[Amps] Mangian wire

[MIKE DURKIN]

Ok .. do you really need the Mangeian Wire from the B- of the Filter board to the shunted amp meter?? I have my amp up and running with a GS-35b now and im sure that my bias isnt working right .... mabey it is ... but as it sits now .. i should have 30V bias keyed and im showing 60ma idle ... now this is why i think i still have a problem with metering - when driving with 30W im getting an output of 600W (carrier/cw -what ever) and the uA meter is showing only about 120 mili-amps of plate current. 

Second question is do you need plate voltage on the plate to complete the bias voltages (im talking through the tube) to the heater?? My DC at the heater is 120VDC cutoff and 4V DC key'd state (no drive). My Bias supply is not sagging and the collector of the pass transistor is tied to the center tap of the heater transformer ...... Please leave out comments about using a center taped heater transformer and the differences of using a bifilar wound rod for RF blocking - its simply what i have and plan on using for now.

If your wondering what amp again its a Yokagawa P93 blah blah blah.... i have posted the schematic (a scan of it- and a poor one at that) . Im thinking that the Bias supply needs to supply voltage at the collector via a blocking diode and say a 1K 5W resistor so that when the emitter is pulled to ground the Zeners are reversed by the Bias supply and not the tube leakage ..... at the current configuration im thinking that the 30V zener that i used to replace the pair of 4.1V zeners will never be properly reversed for the wanted 30VDC Bias ....

Mike
KC7NOA
 		 	   		  
_________________________________________________________________
Hotmail: Trusted email with powerful SPAM protection.
http://clk.atdmt.com/GBL/go/201469227/direct/01/