I build it, and it sounds amazing. PG and SG should be connected. It's the same Ground point. With two LME49710 it has zero noise at max volume with no signal. Thank you for schematic! UPD: I replaced 47uF caps to 100uF. Not sure, but feels like sounds better.

Cool little amp. good explanation Sir.

Just finished my version of this circuit last night. It works for sinewave on 30 Ohm load - now I have to hook up earphones and take a listen. Running on two 9v batteries with NE5532 front end. Thanks, John, for the simple circuit.

This is exactly what I was looking for and the exact amount of resistance for my headphones thank you so much

I would like to see your next video to this in which the amplifier in finalized on a perfboard and final amp is build.

I WISH I HAD YOUR KNOWLEDGE !

Hey John. I hope you read this comment in this 6-year-old post. I came across your channel recently and been enjoying watching your videos a lot. Thanks for sharing your knowledge. I'm interested in building this headphone amplifier to power my old Beyerdynamic DT331 (40 ohm, 86dB/mW) at no louder than 80dB (to not make my tinnitus worse lol). DC power would be from a 19V 1.5A SMPS adapter I have. Assuming DT331 dips to 20 ohms and its sensitivity measured at 1kHz (I couldn't find an impedance graph or detailed specs), I estimate I would need 7mA (both channels) or 28mA (for +6dB headroom at low frequencies). Biasing the transistors would require 4mA, and the NE5532 idle draw is 8mA. Thus my total estimated peak current requirement equals 40mA. I'm thinking of using a TLE2426 IC to split the rail. Would you agree with my current estimation and do you think TLE2426 would work in this case (or too close to its limit)? Thanks. Bill

If you find yourself needing better equipment to measure the limits of your amp, you did something right :)

What a fantastic work done. Like it

Would love to see a review of op amp driving 32 ohm headphones at low voltages (3 -9 volts) for portable use . Great project.

I made the "Power amp" version of this. With darlingtons. 8W 8Ohm, 6Amps, short circuit proof etc :D 10Hz-50 kHz linear. Simple but perfect circuit. Of course the soul of it the perfect IC. If you dont need darlingtons, BD-s are much better for High frequencies.

Hi John.. I am pleased to say and want to thank you for this video. I wanted to DIY a headphone amp and I have implemented your schematic and made a headphone amp with some modifications. Also made schematic and PCB design and the PCBs are being sent to me as I am writing this. The sound quality of this amp is astoundingly good. I would like to thank you and share with you my project. Please let me know how I can do so.

Thanks for the video and schematic! You didn’t use a heatsink on the video, is it even required for this build?

brilliant tech stuff

Would you be able to design one of these for two isolated stereo inputs to a single output? Would be *incredibly* useful for we nerdy gamers (eg; TV audio out from consoles and PC audio combined and amplified, to be fed into good high-impedance headphones)

Great as always! My favourite channel, I wish I had the means to try out what you create. Did you also try it without the feedback? Some say amps sound better without, this would be a great test for that.

70 ohms is low for a headphone I would have thought. Most headphone outputs would expect 600 ohms... unless im wrong. But the point is, in which case, its actually over loading

John, this is a winning amplifier design. Nice work. What's a good source for some genuine BD139 and BD140 transistors? What diodes did you use on this John? Thanks!

So great!!

Great video John. Im just starting out messing about with op amp circuits and was wondering why you used a 2.2uF cap on the input as this seems high to me due to it passing frequencies as low as 7Hz. (im sure you have a good reason for it). I have yet to build it but, it will the next one into my breadboard later this week and Im looking forward to trying to get it to work for my 250 ohm Cans. Cheers.

Great work, thanks!

What about OP50?. Nice video. Cheers from Indonesia

Steeleye Span. Knew there was something about you I liked... 😎

So you meant more current output. Oomph it to the headphone. 20 ohm output impedance would be luxurious on looking at your circuit though, you'll drive a speaker at 16 ohms to 1W no problem with that 😂

you can make a 10x amp and that way any distortion will be 10x , bringing you from 0,2% minimum detection to 0,02 witch is about as good as you really need , you probably know this . one good set of op amps will do that powered by batteries .

Great fun thanks for sharing

Hi John if I want to drive 32 ohm headphones (half impedance as yours) what change have to make to the circuit ? or use It just live the values as you stated un this video ? If you can take a minute to unswer this question I´ll order the parts to build one for myselt (probably put an output capacitor just in case one off the output transistors fail and pass DC to my headphones (cost me a little fortune), you know there are knock t off ransistors offs). Thanks in advance

Great video, John! Do you think this design would work as a booster amp for MP3 player/smartphone ->> auto AUX IN? I find player output direct to aux in requires full volume from player and the car audio system.

Did you think about thermal stability when driving lower impedance loads? You don't have thermal contact between the 1N4148's and output drivers as far as I can see. I guess those 10 ohm emitter resistors are going to prevent destructive currents, but I wonder if the bias current is prone to wander around without some stabilization?

You can make it class A type For 500mw headphone class A can work best

Hello! Very good video! I was looking for a headphone amplifier when I accidentally bought a behringer mx400, which is a mixer instead of a headphone amplifier, so it means four imputs instead of four outputs.. The look of both, this one and the ha400, is almost the same, I was wondering if I could turn it into a headphone amplifier easily, both has 4 channels with volume pots and the AC input is the same... Thanks!!! and just subscribed to your channel! :)

Just found ur u tube channel 2 days ago and im. Glad i did i love seeing this stuff done i just got a pionner 1021-k reciver and learned out after i bought it that they had a flaw in them from the factory for the dsp chip what happens is it will get hot then loose conection with the board and heating them up to reball them is only a temp fix mines working fine but i was wondering what u would do to fix that problem or is there anyway i could stop it before it happens to mine i was thinking of putting a heatsink on the chip with a fan to blow on it other thing i noticed is heatsink pionner put in there gets really hot when u use the reciver so i was thinking of putting a fan on it aswell hope to hear back from u john

Seems like a very simple but impressive design, I have a question though. When do you know when to use polarized (electrolytic) vs. non-polarized (film or poly) caps?

sir I listening many hadfone amp but 6283 chip sound awsome clean verry chip prize in india why this is produced clean sound

Dear john, I build this amp for someone about 2 years ago, he had hi end types of headphones, recently i dont know what went wrong in the circuitry, but my friend lost left side of his headphones. I need to request that it would be a good idea to hv a speaker protection based on upc1237h in this final diagram. Im not good at working with relays john. That's why im requesting.

Hey! Nice one there. I was just wondering if you could explain what are the characteristics of well designed PCBs as far as audio amplifiers are concerned. Thanks.

Can a 32 Ohms headphone be used on Front & Rear Line out sockets on Desktop computer without headphone amplifier?

very clean hp amp indeed.. i have a question, if i want it to be battery operated and compact, can i use a buck converter (probably 9v step up to 18v) and use a rail splitter capacitor? will it sound as clean as using 2 9v battery?

So I built this kind of headphone amp but its got bugs. I see how you put power to wrong pin, then I looked up internet data pin out to double check if I did that and I get a "wrong" pinout and go switch pins and ... well not good. LOL.

are those bd135 npn/pnp pair ? different transistors have different audio signatures heard, and bc548b sounds really weird and kinda sharp.

is there a way to determine what type of resistor do you have in stock (I mean metal oxide vs carbon) ? Any visuals ?

Can u review the pre built aliexpress headphone amplifier tda1308 and tpa6120 ?

Would you be able to substitute some JFET in without much modification? Working through the circuit on paper and I'm having some trouble

i can connect 1ohm resistor insted of 10 ohm

Hi John, I tried your circuit but I couldn't get it to work :o( The only way I could get it to work was to have the Opamp with its own local feedback then take the amplified signal into the push pull network. If I tried your way of including a global feedback, then the output was more of a square wave! Love to know how other people have got on with this circuit.

How would you add more bass to that circuit? Would it be adding higher capacitor to the input or output? Or changing the RF filter on the input ?

john I wish you build a circuit board and schematic to show us all how to build so we can download .im tierd of coking my brain with wifi headphones if you have the time it would be great I realy like clean sound like class a

run it on split rail +/- 8V from 18650 batteries. That would be plenty to blow your eardrums. +/- 4V would be plenty 😂

Why have you decided not to include the output transistors into feedback loop?

where i can get the final schematic of this test sir i want to create this one :D BR

I've watched many a amp video, and why pay hundreds of dollars when this 4 dollar works just fine.

How can I scale this for more voltage?

Can I use that schematic with 32 ohm / channel headphones?

Where I'm supposed to plug the ground of my headphones jack? On the 0v rail? Or the - 9? Because in reality the 0v rail is at 9v and the - 9v is at 0v...as the +9v is at +18v...i dont get it :( My transformer is +20v 0v -20v so if I take the ground of my headphones jack and connect it to the 0v rail, will I send 20v straight to my cellphone?

What transistors did you use?

Hello John. Can you give any tips on how to figure out bias resistor values. I'm building output stage on Darlington BJT's and this thing is not wanting to cooperate)

The schematic that you are showing does not match what is on the breadboard.. On the breadboard you have an op amp, audio driver, and output transistors'

Thumbs up from me also.

How do you get +9 and -9V without a power supply?

I made one amplifier using two bc547 for may headphone!

Hi Sir.Is this working in A -class?

sir explanation japanis audio ic like stk la tosiba

I created gerber file with circuteMaker workspace.circuitmaker.com/Projects/Details/Yuval-Abadi/headphone-amp

Do you have email?