LINKS TO VIDEO ABOUT AUDIO END AMPLIFIERS LM 386 bass boost audio end amplifier (schematic & sound demo) ua-cam.com/video/pke1LIqoYrg/v-deo.html Decoupling & hum free audio amplifiers (schematics) ua-cam.com/video/0SoD3GlFH0s/v-deo.html Audio amplifier 400 mW special for bad Signal-Noise audio files ua-cam.com/video/e9P3cGBUA1s/v-deo.html 5-8 watt audio amplifier part 1 ua-cam.com/video/a8w2vEB9MJM/v-deo.html 5-8 watt audio amplifier part 2 ua-cam.com/video/U2sgiA1V1xs/v-deo.html IRF PE 50 MOSFET Class A audio amp 0,5 Watt output ua-cam.com/video/KrK9ufcZOT8/v-deo.html Audio signals transported over long wires (issues) ua-cam.com/video/ldtEAlsCXMw/v-deo.html The transistor series voltage regulator practice (hum-free) ua-cam.com/video/YL41FPH_H-s/v-deo.html How to make a mini audio stereo set part 1 ua-cam.com/video/4Lqjw9rbzJA/v-deo.html How to make a mini audio stereo set part 2 ua-cam.com/video/ZMXUip3i1zY/v-deo.html How to keep vintage audio amps from the 1970’s working ua-cam.com/video/C_9n9c3kHVo/v-deo.html Old school audio cinch plug switchbox ua-cam.com/video/IOiG6SDP-8E/v-deo.html Quiescent current alignment in audio class B amplifiers ua-cam.com/video/9Uw16td6F14/v-deo.html Prevent hum in homebrew audio amplifiers (earth issues) ua-cam.com/video/IsLEyx3nU9o/v-deo.html Solid state wiring in homebrew audio amplifiers ua-cam.com/video/Ne1TzmitJxk/v-deo.html Low tech electronic construction, part 1 ua-cam.com/video/4Nw4qZxd3Qo/v-deo.html Low tech electronic construction, part 2 ua-cam.com/video/ZYMyIsY-qgM/v-deo.html Low tech electronic construction, part 3 ua-cam.com/video/Of_Ug1ur0sI/v-deo.html Developing a 6 Watt stereo audio amp, part 1 ua-cam.com/video/DRjn7Al-wdc/v-deo.html Developing a 6 Watt stereo audio amp, part 2 ua-cam.com/video/FJiWGJnqO6w/v-deo.html Developing a 6 Watt stereo audio amp, part 3 ua-cam.com/video/6an9geeZkgk/v-deo.html Developing a 6 Watt stereo audio amp, part 4 ua-cam.com/video/Tk5_BE2mjlY/v-deo.html 2 transistor audio power booster 5-15 Watt ua-cam.com/video/TgvRE9eYXdQ/v-deo.html Background loudspeakers 0,5 Watt ua-cam.com/video/UQ3I0kLTsCI/v-deo.html Wall transformer audio amp 0,3 Watt ua-cam.com/video/Mtyuc-tNULs/v-deo.html Decoupling in audio amplifiers ua-cam.com/video/Mtyuc-tNULs/v-deo.html Radiofun232 on UA-cam (complete video index & links) ua-cam.com/video/xbgQ8T3oqh4/v-deo.html
LINKS TO HUM FREE POWER SUPPLIES FOR AUDIO (+ related subjects) Decoupling & hum free (silent) audio amplifiers ua-cam.com/video/0SoD3GlFH0s/v-deo.html How to make a good analog audio transistor pre amp, version 1 ua-cam.com/video/luBmY8SzGh0/v-deo.html Audio signals transported over long wires ua-cam.com/video/ldtEAlsCXMw/v-deo.html The transistor series voltage regulator practice (IMPORTANT) ua-cam.com/video/YL41FPH_H-s/v-deo.html How to make a small mini audio set (1-2 Watt) pt 2-1 ua-cam.com/video/ZMXUip3i1zY/v-deo.html How to make a small mini audio set (1-2 Watt) pt 2-2 ua-cam.com/video/4Lqjw9rbzJA/v-deo.html Find out a choke coil for a DC power supply ua-cam.com/video/dn-CDTy7cg4/v-deo.html Tips to make a High Voltage (120V-50mA) hum free power supply ua-cam.com/video/d71voqjK0Q4/v-deo.html Prevent hum in homebrew audio amplifiers ua-cam.com/video/IsLEyx3nU9o/v-deo.html How to test a power supply ua-cam.com/video/BeNoSmm3D_4/v-deo.html Developing a 6 Watt stereo audio amp. Part 1 (e.v.) ua-cam.com/video/DRjn7Al-wdc/v-deo.html O-34 V-2A power supply (IMPORTANT) ua-cam.com/video/-hXvM1svcdY/v-deo.html How to make a bridge (full wave) rectifier with 4 diodes ua-cam.com/video/6E8rULhY-1k/v-deo.html
This information is extremely helpful and easily understood. Having just begun to research the basics of audio electronics (as a hobbyist), I have easily found many schematics and "step-by-step" instructions, but in my experience so far, not so easily found are comprehensible explanations of how the components tangibly contribute to the overall function of the circuit. Thank you for taking the time to post these videos, I am looking forward to referencing your books, schematics 1 and 2. Thanks!
ua-cam.com/video/YL41FPH_H-s/v-deo.html This is also an informative video to tackle the "hum" issue. The most ennoying issue when you want to create audio amps yourself.
@Jonathan Suit Hi, I've bought some books from Ko Tilman via the Lulu book website, they are amazing,if you think his videos are good wait until you read his books, very,very interesting and educational with lots of useful circuits :)
Another great lesson. I will try your advice for the hum noise! I also had a lot of difficulty filtering the ripple of the mains split +/- power supply for my power amp at high current. Any tips?
Best circuits are here ua-cam.com/video/YL41FPH_H-s/v-deo.html say "capacitance multipliers" to press the ripple on the supply lead to its minimum. For a double power supply they must be made twice, one for the positive lead (NPN transistor/Darlington) and one for the negative lead (PNP transistor/Darlington). You loose supply current with this setup, they form 2 series regulators, they get warm and dissipate. I found many problems making a hum free double voltage power supply usable for high(er) currents, especially with the Darlington setup. The video's are on my channel. Keyword: "double power supply".
sir, i am long time admirer of your videos .At time11.43 u speak about input cap is reflected into out by the amount of amplification factor that is wounderful concept but pl give little more detail about that so that viewer can under stand fully.thank u.
The capacitor that the circuit, connected to the Emitter from the BD 139 "sees" is (say) 100 uF (at the base) multiplied by the amplification factor from the transistor, say 100 = 100 x 100=10000 uF. There is a video on my channel where this is all explained, go to my channel trailer "radiofun232 on UA-cam" and search there.
Hello and thank you for your time on this subject, but on your schematic are the AMPs POWER TRANSISTORS? With my AMP I have 2 C5198 NPN, and 2 A1941 PNP POWER TRANSISTORS. The system is rated at 1000W, but each POWER TRANSISTOR is rated at 100W . Anyway it has a lot of HUM so I"ve been trying to find away to stop it, and I would really like to use your method, but I"m not sure how to connect the POWER TRANSISTORS? On your schematic it shows the AMPs POSITIVE CONNECTION, and I gues the COLLECTER. Can you help me clarify this please? Thank you again for your time, and HAPPY NEW YEAR!!!!!!!
Sorry, but is more or less impossible to help without having seen the system that you have. But in my book "Schematics 2, audio amplifiers and loudspeaker boxes" (available via the website from Lulu, search for author Ko Tilman there) there is a lot of info.
Put a 1000 uF or higher value electrolytic capacitor over the voltage supply. When it is a double power supply: 2 electrolytics, one with its electrode to the +, the other with its electrode to the - and their other electrodes together to the 0. When there is another reason for oscillation: such a problem must be studied extensively with the help of an oscilloscope. Often it can be cured by making the input impedance of amplifiers lower with a bypass resistor between audio input socket in and ground (0 or minus) in the 1K-50 K range. Or by limiting the bandwidth of an audio amplifier by soldering a 470 pF capacitor between the audio input and ground (0 or minus). For stereo: everything 2 x.
Sir...i have subwoofer circuit with irfp 150 n 4 numbers of mosfet new....first i connect to 100 watt woofer my woofer gone..then service technician told that the negative side mosfet shorted ..i serviced and reconnect now its work for few seconds and distortion starting ....when i check i noticed that bc547 transister become hot and volume down with distortion .....power supply is 35 0 35V 10 amps....why its happenig...i know you are dont know about circuits ....Please help...
Sir....how can i earth all volume controls and transformers in a 7.1 assembled home theatre system ...? tda2030 bridged for Stereo and centre. Surrounds are la4508 dual ic subwoofer is tda 7294....
I don't know that without a schematic. But there are a lot of instructional video's on my channel, e.g. under "Links to videos about audio end amplifiers".
Sir, I have Diffrent problem from my La4508 dual ic amplifier ....its intermittently humming high frequency sound(2 seconds sound ) whether input signal is present or not....why....? a usb board is connected from the same power supply through lm7805 regulater...how can i fix this...?
Decoupling & hum free audio amplifiers (schematics) ua-cam.com/video/0SoD3GlFH0s/v-deo.html I think it oscillates due to unproper decoupling from the power supply, but without schematic and pictures about how it was made it is difficult to say.
I saw on the datasheet that the bandwidth from this chip is very high (50 KHz or 100 KHz). That makes it vulnerable for oscillations on high frequencies. You can try to limit the freq. band by bypassing the audio input to ground with a ceramic cap from 100-470 pF. You can also do a test with your fingers: use your hand as a resistor and test between which points on the circuit board the oscillation stops. Try e.g. a 1M resistor between these 2 points. You can also solder a 100 N capacitor (ceramic) directly (!) on the chip power supply pin to ground/mass. Or: take a 10 Ohm 10 Watt resistor from your power supply (say: 18 V) to the + pin from the chip and connect to that same + pin directly an electrolytic cap from 1000 uF to ground. Furthermore: the wiring must be made properly so that there is no feedback path from the output to the input. Buy my book: "Schematics 2, audio amplifiers and loudspeaker boxes" via the website from Lulu (author Ko Tilman) for more info.
I have experimented using LM386 on breadboard to make a basic amplifier but there is very strong hissing noise either when the music play or not ...and also when the music strong bass kicked in the sound on the speaker like knocking on a wood instead of good bass...do you have any idea whats the problem and how to fix it.
I think your amplifier is oscillating (on an not audible frequency or frequencies, say between 15 KHz and 30 KHz or higher) due to not enough decoupling in the power suppy line. You can see that when you study the Loudspeaker output on an oscilloscope.
Is it possible to decouple the power to an already made amplifier board? Assuming there is no pre-amp and only one stage of amplification, could you simply decouple the power coming into the board? Or must the decoupling be integrated into the circuit?
Yes, that is possible. It depends whether it is a power amp or a pre amp. And a schematic is needed or an idea how the existing power supply is made and works.
@radiofun232 Hi Ko @8.55 mins you draw the schematic for the decoupling unit with a transistor. This is my question the transistor amplifies the value of the capacitor by a factor or x 70, so 100uF x 70 = 7,000 uF in total, so if the circuit thinks it is seeing 7,000uF and not 100uF how is this possible when the capacitance is only 100uF,is it possible to amplify capacitance in this way and would it show on an oscilloscope the reduction in ripple exactly the same as it would if you actually used a 7,000 uF (or 6,800uF) capacitor.
Yes, see my earlier comment. When you put your scope to the output of such a series regulator (don't damage your scope, be sure the scope input is able to handle that voltage) you can see very good how the hum (sometimes even a small sawtooth signal caused by the diodes in the bridge rectifier, especially when the main capacitor has a too low value= for audio lower than 4700 uF) has disappeared. Interesting is also to connect a dummy load to your series regulator (heavy 20 Watt or so resistor, mimic the current that you need later in your electronic circuit) you can see that also under a load the hum stays away. By testing it in this way you can find out the ideal electrolytic capactitor from base to ground, given the max hum suppression (you don't need to make this elco to big, the power supply gets lazy when it has to deliver current suddenly, this relevant for audio amplifiers).
radiofun232 Is there a name for amplifying the capacitance or the theory of it? or the application,for example 4 diodes together in a power supply called a bridge rectifier, and 2 transistors after each other darlington pair,resistor and cap together called a RC filter or pi filter is there a name for this process of amplifying the capacitance by the factor of the hfe of the transistor?
As far as I know this effect is known in electronic theory as "the Miller effect" (but I could be wrong....). It has to do something/was invented by mr Miller during radar development in World War 2. I have to say that I am not completely sure and have to study that better, but anyway. I think you can find the Miller effect in Wikipedia.
Sir....do you know the power supply voltage of stk416-130 (180×3 channel) and stk433-260(60×3 channel)....? these boards are from a sony 5.1...its transformer is burn...its 720 w rms system ....filter capacitor value of bothbboards were 3300uf 50 volts dc...
Sir...Finally...i got it from internet....416 have vl.vh and ground ...ie 25 0 25 and 40 0 40 v ac and 433 have only vl 25 0 25...i already connect it but not working ...i think there are another pin connection coming from mother board thats mute .stand by.unregd 16 v and protect....mother board is gone....that amplifier board is actually removed from sony mhcgzr9d hi fi system ...now i am trying....!
@radiofun232 Hi Ko,at 5.22 mins the decoupling unit that says perfect at the bottom of the page,how would this connected in the diagram above? Does it simply connect in parallel across the supply rails then feeds to all circuits OR should there be 3 x of these perfect circuits at each point of the above diagram, for example 1 connected in parallel for the 1st pre amp and then another for the 2nd pre amp and a 3rd one for the end amp OR as i say should it just be connected into the main power rails then feeds all circuits and it will work fine. What is the way to connect it and FINALLY the transistor decoupling unit at the end of the video does this connect in all 3 stages or is it only connected in the power supply rails then fed to all 3?
Thanks. This is a kind of science. The most important thing is this: a kind of ""battery voltage + current"" has to be created for every electronic circuit in the whole, whether it is a power audio amp (1-5 A supply current at say 12-40V) or a pre amp (12 V or 40 V at 1 mA up to 3 mA).. In a galvanic battery circuit there is: no hum, a constant current (ideal) + constant voltage (ideal!!!) but that central idea has to be kept in mind when you make end amps or power amps. Hum-free power amps on 110 or 220 V AC (sec: 10 V to 40 V or more AC) can only be generated by good power supplies with transistors that press the hum level to its absolute minimum. Buy my book "Schematics 2, audio amplifiers and loudspeaker boxes"" for motre info. Ideally you can use 3 separate hum suppressors, but you can also use 1 hum suppressor and connect it to 3 or more electronic circuits, pre amps. It depends on how much current the pre amp stages take, not much in general. Again: buy my book. Anyway: with a BD 139 hum suppressor you can feed approx 100 pre amp stages, taking all 3 mA=100 x 3 = 300 mA.
radiofun232 Thanks Ko,I did already buy that boow,well the download version as the book wasn't available at that time :( which i relly wanted,so its downloaded on my laptop,i have to print out all the pages,so i will have a look at it. Thanks for the answer but im still not clear on this answer part. The Perfect circuit how would that be connected to the circuits in your video? would you make x 3 of them and connect them across the power rails to each individual circuit OR just make x 1 and connect it across the power rails before it then feeds to any circuits in the chain
OK, understood. Perhaps we can communicate further on this issue via radiofun232@gmail.com. Then I can take more time. Is it possible that you make a small drawing about the circuit(s) that you propose and send them to me via mail? Perhaps I can give a better and more elaborate reaction then.
Both options are possible. Ideal situation: 1) the stereo end-amplifier gets its own (separate) decoupling unit (1 time for 2 channels, could be 2 but one is enough) consisting of a hum-suppressor made with a power transistor. 2) the stereo pre amplifier gets its own decoupling unit, also consisting of 1 power-transistor hum suppressor. You can also use a 7812 for that purpose. But mail me, than I can make sketches from all kinds of supply options that work properly.
@radiofun232 iF the theory of amplifying the capacitance works then this could be used in large power supplies in audio amplifiers,obviously with larger transistors and higher wattage resistors and more powerful capacitors, so for example you could use a large 22,000uF capacitor then amplify it with maybe a 2N3055H to obtain a very large smoothing ripple free power supply. Would it still work on a larger scale or only useable on smaller lower voltage circuits. The hfe of the 2N3055H is about X 20 so would it generate 22,000uF X 20 = total capacitance of 440,000uF which would be extreme ripple rejection and NO HUM AT ALL,is this possible?
Yes, this is possible and it works indeed. I have tested this many times. Video on my channel: "the transistor series regulator practice" (when I recall it well). The circuit in that video suppress hum in an extreme way, the circuit on the middle of the page of that video is most practical. But: often 4700 uF give enough hum suppression but for sensitive audio (pre) amplifiers such a series regulator is necessary to remove even the slightest trace of hum. Problem for high currents circuits (end amps) is that the very big capacitor makes the current variations to the end amplifier sly (lazy). That could have an effect on the sound, but, anyway, I did not meet many problems with that approach. Everything must be tested, how the circuit acts in real.
radiofun232 This is a very good way to suppress hum and ripple and of course it would be cheaper and more efficient as the smoothing capacitor could be much smaller in uF's Possible draw back would be when very large demand of sound is requirred, i.e Bass kicks in very high this sudden surge in current would be taken up from the transistor and NOT the capacitor as in a normal power supply circuit and maybe the transistor in large audio power supplies would NOT react as quickly as the capacitor when compared side by side so maybe the sound could break up and clip :)
radiofun232 Aslo this circuit would be very useful in guitar amplifier circuits where there is always a problem with hum,it would suppress it extremely well
radiofun232 Tesla did experiments similar to this, experimenting with what electronic knowledge he had but pushing the boundaries further and further,i think many other possible inventions are yet to be discovered by manipulating electronics and the way they work
At @5:21 I don't understand why we need the 1M resistor and the 100 nF capacitor. Especially the resistor. Would you please explain a little or post a link to something that I can read?
More stability: suppressing from smal "peak" voltages on the power supply lead, especially on high frequencies. These peaks can be caused by electric motors. Also prevention from HF input (shortcut HF frequencies to ground, the electrolytic cap has no good HF properties regarding decoupling). The 1 M resistor helps to serve that aim and can discharge the electrolytic cap. Normally the electronic circuit discharges the cap, but anyway. All these issues can be made visible on the oscilloscope.
LINKS TO VIDEO ABOUT AUDIO END AMPLIFIERS LM 386 bass boost audio end amplifier (schematic & sound demo) ua-cam.com/video/pke1LIqoYrg/v-deo.html Decoupling & hum free audio amplifiers (schematics) ua-cam.com/video/0SoD3GlFH0s/v-deo.html Audio amplifier 400 mW special for bad Signal-Noise audio files ua-cam.com/video/e9P3cGBUA1s/v-deo.html 5-8 watt audio amplifier part 1 ua-cam.com/video/a8w2vEB9MJM/v-deo.html 5-8 watt audio amplifier part 2 ua-cam.com/video/U2sgiA1V1xs/v-deo.html IRF PE 50 MOSFET Class A audio amp 0,5 Watt output ua-cam.com/video/KrK9ufcZOT8/v-deo.html Audio signals transported over long wires (issues) ua-cam.com/video/ldtEAlsCXMw/v-deo.html The transistor series voltage regulator practice (hum-free) ua-cam.com/video/YL41FPH_H-s/v-deo.html How to make a mini audio stereo set part 1 ua-cam.com/video/4Lqjw9rbzJA/v-deo.html How to make a mini audio stereo set part 2 ua-cam.com/video/ZMXUip3i1zY/v-deo.html How to keep vintage audio amps from the 1970’s working ua-cam.com/video/C_9n9c3kHVo/v-deo.html Old school audio cinch plug switchbox ua-cam.com/video/IOiG6SDP-8E/v-deo.html Quiescent current alignment in audio class B amplifiers ua-cam.com/video/9Uw16td6F14/v-deo.html Prevent hum in homebrew audio amplifiers (earth issues) ua-cam.com/video/IsLEyx3nU9o/v-deo.html Solid state wiring in homebrew audio amplifiers ua-cam.com/video/Ne1TzmitJxk/v-deo.html Low tech electronic construction, part 1 ua-cam.com/video/4Nw4qZxd3Qo/v-deo.html Low tech electronic construction, part 2 ua-cam.com/video/ZYMyIsY-qgM/v-deo.html Low tech electronic construction, part 3 ua-cam.com/video/Of_Ug1ur0sI/v-deo.html Developing a 6 Watt stereo audio amp, part 1 ua-cam.com/video/DRjn7Al-wdc/v-deo.html Developing a 6 Watt stereo audio amp, part 2 ua-cam.com/video/FJiWGJnqO6w/v-deo.html Developing a 6 Watt stereo audio amp, part 3 ua-cam.com/video/6an9geeZkgk/v-deo.html Developing a 6 Watt stereo audio amp, part 4 ua-cam.com/video/Tk5_BE2mjlY/v-deo.html 2 transistor audio power booster 5-15 Watt ua-cam.com/video/TgvRE9eYXdQ/v-deo.html Background loudspeakers 0,5 Watt ua-cam.com/video/UQ3I0kLTsCI/v-deo.html Wall transformer audio amp 0,3 Watt ua-cam.com/video/Mtyuc-tNULs/v-deo.html Decoupling in audio amplifiers ua-cam.com/video/Mtyuc-tNULs/v-deo.html Radiofun232 on UA-cam (complete video index & links) ua-cam.com/video/xbgQ8T3oqh4/v-deo.html
LINKS TO VIDEO ABOUT AUDIO END AMPLIFIERS
LM 386 bass boost audio end amplifier (schematic & sound demo) ua-cam.com/video/pke1LIqoYrg/v-deo.html
Decoupling & hum free audio amplifiers (schematics) ua-cam.com/video/0SoD3GlFH0s/v-deo.html
Audio amplifier 400 mW special for bad Signal-Noise audio files ua-cam.com/video/e9P3cGBUA1s/v-deo.html
5-8 watt audio amplifier part 1 ua-cam.com/video/a8w2vEB9MJM/v-deo.html
5-8 watt audio amplifier part 2 ua-cam.com/video/U2sgiA1V1xs/v-deo.html
IRF PE 50 MOSFET Class A audio amp 0,5 Watt output ua-cam.com/video/KrK9ufcZOT8/v-deo.html
Audio signals transported over long wires (issues) ua-cam.com/video/ldtEAlsCXMw/v-deo.html
The transistor series voltage regulator practice (hum-free) ua-cam.com/video/YL41FPH_H-s/v-deo.html
How to make a mini audio stereo set part 1 ua-cam.com/video/4Lqjw9rbzJA/v-deo.html
How to make a mini audio stereo set part 2 ua-cam.com/video/ZMXUip3i1zY/v-deo.html
How to keep vintage audio amps from the 1970’s working ua-cam.com/video/C_9n9c3kHVo/v-deo.html
Old school audio cinch plug switchbox ua-cam.com/video/IOiG6SDP-8E/v-deo.html
Quiescent current alignment in audio class B amplifiers ua-cam.com/video/9Uw16td6F14/v-deo.html
Prevent hum in homebrew audio amplifiers (earth issues) ua-cam.com/video/IsLEyx3nU9o/v-deo.html
Solid state wiring in homebrew audio amplifiers ua-cam.com/video/Ne1TzmitJxk/v-deo.html
Low tech electronic construction, part 1 ua-cam.com/video/4Nw4qZxd3Qo/v-deo.html
Low tech electronic construction, part 2 ua-cam.com/video/ZYMyIsY-qgM/v-deo.html
Low tech electronic construction, part 3 ua-cam.com/video/Of_Ug1ur0sI/v-deo.html
Developing a 6 Watt stereo audio amp, part 1 ua-cam.com/video/DRjn7Al-wdc/v-deo.html
Developing a 6 Watt stereo audio amp, part 2 ua-cam.com/video/FJiWGJnqO6w/v-deo.html
Developing a 6 Watt stereo audio amp, part 3 ua-cam.com/video/6an9geeZkgk/v-deo.html
Developing a 6 Watt stereo audio amp, part 4 ua-cam.com/video/Tk5_BE2mjlY/v-deo.html
2 transistor audio power booster 5-15 Watt ua-cam.com/video/TgvRE9eYXdQ/v-deo.html
Background loudspeakers 0,5 Watt ua-cam.com/video/UQ3I0kLTsCI/v-deo.html
Wall transformer audio amp 0,3 Watt ua-cam.com/video/Mtyuc-tNULs/v-deo.html
Decoupling in audio amplifiers ua-cam.com/video/Mtyuc-tNULs/v-deo.html
Radiofun232 on UA-cam (complete video index & links) ua-cam.com/video/xbgQ8T3oqh4/v-deo.html
LINKS TO HUM FREE POWER SUPPLIES FOR AUDIO (+ related subjects)
Decoupling & hum free (silent) audio amplifiers ua-cam.com/video/0SoD3GlFH0s/v-deo.html
How to make a good analog audio transistor pre amp, version 1 ua-cam.com/video/luBmY8SzGh0/v-deo.html
Audio signals transported over long wires ua-cam.com/video/ldtEAlsCXMw/v-deo.html
The transistor series voltage regulator practice (IMPORTANT) ua-cam.com/video/YL41FPH_H-s/v-deo.html
How to make a small mini audio set (1-2 Watt) pt 2-1 ua-cam.com/video/ZMXUip3i1zY/v-deo.html
How to make a small mini audio set (1-2 Watt) pt 2-2 ua-cam.com/video/4Lqjw9rbzJA/v-deo.html
Find out a choke coil for a DC power supply ua-cam.com/video/dn-CDTy7cg4/v-deo.html
Tips to make a High Voltage (120V-50mA) hum free power supply ua-cam.com/video/d71voqjK0Q4/v-deo.html
Prevent hum in homebrew audio amplifiers ua-cam.com/video/IsLEyx3nU9o/v-deo.html
How to test a power supply ua-cam.com/video/BeNoSmm3D_4/v-deo.html
Developing a 6 Watt stereo audio amp. Part 1 (e.v.) ua-cam.com/video/DRjn7Al-wdc/v-deo.html
O-34 V-2A power supply (IMPORTANT) ua-cam.com/video/-hXvM1svcdY/v-deo.html
How to make a bridge (full wave) rectifier with 4 diodes ua-cam.com/video/6E8rULhY-1k/v-deo.html
Thank you for the clarity!
This information is extremely helpful and easily understood. Having just begun to research the basics of audio electronics (as a hobbyist), I have easily found many schematics and "step-by-step" instructions, but in my experience so far, not so easily found are comprehensible explanations of how the components tangibly contribute to the overall function of the circuit. Thank you for taking the time to post these videos, I am looking forward to referencing your books, schematics 1 and 2. Thanks!
You are welcome, good to hear that. I learned it the hard way... It took a long time to find answers to these issues by doing experiments.
ua-cam.com/video/YL41FPH_H-s/v-deo.html This is also an informative video to tackle the "hum" issue. The most ennoying issue when you want to create audio amps yourself.
@Jonathan Suit Hi, I've bought some books from Ko Tilman via the Lulu book website, they are amazing,if you think his videos are good wait until you read his books, very,very interesting and educational with lots of useful circuits :)
You always have very good information
thank you for video
Very well explained and descriptive video.
Thanks so very much for making it. 🎶🔊🙂
You are welcome, good to hear that.
very good information. Thanks for sharing your knowledge.
Great video, thanks for sharing
Another great lesson. I will try your advice for the hum noise! I also had a lot of difficulty filtering the ripple of the mains split +/- power supply for my power amp at high current. Any tips?
Best circuits are here ua-cam.com/video/YL41FPH_H-s/v-deo.html
say "capacitance multipliers" to press the ripple on the supply lead to its minimum. For a double power supply they must be made twice, one for the positive lead (NPN transistor/Darlington) and one for the negative lead (PNP transistor/Darlington). You loose supply current with this setup, they form 2 series regulators, they get warm and dissipate. I found many problems making a hum free double voltage power supply usable for high(er) currents, especially with the Darlington setup. The video's are on my channel. Keyword: "double power supply".
Very usefull info, thanks, I have an TDA7388 and I want to build an end amp, not yet sure how to do the pre amp
There are many pre-amp based circuits on the Web to choose or buy one on line...
sir, i am long time admirer of your videos .At time11.43 u speak about input cap is reflected into out by the amount of amplification factor that is wounderful concept but pl give little more detail about that so that viewer can under stand fully.thank u.
The capacitor that the circuit, connected to the Emitter from the BD 139 "sees" is (say) 100 uF (at the base) multiplied by the amplification factor from the transistor, say 100 = 100 x 100=10000 uF. There is a video on my channel where this is all explained, go to my channel trailer "radiofun232 on UA-cam" and search there.
Very informativ. TY
Hello and thank you for your time on this subject, but on your schematic are the AMPs POWER TRANSISTORS? With my AMP I have 2 C5198 NPN, and 2 A1941 PNP POWER TRANSISTORS. The system is rated at 1000W, but each POWER TRANSISTOR is rated at 100W . Anyway it has a lot of HUM so I"ve been trying to find away to stop it, and I would really like to use your method, but I"m not sure how to connect the POWER TRANSISTORS? On your schematic it shows the AMPs POSITIVE CONNECTION, and I gues the COLLECTER. Can you help me clarify this please? Thank you again for your time, and HAPPY NEW YEAR!!!!!!!
Sorry, but is more or less impossible to help without having seen the system that you have. But in my book "Schematics 2, audio amplifiers and loudspeaker boxes" (available via the website from Lulu, search for author Ko Tilman there) there is a lot of info.
How to fix Motorboating noise problem in Tea2025 amp configured in Bridge mode ?
Put a 1000 uF or higher value electrolytic capacitor over the voltage supply. When it is a double power supply: 2 electrolytics, one with its electrode to the +, the other with its electrode to the - and their other electrodes together to the 0. When there is another reason for oscillation: such a problem must be studied extensively with the help of an oscilloscope. Often it can be cured by making the input impedance of amplifiers lower with a bypass resistor between audio input socket in and ground (0 or minus) in the 1K-50 K range. Or by limiting the bandwidth of an audio amplifier by soldering a 470 pF capacitor between the audio input and ground (0 or minus). For stereo: everything 2 x.
@@radiofun232 Thank you Sir :-)
Cool, interesting
Lechoslowianin hoo
Sir...i have subwoofer circuit with irfp 150 n 4 numbers of mosfet new....first i connect to 100 watt woofer my woofer gone..then service technician told that the negative side mosfet shorted ..i serviced and reconnect now its work for few seconds and distortion starting ....when i check i noticed that bc547 transister become hot and volume down with distortion .....power supply is 35 0 35V 10 amps....why its happenig...i know you are dont know about circuits ....Please help...
Sorry, but I cannot help you. It is impossible to take a conclusion on the basis of your information.
Sir.its ok....the problem is high voltage 35 dc is enough...
Sir....how can i earth all volume controls and transformers in a 7.1 assembled home theatre system ...? tda2030 bridged for Stereo and centre. Surrounds are la4508 dual ic subwoofer is tda 7294....
I don't know that without a schematic. But there are a lot of instructional video's on my channel, e.g. under "Links to videos about audio end amplifiers".
Sir, I have Diffrent problem from my La4508 dual ic amplifier ....its intermittently humming high frequency sound(2 seconds sound ) whether input signal is present or not....why....? a usb board is connected from the same power supply through lm7805 regulater...how can i fix this...?
Decoupling & hum free audio amplifiers (schematics) ua-cam.com/video/0SoD3GlFH0s/v-deo.html
I think it oscillates due to unproper decoupling from the power supply, but without schematic and pictures about how it was made it is difficult to say.
I saw on the datasheet that the bandwidth from this chip is very high (50 KHz or 100 KHz). That makes it vulnerable for oscillations on high frequencies. You can try to limit the freq. band by bypassing the audio input to ground with a ceramic cap from 100-470 pF. You can also do a test with your fingers: use your hand as a resistor and test between which points on the circuit board the oscillation stops. Try e.g. a 1M resistor between these 2 points. You can also solder a 100 N capacitor (ceramic) directly (!) on the chip power supply pin to ground/mass. Or: take a 10 Ohm 10 Watt resistor from your power supply (say: 18 V) to the + pin from the chip and connect to that same + pin directly an electrolytic cap from 1000 uF to ground. Furthermore: the wiring must be made properly so that there is no feedback path from the output to the input. Buy my book: "Schematics 2, audio amplifiers and loudspeaker boxes" via the website from Lulu (author Ko Tilman) for more info.
Thanks for your replay sir...
Sir...finally i found the problem .....corrosion on some resisters and jumper connections.....now its work awesome....
OK, good to hear that!
I have experimented using LM386 on breadboard to make a basic amplifier but there is very strong hissing noise either when the music play or not ...and also when the music strong bass kicked in the sound on the speaker like knocking on a wood instead of good bass...do you have any idea whats the problem and how to fix it.
I think your amplifier is oscillating (on an not audible frequency or frequencies, say between 15 KHz and 30 KHz or higher) due to not enough decoupling in the power suppy line. You can see that when you study the Loudspeaker output on an oscilloscope.
Is it possible to decouple the power to an already made amplifier board? Assuming there is no pre-amp and only one stage of amplification, could you simply decouple the power coming into the board?
Or must the decoupling be integrated into the circuit?
Yes, that is possible. It depends whether it is a power amp or a pre amp. And a schematic is needed or an idea how the existing power supply is made and works.
@radiofun232 Hi Ko @8.55 mins you draw the schematic for the decoupling unit with a transistor.
This is my question the transistor amplifies the value of the capacitor by a factor or x 70, so 100uF x 70 = 7,000 uF in total, so if the circuit thinks it is seeing 7,000uF and not 100uF how is this possible when the capacitance is only 100uF,is it possible to amplify capacitance in this way and would it show on an oscilloscope the reduction in ripple exactly the same as it would if you actually used a 7,000 uF (or 6,800uF) capacitor.
Yes, see my earlier comment. When you put your scope to the output of such a series regulator (don't damage your scope, be sure the scope input is able to handle that voltage) you can see very good how the hum (sometimes even a small sawtooth signal caused by the diodes in the bridge rectifier, especially when the main capacitor has a too low value= for audio lower than 4700 uF) has disappeared. Interesting is also to connect a dummy load to your series regulator (heavy 20 Watt or so resistor, mimic the current that you need later in your electronic circuit) you can see that also under a load the hum stays away. By testing it in this way you can find out the ideal electrolytic capactitor from base to ground, given the max hum suppression (you don't need to make this elco to big, the power supply gets lazy when it has to deliver current suddenly, this relevant for audio amplifiers).
radiofun232
Is there a name for amplifying the capacitance or the theory of it? or the application,for example 4 diodes together in a power supply called a bridge rectifier, and 2 transistors after each other darlington pair,resistor and cap together called a RC filter or pi filter is there a name for this process of amplifying the capacitance by the factor of the hfe of the transistor?
ua-cam.com/video/YL41FPH_H-s/v-deo.html
As far as I know this effect is known in electronic theory as "the Miller effect" (but I could be wrong....). It has to do something/was invented by mr Miller during radar development in World War 2. I have to say that I am not completely sure and have to study that better, but anyway. I think you can find the Miller effect in Wikipedia.
Sir....do you know the power supply voltage of stk416-130 (180×3 channel) and stk433-260(60×3 channel)....? these boards are from a sony 5.1...its transformer is burn...its 720 w rms system ....filter capacitor value of bothbboards were 3300uf 50 volts dc...
No sorry, this is too specific. Take notice of the schematic, possibly you can find that on the internet.
Sir...Finally...i got it from internet....416 have vl.vh and ground ...ie 25 0 25 and 40 0 40 v ac and 433 have only vl 25 0 25...i already connect it but not working ...i think there are another pin connection coming from mother board thats mute .stand by.unregd 16 v and protect....mother board is gone....that amplifier board is actually removed from sony mhcgzr9d hi fi system ...now i am trying....!
ok
@radiofun232 Hi Ko,at 5.22 mins the decoupling unit that says perfect at the bottom of the page,how would this connected in the diagram above?
Does it simply connect in parallel across the supply rails then feeds to all circuits OR should there be 3 x of these perfect circuits at each point of the above diagram, for example 1 connected in parallel for the 1st pre amp and then another for the 2nd pre amp and a 3rd one for the end amp OR as i say should it just be connected into the main power rails then feeds all circuits and it will work fine.
What is the way to connect it and FINALLY the transistor decoupling unit at the end of the video does this connect in all 3 stages or is it only connected in the power supply rails then fed to all 3?
Thanks. This is a kind of science. The most important thing is this: a kind of ""battery voltage + current"" has to be created for every electronic circuit in the whole, whether it is a power audio amp (1-5 A supply current at say 12-40V) or a pre amp (12 V or 40 V at 1 mA up to 3 mA).. In a galvanic battery circuit there is: no hum, a constant current (ideal) + constant voltage (ideal!!!) but that central idea has to be kept in mind when you make end amps or power amps. Hum-free power amps on 110 or 220 V AC (sec: 10 V to 40 V or more AC) can only be generated by good power supplies with transistors that press the hum level to its absolute minimum. Buy my book "Schematics 2, audio amplifiers and loudspeaker boxes"" for motre info. Ideally you can use 3 separate hum suppressors, but you can also use 1 hum suppressor and connect it to 3 or more electronic circuits, pre amps. It depends on how much current the pre amp stages take, not much in general. Again: buy my book. Anyway: with a BD 139 hum suppressor you can feed approx 100 pre amp stages, taking all 3 mA=100 x 3 = 300 mA.
radiofun232
Thanks Ko,I did already buy that boow,well the download version as the book wasn't available at that time :( which i relly wanted,so its downloaded on my laptop,i have to print out all the pages,so i will have a look at it.
Thanks for the answer but im still not clear on this answer part.
The Perfect circuit how would that be connected to the circuits in your video? would you make x 3 of them and connect them across the power rails to each individual circuit OR just make x 1 and connect it across the power rails before it then feeds to any circuits in the chain
OK, understood. Perhaps we can communicate further on this issue via radiofun232@gmail.com. Then I can take more time. Is it possible that you make a small drawing about the circuit(s) that you propose and send them to me via mail? Perhaps I can give a better and more elaborate reaction then.
Both options are possible. Ideal situation: 1) the stereo end-amplifier gets its own (separate) decoupling unit (1 time for 2 channels, could be 2 but one is enough) consisting of a hum-suppressor made with a power transistor. 2) the stereo pre amplifier gets its own decoupling unit, also consisting of 1 power-transistor hum suppressor. You can also use a 7812 for that purpose. But mail me, than I can make sketches from all kinds of supply options that work properly.
radiofun232
ok Ko,i will send private email, Rob
@radiofun232 iF the theory of amplifying the capacitance works then this could be used in large power supplies in audio amplifiers,obviously with larger transistors and higher wattage resistors and more powerful capacitors, so for example you could use a large 22,000uF capacitor then amplify it with maybe a 2N3055H to obtain a very large smoothing ripple free power supply.
Would it still work on a larger scale or only useable on smaller lower voltage circuits.
The hfe of the 2N3055H is about X 20 so would it generate 22,000uF X 20 = total capacitance of 440,000uF which would be extreme ripple rejection and NO HUM AT ALL,is this possible?
Yes, this is possible and it works indeed. I have tested this many times. Video on my channel: "the transistor series regulator practice" (when I recall it well). The circuit in that video suppress hum in an extreme way, the circuit on the middle of the page of that video is most practical. But: often 4700 uF give enough hum suppression but for sensitive audio (pre) amplifiers such a series regulator is necessary to remove even the slightest trace of hum. Problem for high currents circuits (end amps) is that the very big capacitor makes the current variations to the end amplifier sly (lazy). That could have an effect on the sound, but, anyway, I did not meet many problems with that approach. Everything must be tested, how the circuit acts in real.
radiofun232
This is a very good way to suppress hum and ripple and of course it would be cheaper and more efficient as the smoothing capacitor could be much smaller in uF's
Possible draw back would be when very large demand of sound is requirred, i.e Bass kicks in very high this sudden surge in current would be taken up from the transistor and NOT the capacitor as in a normal power supply circuit and maybe the transistor in large audio power supplies would NOT react as quickly as the capacitor when compared side by side so maybe the sound could break up and clip :)
radiofun232
Aslo this circuit would be very useful in guitar amplifier circuits where there is always a problem with hum,it would suppress it extremely well
radiofun232
Tesla did experiments similar to this, experimenting with what electronic knowledge he had but pushing the boundaries further and further,i think many other possible inventions are yet to be discovered by manipulating electronics and the way they work
Yes, indeed.
At @5:21 I don't understand why we need the 1M resistor and the 100 nF capacitor. Especially the resistor. Would you please explain a little or post a link to something that I can read?
More stability: suppressing from smal "peak" voltages on the power supply lead, especially on high frequencies. These peaks can be caused by electric motors. Also prevention from HF input (shortcut HF frequencies to ground, the electrolytic cap has no good HF properties regarding decoupling). The 1 M resistor helps to serve that aim and can discharge the electrolytic cap. Normally the electronic circuit discharges the cap, but anyway. All these issues can be made visible on the oscilloscope.
Thanks a lot sir!
See also ua-cam.com/video/LkotuL57U8I/v-deo.html
LINKS TO VIDEO ABOUT AUDIO END AMPLIFIERS
LM 386 bass boost audio end amplifier (schematic & sound demo) ua-cam.com/video/pke1LIqoYrg/v-deo.html
Decoupling & hum free audio amplifiers (schematics) ua-cam.com/video/0SoD3GlFH0s/v-deo.html
Audio amplifier 400 mW special for bad Signal-Noise audio files ua-cam.com/video/e9P3cGBUA1s/v-deo.html
5-8 watt audio amplifier part 1 ua-cam.com/video/a8w2vEB9MJM/v-deo.html
5-8 watt audio amplifier part 2 ua-cam.com/video/U2sgiA1V1xs/v-deo.html
IRF PE 50 MOSFET Class A audio amp 0,5 Watt output ua-cam.com/video/KrK9ufcZOT8/v-deo.html
Audio signals transported over long wires (issues) ua-cam.com/video/ldtEAlsCXMw/v-deo.html
The transistor series voltage regulator practice (hum-free) ua-cam.com/video/YL41FPH_H-s/v-deo.html
How to make a mini audio stereo set part 1 ua-cam.com/video/4Lqjw9rbzJA/v-deo.html
How to make a mini audio stereo set part 2 ua-cam.com/video/ZMXUip3i1zY/v-deo.html
How to keep vintage audio amps from the 1970’s working ua-cam.com/video/C_9n9c3kHVo/v-deo.html
Old school audio cinch plug switchbox ua-cam.com/video/IOiG6SDP-8E/v-deo.html
Quiescent current alignment in audio class B amplifiers ua-cam.com/video/9Uw16td6F14/v-deo.html
Prevent hum in homebrew audio amplifiers (earth issues) ua-cam.com/video/IsLEyx3nU9o/v-deo.html
Solid state wiring in homebrew audio amplifiers ua-cam.com/video/Ne1TzmitJxk/v-deo.html
Low tech electronic construction, part 1 ua-cam.com/video/4Nw4qZxd3Qo/v-deo.html
Low tech electronic construction, part 2 ua-cam.com/video/ZYMyIsY-qgM/v-deo.html
Low tech electronic construction, part 3 ua-cam.com/video/Of_Ug1ur0sI/v-deo.html
Developing a 6 Watt stereo audio amp, part 1 ua-cam.com/video/DRjn7Al-wdc/v-deo.html
Developing a 6 Watt stereo audio amp, part 2 ua-cam.com/video/FJiWGJnqO6w/v-deo.html
Developing a 6 Watt stereo audio amp, part 3 ua-cam.com/video/6an9geeZkgk/v-deo.html
Developing a 6 Watt stereo audio amp, part 4 ua-cam.com/video/Tk5_BE2mjlY/v-deo.html
2 transistor audio power booster 5-15 Watt ua-cam.com/video/TgvRE9eYXdQ/v-deo.html
Background loudspeakers 0,5 Watt ua-cam.com/video/UQ3I0kLTsCI/v-deo.html
Wall transformer audio amp 0,3 Watt ua-cam.com/video/Mtyuc-tNULs/v-deo.html
Decoupling in audio amplifiers ua-cam.com/video/Mtyuc-tNULs/v-deo.html
Radiofun232 on UA-cam (complete video index & links) ua-cam.com/video/xbgQ8T3oqh4/v-deo.html
See also ua-cam.com/video/YL41FPH_H-s/v-deo.html