TTH, as i said i am willing to learn, thanks for the enlightening post......what gets my goat is when someone critizes my post when it is clear he has no clue....as far as dc stability is concerned, the emitter resistors of Q1 and Q2 are supposed to provide dc compensation with temperature such that any tendency of the the collector current to rise with temperature results in higher voltage at the emitter resistors so that Vbe tends to get lowered and thus checking the rise of collector current, yes i have overlooked the effect of the 2.2k as i was thinking that the emitter resistors should have been sufficient.....the best way to find out is to breadboard the circuit...perhaps skyjam can provide us with operating points of the trannies.....@skyjam, can you post the voltage readings for base, colletor and emitters of each trannies in the preamp section?my rule of thumb looking at transistor circuits is that hFE's of modern small signal transistors are often quite high so that they can often be ignored....analysis proceeds from here...the goal of design is to come up with circuits that that are independent of hFE basically for as long as hFE is >>10...the universal equation for gain has always been gm x Rl, transconductance x load resistance and is applicable to all devices be they tubes, or transistors....this preamp stage has very high open loop gain, while closed loop gain is low....
TTH, you know this is a good mental exercise for me as i am forced to re-learn, +1 for you....
skyjam is avery prolific diy'er, kaya nga todo supporta ako sa kanya....idol ko yan....
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Topic: 60 Watts amplifier (Read 4056 times)
