DIY stereo preamplifier design & build

[@MichaelBeeny]

Nice job John. I love that chip, used it over many years. Never had one fail, very low distortion and noise. Has really stood the test of time.

[@Egam]

You should do a video on how you make those boxes, it looks great!

[@alejandrofrancis5530]

I guess Im asking randomly but does someone know a way to log back into an Instagram account? I was dumb forgot my login password. I would love any tricks you can give me!

[@jaxxdamien7452]

@Alejandro Francis instablaster :)

[@alejandrofrancis5530]

@Jaxx Damien Thanks for your reply. I got to the site on google and I'm trying it out now. Seems to take quite some time so I will reply here later when my account password hopefully is recovered.

[@alejandrofrancis5530]

@Jaxx Damien DAMN IT ACTUALLY WORKED! Just hacked my IG account details after ~ 45 mins by using the site. Just had to pay 15$ but definitely worth it =) Thank you so much you saved my account !

[@jaxxdamien7452]

@Alejandro Francis You are welcome xD

[@davidjones9730]

Another excellent video, I will try this for the bench. Really enjoying your whole series of videos, so clear and informative. Thanks.

[@KarlAdamsAudio]

Nice build, looks like it'll come in very handy. The 5532 is a totally appropriate choice for this application, I think - it's worth remembering that when they came out back in the late 1970s those things were the cat's meow, and very expensive too.

[@darinbrunet4600]

Still a great chip for lots of circuits. I use the dual version with one side as DC servo to drive a buf634 or diamond buffer nested in the feedback loop. Very good performer.

[@SebastianScholle]

I've foreseen this one long time coming. I'm on the same project path. Keep up the excellent work!

[@jonjones112]

John, you are a great asset. I have looked to you several times for ideas, as have many other people, and I will keep going to you as my source. Thank you.

[@JohnAudioTech]

Thanks for the kind comment!

[@cafe80s]

This looks like a great project! And I really like the enclosure too!

[@kgarvey2147]

Great project. Two things can really help some of us newbies. A BOM list; and another video on how to create a breadboard version of a simple schematic. Know this is entry level stuff, but it can really help us see your methods.

[@CoolDudeClem]

Nice preamp, this reminds me I need to get on with my balanced mic preamp build, just waiting for some parts to arrive.

[@JohnAudioTech]

I look forward to your project. I watch all your vids!

[@BogdanSerban]

I've built myself a crossover system using NE5532, really nice op-amps. I suggest using plastic caps instead of ceramic or tantalum, you'll notice a great improvement in audio quality.

[@JohnAudioTech]

Ceramic is ideal for supply decoupling because of low ESR and inductance. The designers who develop these ICs recommend their use. However, I would not use them in the signal path due to non linearity over their voltage range.

[@phasehalide]

Thank you very much for your schematic and video. You helped me understand some things about setting Op-amp gain better. I had tried making a preamp like this about 25 years ago when i was a novice constantly burning stuff up. Made and learned so incredibly much since those days. Added some more components for my application and put it together on a protoboard like you. Used a simple JRC 4558D to test with then switched to what i really wanted the AD822A and saw the difference in the op amp's detail and dynamic fidelity in a minute just by swapping out the first IC. Previously used the LM4562 a lot and love it too. Working on the first go with no problems on first power on, very happy i revisited this one with you. Now its time to draw a few in Eagle alter/add some things more photo transfer and etched out onto proper fiberglass boards. I am however replacing the classic badly made embedded pre amp's in car and home amplifiers and needed something just for gain control cause i always control everything else with a DSP.

[@gandsnut]

Love the shift from Beethoven to Funk.

[@wcovey9405]

well built and well performed. For fun, and interest, I think you might like to look in the LM4562 chip.

[@JohnAudioTech]

I have some 4562 op amps. They are fine performers. I think it uses a bit higher idle current than the 5532.

[@muimasmacho]

Half the fun of these projects is to indulge yourself a bit. Anything worth building, is worth over-building. 😶 In my recent preamp build, i series connected the batts and then bootstrapped and buffered the vref (TLE2426) so the output swing will remain perfectly balanced regardless of battery charge imbalace or deteriation. This way i can also use 1, 2, 3, or 4 x 9V batteries - simply - depending upon output requirements. 😀 Then i added an LM3914 to be able to monitor the condition of battery/batteries... momentarily activated. i used an OPA2132 FET input opamp _(NE5532 is BJT)_ due to its very high impedence input and low offset, which practically removes the need for an input buffer with delicate input sources. As a multipurpose lab tool, you can't always count on a stiff input source. (Guitar pickups, or piezos for instance.) Ya never know! This allows for the use of 500k, or even 1M+ input attenuators, though 10k offers less (Johnson) noise and works well in those cases where you have a stiff input source. Lastly, i added dual LED display VU meters (segued) to monitor the outputs using two LM3915's just for quick assessment purposes should things happen to get goofy. This provides easy visual verification that serves to speed up the process of elimination, without the need of handheld meters and or scopes. Yes... All these things add to the complexity and cost... *_but we have the technology!!!_* ... and we're only talking about maybe a $20 increase... which is a hell of a lot cheaper than any one of my other LAB TOOLS AND EQUIPMENT. When you stop and think, we can get a lot of bang for the buck these days... and if you agonize over spending a $1 or $5 for a practical feature, you probably can't afford this hobby... or any other for that matter. For simplicity sake, i built each feature as a seperate module... and can easily harvest them for other projects, or should i decide to reconfigure later. It is a build i am very proud of, even though it wasn't much of a challenge. Being unity gain stable, it works well as a buffer too. It is far more useful than i ever imagined it would be. But simplicity works too. Cheers.

[@raymondheath7668]

You inspired me to build a preamp for my bench. I had a NAC42.5 kit (all transistor) on the shelf and the case of a 8A switcher power supply I used for a power supply project. It has a dual volume control and takes 28VAC input which it splits and regulates on board. I used two stereo 3.5mm jacks since most of my stuff is 3.5mm or I can make an adapter for use

[@sayantanmaiti2513]

That's a very nice preamp sir...learnt a lot of theory...your case looks very clean and beautiful...I'll also try your design

[@michaelbauers8800]

So much cheaper than a Yamaha pre amplifier, and still pretty nice looking for DIY.

[@dannyhoang3192]

I will build the same with your design as I saw you presented that work fine. Thank you so much 👍

[@maclayyc]

5532 has less internal compensation and very high slew rate, so it's critical so have a high frequency feedback path (capacitor in the feedback) to keep it stable

[@snaprollinpitts]

when you said the gain was 11, you should've used a British accent for the Spinal Tap guys out there.

[@NickP333]

snaprollinpitts LOL! Perfect! And a song in the key of D minor, the saddest of all keys...

[@snaprollinpitts]

@@NickP333 thanks Nick!!!

[@g1fsh]

nice project John im the same as u i find it hard to box projects up and make them look good. yours looked good tho well done.

[@jacobstahl7467]

i'm impressed with your videos. Keep it up John

[@techtruth9077]

The 5532 and 5534 is still used in a large amount of HIFI and recording studio equipment.

[@darinbrunet4600]

Tech Truth They are still quite good performers and sources everywhere. Good choice.

[@manFromPeterborough]

I have the TC-780 line level booster with the same chip inside, great for ext phono stage going to a mini amp with poor gain (Dynavox CS-PA1) and for records with low levels, eg 20 track LPs

[@HillsWorkbench]

Excellent! I've been contemplating doing something like this too, so I can use my netbook with a function generator program.

[@JohnAudioTech]

Good idea. It would also be a safety buffer between the output of the netbook. I ruined a nice headphone stereo player once when its output contacted a supply rail of an amp I was working on. Have you found a good function generator app?

[@HillsWorkbench]

Just the Marchand Function Generator Lite, which I think you've seen. Really need one with a sweep function, though I guess one could use it's noise functions instead to evaluate response. Haven't searched in awhile There's a whole new generation of less expensive synthesized FGs out there now. Probably going to get the little German kit with the housing though at that point it's about double similar Chinese ones. On my test bench, test equipment NEEDS to be in a housing! But it looks to be more than a trivial build and I have too many other projects demanding attention.

[@manFromPeterborough]

@@JohnAudioTech I've had a valve radio-gram send 200v into the O/P of my CD player only zapping a C536 transistor, the reason was the stop on the selector knob was broken

[@ferfromla]

Thank you for this. Very informative, you are an excellent teacher.

[@darinbrunet4600]

John I would add a 10uF tantalum bypass cap with that .1uF ceramic you're using. You might better perf. Power supply bypassing is very important.

[@amirshokati6377]

Hi John, very nice job and thanks for sharing it with us. I wonder what is your player output voltage range? I saw you use the same for pre amps and some small power amps. I understand you designed the gain for this preamp 11 with using 9V battery, why clipping voltage is around 4.45V rms which is 6.3v p-p?

[@RexxSchneider]

I think you'll find 4.45Vrms is about 12.6Vp-p (for a sine wave the conversion factor is 2√2). He did say the 9V batteries were tired, so that may account for some loss of swing, and finally the NE5532 won't swing rail-to-rail. In fact, they are specified as only 26Vp-p with a 30V supply into a 600R load, so I'm not surprised he was getting just 12.5Vp-p in the circumstances. Even with a solid power supply, I wouldn't count on the NE5532 to get closer than a couple of volts to either rail.

[@carlfranz6805]

Have you looked at Elliot Sound Products (ESP)? His project page has a much improved attenuator using a linear taper pot. Also a relatively cheap circuit board similar to your circuit. Also, I'd find it interesting to have your review on some of his stuff. I'd paste in his web page, but my phone is notoriously, ridiculously bad at cut and paste. 😐

[@michaelbauers8800]

ESP has been my mentor for a long time. Not personally, but when I got tired of all the subjective golden eared snake oil nonsense in the audio community, he was one person who I found could explain the engineering side of things. I am a convert to "If it can't be measured then it can't be proved, and is therefore simply opinion". This has saved me money.

[@kevinlivingston9563]

Nice little build. John how can we support your channel bro?

[@JohnAudioTech]

Best thing viewers can do is let the commercials play. It helps content providers earn more from the adds.

[@TBL_stevennelson]

I don't have then I pay KZbin so I don't see them. Does this effect you.

[@scottyluxton]

Hi John, love your channel mate I've learned so much from you! - just wondering why the 20k 'reference and bias' resistors are needed in my head they seem to do nothing but bleed some of the input signal to ground via voltage divider with the opamp input impedance? and setup a HPF on the input?

[@terencekaye9948]

Hi John I realize this is going back a ways , I'm wondering if the LED's you used are still avaiiable ? Thank you for the great video 🙂

[@MarcelOoms]

very nice! Have recently been using the LME49720 instead of the 5532, also cheap and somewhat better specs and sounding cleaner . They say it's the same internally as an LM4562. But that would be overkill I guess. Love your video's.

[@JohnAudioTech]

Hi Marcel, The story I heard was that National started the LME naming for some of the high performance op amps so they brought the 4562 under it with a new name. The 4562 already was popular so they kept that part number as well. Don't know if it is a true story. I have a few 4562 chips around. It needs a little more current so I went with the 5532 in this project.

[@michaelbauers8800]

I admit to lacking knowledge, but I thought op amps were differential amplifiers. What benefit does it provide to feedback output back to inverted input, for this application?

[@micomrkaic]

Hi John, a fantastic video. Could you please tell us where you got the enclosure? Many thanks, MM

[@amirshokati6377]

do you suggest using 10 ohm resistance between input ground and supply ground for isolation or it does not need that?

[@Helectronics]

Really good video, well explained. I have a question, why haven't you used higher input biasing resistor values (ex. 47k, 100k)?

[@JohnAudioTech]

Higher resistance = more noise.

[@Helectronics]

@@JohnAudioTech Thank you!

[@stevepearson8791]

Great video i learnt alot even though im a newbie how did you cut the acrylic

[@TBL_stevennelson]

I thought you did a great job cutting it the ends look perfect. Don't know how you did it

[@MrDunk66]

Would iPhones work adequately as signal sources to replace your Walkman in the type of testing that you do?

[@gino3286]

Hi thank you very much for your great video At 18:30 do you use the scope as spectrum analyzer ? how is it possible ? i am quite ignorant but i thought that a scope does not make measurements in the frequency domain and a proper spectrum analyzer is needed

[@JohnAudioTech]

Hi. Most modern digital scopes have an FFT mode (basic spectrum analyzer).

[@gino3286]

@@JohnAudioTech hi thank you so much for your kind and very valuable reply I would like to start measuring some distortion spectrum on line preamps only line preamps are my obsession The one you made is amazing for performance indeed Is your scope the best option in its price range ? audio analyzers start from about 600$

[@JohnAudioTech]

@@gino3286 Unfortunately the bit depth of digital oscilloscopes is not enough for measuring low distortion levels. .2 to .4% for 8 bit scopes, for example. You can use your computer's sound input to do a little better (use ARTA software and input attenuator). I recently bought the Quantasylum QA403 as it can go below -100dB on most measurements.

[@gino3286]

@@JohnAudioTech hi thank you so much for your kindness I see now that you have a video on QA403 unit Seen it and it is excellent indeed I could make me a gift for Christmas My need is just to get THD+noise of signal up to 3Vrms (the output of a preamp) I know Arta I know nothing about input attenuators Where i can find one ?

[@JohnAudioTech]

@@gino3286 An attenuator can be just a couple resistors to reduce the input to the PC's audio input so that you don't exceed its limits with the signal. Search for voltage divider circuit for more info. You can also use a good quality potentiometer.

[@karlh.peterson8134]

Nice video, I like it. Some notes if you will. Why did you go with 20k range on the feedback path? I thought your goal was to have very good noise performance and choosing a lower value range would make a measurable difference. I suggest you try min. 470uF as coupling caps, should make a difference in the low end. Might make a good experiment to try this out. And finally, PSU decoupling usually specifies 10uF and .1uF in parallel, why omit this if you are building a general purpose preamp? Again, thanks for the video.

[@JohnAudioTech]

I was hoping the lower noise metal film resistors would be enough. Connected to my power amp with both volume controls fully open it is still very quiet given the combined gain of the amps. The cutoff with the 2.2uf input cap and 20K input resistance is 3.6Hz and down only a small fraction of a decibel at 20Hz. I'm not too concerned with frequencies below 20Hz with this amp. I had power amps oscillate with capacitive loads with .1uf film supply decoupling only, but stable with .22. If I find I'm having issues without the lytics, I can add them but I'm expecting I'll be fine without. You have good questions. This amp is not meant to be technically perfect in all ways, but is very good for what it is. I was expecting people to call me out for using a plastic box and minimal shielding around the amp.

[@charlesklein7232]

i use a microphone that is plugged into a desktop computer in the microphone plug on the back of the motherboard and i use audacity in ubuntu 16.04. i can here the microphone but it is not loud enough. their is a thing called "48V Phantom Power Supply" but this is for Laptop which does not give the microphone its full 5 watt power. on my desktop it has that and so i was told that it would not allow me to increase volume. but could i use a "PRE-AMP" before i plug into the computer to increase its volume. or basically how do i increase volume.

[@anti_globalista]

I've read somewhere that putting potentiometer before amplification is a bad idea.

[@RexxSchneider]

It all depends. If you have only a very small signal, you want to amplify it before you start to attenuate it with a pot in order to minimise the noise. However, if you already have a line-level signal and want to boost it somewhat, then putting the pot before the boost makes sense, otherwise you run into problems with clipping.

[@andreacorinaldesi581]

Great video John! Can someone tell me why the non-inverting input is grounded through a 20kohm resistor? what's the resistor for?

[@JohnAudioTech]

It biases the input stage. It should roughly match the resistance used on the inverting side.

[@SimpleEnough2k9]

Hi John, there are some NE5532 based preamps available as kits on eBay for example, would you recommend them ? I recently looked at the one that have bass, mid and treble adjustable along with the volume. They look ok to me but I just wanted to have your opinion / advice. Thanks.

[@JohnAudioTech]

I have not tested them yet. I usually find issues with their design, so it is buyer beware.

[@gandsnut]

Habit forced me to look at your schemat with L=in, R=out. THEN, wait, nope. Look again. R=in, L=out. Keeps your viewers on their toes. I'm guessing this opamp can handle shorts on the output; thus the absence of coupling on the output? Anyway, being socketed, you can blow IC's left and right and just pop a new one in. :)

[@RexxSchneider]

The datasheet says unlimited duration for an output short-circuit, but then warns not to exceed maximum dissipation, which is maybe about 1.2W or so, depending on ambient temperature. The output short circuit current is given as 38mA typical, 60mA max. You'll typically be fine with ±15V supply,

[@Bisdako2013]

Hi John, i made this preamp using TL072 & add a coupling caps at the output. it's working but noisy. this preamp ckt. should use a regulated power supply?

[@Bisdako2013]

or shall i use lower resistance input? let say 5k to 10k potentiometer. currently am using 50k. note: No added 100 ohm output series resistors.

[@JohnAudioTech]

@@Bisdako2013 What kind of noise? hiss or buzz. The TL072 is a bit noisy for audio. Buzz is a shielding issue.

[@Bisdako2013]

@@JohnAudioTech actually am using 22k resistors as the only I have. Let me change it first and comeback to you.

[@Bisdako2013]

@@JohnAudioTech I didn't change the feedback resistor value, instead I changed the input resistors to a little bit higher so that the gain is lower. Previously, I used a lower value input resistors (1.1k) resulting to high gain of 20 but noisy. Thank you John, I learn a lot from your videos.

[@joohop]

Nice work bud , how much would you charge for the pre - built board + instructions ? Stay safe

[@TBL_stevennelson]

I could use a parts list, I really want to build this. I'm so close to having all the parts

[@adaml52]

Hi John, I realise this video is quite old. I've just found your channel, liked and subscribed. I would like to build this preamp for my self, as I'm a novice to electronics. Can I use a 2.2uf polarised electrolytic capacitors on the input ? If so does it matter which way around they go ? Thanks Regards Adam, Yorkshire, UK

[@JohnAudioTech]

Yes you could but for a quality pre amp I would recommend you to use film capacitors instead.

[@adaml52]

@@JohnAudioTech Thank you John, I've just some film capacitor's today. I've made a home made printed circuit board and included a Dual gang 10K log potentiometer on the board. Also put two resistors on the outputs and jumper for combining in to a mono signal. I used you schematic values. Great videos, again thank you very much for the information 😀😀 Also found you video on star grounding and selecting the input capacitor. ATB Adam

[@facundonu]

great vídeo and channel

[@judges69]

Nice, easy to build little mini me.

[@correia707]

Hello John. Nice video!!. I want to know your opinion on opamps, which is best: N5532, BBE XR1075 or LM1036. Regards

[@JohnAudioTech]

NE5532 is great for its low cost. LM4562 and a host of others are high performance.

[@ronchinoy]

Input caps 2.2 what unit uF or Nf or Pf.

[@barbasbandas6665]

How did you build the poweramp to drive the speakers? or did you just connected the outputs of the opamps to the speakers(I gess that would not work)? Is that acomplished by some type of transistor amp? I am kind of confused. Thanks a lot for your videos!

[@JohnAudioTech]

The pre amp is driving a power amp to drive the speakers. The preamp doesn't have the current to drive speakers directly.

[@barbasbandas6665]

JohnAudioTech so the preamp only amplifies voltage while the poweramp provides the necessary current? So a transistor power amp is the better?

[@JohnAudioTech]

Yes, the preamp raises the voltage and the poweramp the current. Technically the power amp raises voltages as well so it is high enough to get the current through the load impedance (speaker) you need for the power desired.

[@barbasbandas6665]

JohnAudioTech Thank you so much! I really like your videos. Keep the good work!!

[@onlyfacts4me]

Question... What kind of rotary switch would be needed to switch audio input sources from a bluetooth reciever board and a pair of RCA audio jacks?? ... They would both be connected to the same amplifier. I'm clueless. Thanks in advance to anyone who can answer this.

[@JohnAudioTech]

To switch two stereo sources into one amplifier, look for what is called a double pole double throw (DPDT) rotary switch.

[@aleaatz]

Very Good !!

[@chulbulebachpankedin8012]

Good job

[@snaprollinpitts]

nice build!!! where did you get the box?

[@JohnAudioTech]

I made the box out of acrylic.

[@manFromPeterborough]

@@JohnAudioTech How much the project cost ? The TC-780 set me back AU$80

[@dantheman1998]

If your decoupling the power supply with capacitors..bit don't capacitors block DC voltage? I'm an electronics noob

[@michaelbauers8800]

I probably should not try to answer this, given my lack of electronics knowledge. But I can try. His design has .1 (pf?) caps between the positive supply to the op amp and ground ( same with negative supply.) This would not block the DC to the op amp. But could "shunt" some unwanted transients, or what you want to call them, to ground. It serves to clean up the voltage signal ( less ripple in the voltage.) See this article - www.seattlerobotics.org/encoder/199706/basics.html

[@H4zuZazu]

What for a Potentiometer type you used? Logarithmic or Linear?

[@JohnAudioTech]

log

[@H4zuZazu]

Thank you very much.

[@niklaswinter5160]

hey John, nice Video ^^ I built this little pre-amp and it works great. But only with certain OpAmps... The lm833 and Kia4558 works great, but the 'high performance audio' OpAmp c4570c causes a lot of humm... tried three of those and got the same results every time. Do you have an idea whats goin on here?

[@JohnAudioTech]

High performance opamps are often "fast" (high slew rate). If board layout isn't ideal they can oscillate. Also, a series resistor of around 100 Ohms should be used on the output for stability due to cable transmission line effects. The oscillation is HF but may cause audible effects you are hearing.

[@niklaswinter5160]

JohnAudioTech thanks for the quick answer :) I've set this up on a breadboard for testing it. Maybe that's the issue... But the lm833 is also a special audio op amp and does not humm. But I will try that resistor on the Output ^^

[@snaprollinpitts]

hey John, the output was about 4.5 volts RMS, is there a point when the input signal is too high for an amp?

[@JohnAudioTech]

It would depend on the amplifier's gain and the input signal voltage needed to drive it to clipping. This pre amp should have more than enough output to drive about any power amplifier to clipping. It has ample gain for most bench projects.

[@snaprollinpitts]

thank you John!!!

[@RobertKohut]

Nice!

[@saiprasad8078]

Hi can you please tell me which pot you have used (link) ?

[@standishgeezer]

Nice & simple. Have you tested the frequency range this preamp can handle John?

[@JohnAudioTech]

I found it became slew rate limited at something like 150KHz, if memory serves.

[@standishgeezer]

Thanks. I'm trying to get my head around 'gain bandwidth product' specs and it seems this ic should be capable of quite a high bandwidth if I keep the gain low.

[@RexxSchneider]

@@standishgeezer Once you start swinging volts at the output, the limiting factor is the slew-rate of the amp. The NE5532 has a unity-gain bandwidth of 10MHz, so you could expect a small signal gain of 10 to have a bandwidth approaching 1MHz, but its 9V/μs slew rate limits the large-signal output to the hundreds of KHz. The datasheet shows a large-signal bandwidth around 160KHz for ±10V supplies.

[@dannyasher3259]

Could something like this be used for a magnetic cartridge ?

[@Louis2282]

no because this is a universal preamp, for a magnetic cartridge you need RIAA equallisation

[@larryshaver3568]

the speakers in the cabinet sound great, what kind are they?

[@JohnAudioTech]

Dayton brand 8" woofers and dome tweeters (I don't recall the brand of them).

[@manFromPeterborough]

@@JohnAudioTech Dayton are good, I've just ordered the B652- AIR

[@philprice4324]

Would this be suitable as a phono preamp? Or would it require modification? thanks Phil

[@JohnAudioTech]

No. A phono preamp requires filter circuit with a specific slope. I built a one in another video.

[@darinbrunet4600]

Phil Price RIAA EQ filter is needed for phonograph use.

[@philprice4324]

JohnAudioTech Thanks John. I built this as a learning exercise and discovered it wasnt suitable as phono preamp. Will look for your other video.

[@philprice4324]

Darin Brunet Thanks Darin. Discovered this after making and testing. A good learning opportunity.

[@darinbrunet4600]

Good video, btw 🍻

[@zulkarnainkarim]

superb video sir.. but can i replace those 5532 with 4558 or others ? i want to make this for preamp ic tester. both ics are dual op amp right?

[@JohnAudioTech]

You can use most dual op amps as the 8 pin DIP is standard across many types.

[@darinbrunet4600]

NJM4558 is a good chip. I'd also try an OPA1612. Vanishingly low distortion.

[@zulkarnainkarim]

thank you sir

[@zulkarnainkarim]

thank you sir

[@darinbrunet4600]

zulkarnainkarim If you want a lesser expensive good quality opamp, try the NJM2068DD. 10k input resistor, 100R series res. 1.5k/1k feedback res. Very good performer. Download the data sheet. Readily available and CHEAP!

[@iceberg789]

cool ! but batteries will run out within few days every time.

[@JohnAudioTech]

If I forget to turn it off it will!

[@TomasSchertel]

Hi John. Can I build half circuit using a NE5534 for a mono amplifier?

[@JohnAudioTech]

Sure can!

[@TomasSchertel]

Hi... Thanks for reply. Do I need to change any component value?

[@JohnAudioTech]

Not if you want the same gain as my circuit.

[@anindyamitra5091]

👈 see this thumbnail, try to solder like this, it is way more neat and easy to troubleshoot!

[@senorcapitandiogenes2068]

I just made this amp exactly after the circuit diagram you showed. The audio sounds compessed and when I connect the ground wire from the headphones i get a loud repeating clicking sound. Anyone have any ideas?

[@JohnAudioTech]

This amp is not made for driving headphones. Minimum impedance should be around 500 Ohms. Repeating clicking sounds like oscillation. Something is not connected properly.

[@senorcapitandiogenes2068]

JohnAudioTech I am using headphones to check if it even puts out sound. I think I have some grounding issues. How is audio-input ground and audio-output ground connected?

[@senorcapitandiogenes2068]

JohnAudioTech Never mind, I found the problem. It's now working perfectly. I must thank you, thanks to you I can now listen to the vinyls my grandfather that recently passed away gave to me

[@JohnAudioTech]

Glad you got it sorted. Enjoy the music!

[@Tbonyandsteak]

3 V Rms is that not to much? if you have an effect that only need 600 mv

[@JohnAudioTech]

That's why I included the volume/level control.

[@Tbonyandsteak]

@@JohnAudioTech well I am a newbie ;) but is it not better if you want to build a more static system to adjust it more precise. You off course have a different need with it. I have noticed, when the volume is high it is also more transparent. Due to the lesser resistance. I mean if you can adjust the output the lesser resistance you would need, the more transparent sound. I think the reason i usually play loud is due to I want that clear sound. Would be nice if I could make it clear at lower volume. Behaps it is just a shitty gear i have had. XD Oh well the question gave the answer I guess. Still in learning process. Big Fan of you btw. John Thx for what you do, it is gold.

[@IceJackal1984]

share the circuit diagram

[@DiscoverRajivVlogs]

Hey, john do u have a cnc machine?? Great box.

[@JohnAudioTech]

No. All hand made.

[@DiscoverRajivVlogs]

@@JohnAudioTech Those plastic cuts are very good.

[@wd3574]

Nice! Where did you find the case?

[@JohnAudioTech]

I built it from pieces of black and grey tinted acrylic plastic.

[@Andrewatnanz]

Those Sunbeam batteries are cheap but have such a short lifespan its not worth the money.

[@TONY-gj3jl]

Per avere 1k d'impedenza, cosa devo aggiungere?

[@puriwatw.1323]

Can I use 4.7uF instead of 2.2uF?

[@JohnAudioTech]

It is a bit overkill but it will work.

[@puriwatw.1323]

@@JohnAudioTech How to increase the gain sir?

[@JohnAudioTech]

@@puriwatw.1323 Increase the ratio of the feedback resistors. Only set the gain to as much as you need because you will increase the noise and distortion with more gain.

[@1este11]

can i add a headphone out?

[@karlh.peterson8134]

not without modifications. The opamp does not have enough power drive capability to directly drive phones (see data sheet for load driving characteristics of opamp and your headphone specifications for ohms, these will be at least order of magnitude apart) Thus, depending on headphones the distortion will generally be very high. Adding a simple totem pole output stage to add power drive capability is easy though and would give fair performance, nothing stellar but okayish -60dB range maybe. Requires that you take negative feedback after totem pole output, this will somewhat compensate for crossover distortion which will otherwise destroy the performance. See web, tons of details.

[@rizsarwar2713]

hi i am looking for a small pocket type amp to make for ear phones with bass function. i am looking for best amp chip to use for low distortion and hiss.

[@SujusudhakarSuju]

Sir please send me pdf

[@TheSpazzattack95]

Just watching this vid .. u went under the input cap doesnt matter i dont no anything bout that buuttt!!!!.... i know physics and fields tho u putttt pnp on the neg side of ur board. So .. ur ecited pnp is rlly dropped because its not excited at the posative end.. its not quite pnp.. but is as its op.. but if u no fields well the layers of plates say in a voltage transformer it has plates that vibrater back and forth and that if it didnt vibrate would not create the field it does im prety sure.. as itd be negative at that time as under the board is a farrther away from the top wich is the fields the fields ar miniscullyyy hugee!!!

[@TheSpazzattack95]

Wich is like u said dropped cuase u dont want noise

[@TheSpazzattack95]

Tho im self taught and still learning soo much :) this stuff is a great passion of mine its all i think of lately :/ bought a high output alternator and started to look into physics and all things sound engineering starting like a hole year and half ago or maybe two now ..

[@TheSpazzattack95]

Ohh thoo thatd make for mor and less noise thoo but at pnp typ config but hmm how do u like that? Have u had it hooked up to a sub?

[@gettingoldsuckss]

Why is schematic backwards?! Standard is left to right isn't it?

[@MrTigger015]

Can I use 36k and 3,6k resistors?

[@JohnAudioTech]

Yes, but I would not go too much higher.

[@MrTigger015]

ok, I will do my best

[@darinbrunet4600]

MrTigger015 Remember it is the RATIO of the resistors, not the value. Keep them as low as you can to reduce Johnson noise. I would try 10k, 1k and check performance. Also, maybe change the input resistor from 20k to 10k. A portable player like iPod or cell phone output would have no prob driving a 10k load.