Setting up a "single supply" audio amplifier

[@migalito1955]

Thanks John. I build stringed instruments in my retirement which led to simple combined pre-amp/power-amp practice amps along with pickups and filters to take out unwanted high frequencies that make an instrument sound harsh. I use op-amps for the preamp and needed an effective but relatively simple way to generate the dual power supply for the op-amp and your video was a great source for methods.

[@low-key-gamer6117]

Didn't know Peter Parker had a youtube channel where he teach electronics

[@steveone]

Another classic JAT . Thanks John .

[@KarlAdamsAudio]

Excellent video, much appreciated. One small wrinkle to your analysis of the low-end rolloff due to the output coupling capacitor is that the actual impedance of a loudspeaker at 40Hz may well be considerably higher than the nominal value - near the resonant frequency of the driver the impedance peaks quite considerably.

[@JohnAudioTech]

That is true. Also, ported speakers will have a dip in impedance at the tuned frequency.

[@jainvibhore1997]

Thanks!! That was quite quick and neat! I accept your challenge and will soon make an amplifier with a chip amp.

[@PeteVanDemark]

And... touch the input to the output cap... Oscillator! Ahahahaha! You have a great electronics sense of humor, John!

[@MultiCraftTube]

Nice circuit. Tried it, works :D Thank you for nice explanaition.

[@21thTek]

Excelent as always !! ⭐⭐⭐⭐⭐

[@tectalabyss]

Very well explained Thank you John.

[@Enigma758]

Assuming the input stage has a bipolar PS, what is the relationship (if any) between the bipolar PS ground and the unipolar PS ground (0v)? Must they be common? Or does the coupling capacitor (input side) eliminate the need for a common ground? Sorry, I know this is a basic question, but I want to make sure i fully understand the fundamentals.

[@TheTrueVoiceOfReason]

How about a split supply using two equal value capacitors in series between supply + and supply ground, with circuit ground referenced between the two caps? I've seen that used before, also.

[@ats89117]

The discussion at 16:00 isn't right unless your speaker is a purely capacitive load at 40 Hz. If that were the case, the impedances would just add together as you've assumed, but this wouldn't be a good assumption for a voice coil type speaker. On the other hand, if the impedance of the speaker is a purely resistive load at 40 Hz, the impedances will add as orthogonal vectors. And if the impedance of the speaker at 40 Hz was purely inductive, the impedance seen by the opamp would actually decrease...

[@TechTins_Projects]

the random bug was funny. Nice touch.

[@MichaelBeeny]

I thought it was on my monitor until I found I could not remove it!

[@mrjohhhnnnyyy5797]

Great vid. And what about a bridges? They don't require cap to AC couple the output.

[@JN7583-k7z]

Hi. What's the purpose of the 0.22uF and 2.2R to ground at the output?

[@JohnAudioTech]

This helps with stability of the circuit. I might oscillate without it.

[@joohop]

Thanks your a clever fella ! Do you ever mess about with Valves / Tubes ?

[@lokonleged7278]

Helo sir, i want to ask, i make lm1875 single supply, i follow the datasheet , but the sound not so good like dual supply, i mean like deficiency supply

[@Omarbg95]

what are exactly the values for the capacitors? I mean like what are they uF, pF, mF, nF, etc.

[@johnyang799]

uf

[@iblesbosuok]

Unit-value of capacitor is Farad. pico: 1pF=1/1,000,000,000,000 Farad =0.000000000001Farad nano: 1nF=1/1,000,000,000 Farad =0.000000001Farad =1,000pF micro: 1uF=1/1,000,000 Farad =0.000001Farad =1,000nF milli: 1mF=1/1,000 Farad =0.001Farad =1,000uF Cheers from Indonesia

[@chikku168]

I had already made a stereo amplifier using 2 tda 2050 and used it in my car . every time that I turned on the amp it always made a popping sound i thought it was the low voltage now you have mentioned the reason for it I think I should change the amp with some thing that runs with single supply can you suggest me an ic which is best in output power at the 12 volt single supply

[@kayquexavier]

but what to do if the only thing i have is a computer power supply? (only one).

[@tonitrum4219]

Are all the caps in micro farad?

[@TheBaconWizard]

yes.

[@BernatSCasamitjana]

the values of the capacitors are in F?

[@yeeboi5545]

looks like all the unlabelled ones are in μF

[@iblesbosuok]

Single supply amplifiers frequently confusing me determine where right point to separate signal-ground to power-ground. Cheers from Indonesia

[@johnyang799]

Then don't think about grounds. Think about one ground and a bias point.

[@rahulkumar-qu2xo]

sir---i made it work fine--clear sound--40 v single---getting only 0.3 a ---12 watt----only change i made is using 22 kohm and 3.6 ohm in place of 2.2 ohm, using fake ic but at 40 v it should give 22 w acc to datasheet---usually fake ic gives 4 watt lesser then i should get atleat 18-19 w not getting---------why ?

[@kevinlivingston9563]

Hey you sure have been cranking out videos lately. How about a single supply crossover circuit??

[@JohnAudioTech]

Not sure I follow you. Do you mean a single supply active filter?

[@kevinlivingston9563]

Yes sir

[@kevinlivingston9563]

With a ne5532 possibly?

[@jainvibhore1997]

Here is the breadboard version with some minor tweaks. kzbin.info/www/bejne/pHzNmo2CatxrjtE Thanks a lot again!!