Discrete audio amplifier project PT5 finish input stage

[@jimmydburrell]

Thanks for teaching me! I’m really liking all the explanation and “out loud thinking”. It really very helpful to me to hear this kind of talk. Thank you. Mean it.

[@reinermunch5159]

A nice project for the coming frosty season... I like the idea to have an amp knowing how all parts acts together

[@unforgiven818]

Great videos and extreamly well explained. Would be good to have a dedicated playlist for this series of vids, would make it easier to follow its progression. Keep up the good work.

[@myenjoyablehobbies]

Very well thought out video series, my hobby in electronics is transistor circuit design, that's why I'm enjoying this series, I'm learning a lot, thanks for the teaching.

[@1959Berre]

Doing great John. Can't wait to watch the rest of the project.

[@researchandbuild1751]

So it looks like the current mirror is basically a constant current source but mirrored on both sides. And current source in collector is high impedance, giving high gain

[@christophschuermann6512]

Great video as allways, thanks. Fore probing very small input levels i you can use a attenuator of 10 to 100 and conect the probe at the input at the voltage devider. The amplitude of the singal at the is then simple calculated by times 10, 20, 100 or whaterver you use.

[@dibyamartandasamanta583]

I am really enjoying this series. You Don't give heart. So john please give me a heart

[@JohnAudioTech]

There you go!

[@circuitmonkey6653]

@@JohnAudioTech That Sir, is awesome!

[@SuburbanDon]

This is a great series. I'm interested in a kit. Thanks.

[@mikevincent6332]

In a real circuit, you dont need anywhere near the high voltage swings (without clipping) from this stage because you will be driving the base of the voltage amplifier stage from this stage - but as I listen you just answered an earlier comment about high open loop gain needed for global feedback to work properly, thanks

[@rosspottage8996]

Interesting amplifier development, have you ever thought of investigating Bluetooth 4.2 & 5.0 technology with their new Aptx, Aptx-LL and HD features. There are many inexpensive products out there some are even integrated into the amplifier itself.

[@ckimsey77]

I know this is intended and designed for audio, and to not overbuild/spend components are chosen as such. Usually though things can go beyond its intended performance so my question is this...Not overdriving with power, but simply could this design template be used to amplify a much higher frequency sine wave? Not at the peak V you are after, but a lower V high frequency sine but able to drive moderately larger currents?? (current control is more of a target, though somewhat consistent V values are ideal as it will run electrchemical reactions. Is high freq a problem? Can these trans. switch fast enough, if not could a simple easy use of faster switching T's be an EZ tune; or is it way more complex? Im close to seeing the big picture w all this (much thanks to you and amazing series like this), but high freq still melts my mind on how to get it to do what i want. Just a simple sine wave of high f which i can vary to fine tune the needed "sweet spot" i need in the electrochemical electrodes as the resonate freq will greatly drive the rxn with no extra power (current) input as the E.Field harmonc oscillation will cleave bonds into free radicals for reaction without using power by direct reaction of getting e- from the current flow. I pray you respond with any input or advice that may help when you have time. The chemistry works, i just need the appropriate signal im on the verge of a wonderful discovery but on pause due to electronics above my understanding. Id pay for your time should u b able to help. thanksthanks

[@christheother9088]

Is some sort of spectrum analyzer absolutely necessary for this stuff? Are there computer based tools that would work in the audio range?

[@BlankBrain]

Discrete audio amplifier project PART 1 kzbin.info/www/bejne/Zp6Wi6ecbd6phbs (Introduction) PART 2 kzbin.info/www/bejne/qF7aZGpshJ6MkKc (Supply voltage, Transistor SOA) PART 3 kzbin.info/www/bejne/q2rSoWB5d9GbrZI (Input stage) PART 4 kzbin.info/www/bejne/bZCygqmjr7ppiZo (current mirror)

[@iceberg789]

thanks.

[@freshkryp69]

Is there a discrete opamp thats better than a burr brown opa4134? Looking to experiment with a dual mono block amp I have. Thx for any rec's..

[@rich1051414]

MC33171(single), MC33172(dual), MC33174(quad)

[@BlankBrain]

TI's latest high speed automotive op-amps: kzbin.info/www/bejne/l3LNdpiklsZ5o7c Automotive qualification tends toward more robust designs. I may try some as R-2R DAC buffers.

[@christophschuermann6512]

OPA627 or OPA827 from Ti if you stay with Fet-opamps.

[@rich1051414]

I specifically recommended a non-JFET amplifier as he wanted to experiment with different things, but yeah, those are also good op amps :) Just much of the same.

[@JohnAudioTech]

It is hard to beat the best op amp ICs with a discrete circuit. The matching and trimming in the monolithic IC design is tough to beat.

[@DIYBill]

John - what’s your background in electronics ? Keep up the good work

[@JohnAudioTech]

I have two years of school but mostly hobbyist.

[@rrangana11]

Hi John, You mentioned a book by Bob cordell ... Can you provide the ISBN number or the title of the Book? Thanks,

[@JohnAudioTech]

The old book is out of print and fetching ridiculous prices. The new book isn't out yet (no ISBN). Old book ISBN is 007164024X

[@Peltio]

Nice book, but that Cordell guy should GEOTA.

[@MarkTillotson]

Doug Self's "Audio Power Amplifier Design Handbook" is another very comprehensive work about audio amps. ISBN: 978-0-240-52162-6

[@JohnAudioTech]

I got Self's book on an inter-library loan a couple years ago. I like how he addresses the silly audio myths right out of the gate. He has a sense of humor.

[@charlesklein7232]

this has nothing to do with what your talking about which i dont understand however can you wire speakers in "parallel because i have found really nice speakers but they are only 1.5 inches so you need alot of them.

[@kresoptube]

What is pilot signal?

[@JohnAudioTech]

A 4.5KHz non harmonically related signal at 1% the amplitude of the 1Khz fundamental. It is used as a visual comparison to the amplitude of the distortion harmonics.

[@David-hy5iq]

@@JohnAudioTech How do you add it to the signal, just by using two different (low distortion) function generators in parallel?

[@stephanc7192]

Thank you Also wanted to know

[@bixy9347]

David Skärgård John has made a video explaining how to make it.

[@David-hy5iq]

@@bixy9347 I found that after I wrote the comment above. Much more simple than I imagined! :) kzbin.info/www/bejne/mYOUha1umbZkhKc

[@BuzZ.]

Nice