Bias 2879 observations

More power without the bias circuit installed

[@Mr.Amplifier.]

The BIAS has nothing to do with your RF power, the classification of an amplifier to be use depending on a different mode of communication mainly on SSB, you have to analyze the 2sc2879 on the oscilloscope where the transistor will not saturate "the sweet spot for the 2879." is different than the Toshiba, most I seeing are different. once you see the clean spot on the oscilloscope move on the board and do calculations to obtain the current desire. those two bias circuits you mention they become unstable depending on the temperature of the transistor and heatsink. if you really want to understand bias you must understand the important of electrodes, ions acceleration DC and AC noise. you will find this on the oscilloscope and audio quality will be notable onSSB only. the class B as you mention with .300+mA once the 10øhm resistor gets hot the resistor is losing its value and the current will increase taking the transistor to a class AB. However this will be dangers depending on the operator of being aware of the amp temperature, once the transistor gets to the point of saturation for a longer period of time, it will short out... 73.

[@electromechanicalstuff2602]

As far as power I'm saying biasing makes it more linear. So the power will come up on less watts at certain points. As far as power also. What I'm saying is a straight class c box without the circuit installed will make more power due to the direct connection to ground on the input transformer vs one with the circuit installed and turned off because the path to ground has to go through resistors and a diode. Plus when I'm talking about the current draw I understand it's becoming less efficient at a higher class. Thus is pulling more current. What I'm saying is with the original biasing circuit that came with the 8 pill Fatboy was a voltage regulated thing that did absolutely nothing as far as actually adding bias. I could tell because the amp never drew any more current this showing me it was not becoming less efficient. There is a conversation to be had about the decrease in spurious emissions when an amp is biased vs class C. As far as an o-scope I have one and am waiting on my sample plug so I can take an attenuated signal into it. So your saying these types of circuits become unstable how? What is the better circuit? These do have a bit of temperature compensation with the diodes sitting on the transistors. Lastly like I said it seams like the builders are just installing bias as inherited knowledge without really fully understanding what exactly is needed. Nobody can tell me what to shoot for as a rule of thumb for ab but everyone says 300ma for class b. I've gotten these things pretty hot while measuring bias current and it doesn't seem to really change much at all. 73 586 on the side Edit The 10 ohm when it gets hot the resistance will increase and thus decrease the voltage and current going to the bias. So it shouldn't go from B to AB if anything it should go from B and head further towards C if I'm not mistaken.