PNP preamp

Lol i write a whole page only to fall asleep during it and delete accidentaly whole work ;(( buuu ......short version. Its combined amp a CE stage mixee with CB stage. To compensate non inverting properties of CB whose will decrase output instead of enchancing it a CB part of amp sees AC signal ground on oposite signal polaity han CE stage so it create mirror image whose became in phase witth rotated output of CE stage adding to him not substract. This give a somwewhat cascode amp in signle transistor version.

Hey man im just in high school :D explain it more basic. Will it do tge trick or do I need something better?

What's the application?

Low gain (3 times) high fidelity preamp stage for my 36W mosfet power amplifier. I really need this kind of preamp

I make one for u take a look at it . circuit called "preamp" for now without description cuz im short on time.

Ideally, you'll want the smoothest DC voltage possible, but a 7812 or 317 should do just fine. I mean, I'm going to go out on a limb and assume that you'll be stepping that 12V down from an higher DC source that is already pretty smooth and clean. Both amps look pretty comparable to me. Sec's will use less power overall to do the same thing, but it looks like both match your requirements.

A lm7812 has good ripple rejection if it's used properly nothing u have to worry about problem is another type fast fedback loop stabiliszers when used to extensively create ripples itself tend to fall in wild oscillations sometimes in radio frequency and occasionally transistors inside perform secondary breakdown whose always end up by cracking loud noise when case explodes performing beauty catastrophical failure. Sometimes when this happens theoretically in normal work and none potential fail cause was observed this frequently means that some nasty pole is somewhere close to feedback resistors or just at elemens connected right next to stab and drive it to deadly oscillations. when precise qnalog voltage references and stabilisers is made a "pole zero plot" is a must to eliminate or avoid potentially dangerous track lenghts component values or some part connections.

Well the lm7812 needs a few external components to make it stable and prevent self oscillations but a few capacitors i can handle thank for the preamp

Indeed. Any LMxx linear regulator will need a few external passive components. Usually a .33µF on the input, and a .1µF on the output. I hate to cross post, but it also looks like you should be just fine using that KC507 you've got.

Its not a problem I can get other transistors relatively easy but this is what I have in hand.

Yes an external small mkt caps are good way to protect against oscillations. Actually almost all linear regulators recomends to use such capsmat output or sometimes to maintain minimum load current lime in some lm317 . And attention should be pay to place this caps as close as possible to not miss any pole that can be left behind.

Yeah I know they should be placed really close to the Ic and if the IC is far away from the actual circuit its powering another cap close to the circuit may be needed

This amp must dsign someone who also take a different look o transistor itself. I heard about analysing and design when u loom on transistor like on opamp where base is inverting input, emmiter is noninverting and collector is output with those differences that base is mostly voltage controlled and emitter rathe current controlled. So not consider CE or CB but like in op amp CE is an inverting amp with second input grounded directly or by resistors to form some feedback and when u flip u have noninverting amp where base input is grounded and emmiter is equivaent of +input in op amp very intresting is looking on CC topology it's consider like merge of CE with CB.

Oh and there is fourth basic operating topology of trannie about whose no one even hisper in any book. I read and identify it from script dated for 1955 lol and describe trannie completely.

Are you refering to the common collector voltage amplifier you posted? I too find it weird that its not in any book.

No it's not this strange common colector i posted here recently.