3500 V, at idle, 220 mA
2600 V, at 800 mA 3200 V, at 800 mA
Anyone out there with a set of 3-1000 specs/curves that can tell me if
my present idle current of 220 mA at 3500 V is OK, or do I need to set a
new bias point?
By the way, the schematics I have are dated 1969 and BTI stands for Brad
Thompson Industries for our younger amp reflector members.
73, Dennis-K5YA
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