10 Watt classical Audio amplifier made with the TL 071 CP Opamp, working now on 20 Volt demo/schem

Please read the complete description of this video in the textbox. For the best and most complete information about how to make a simple audio amplifier for (say) 10 Watt out. And more...Also: read the comments section.....

This video, now, 14 May 2025, has a quite long history. Around 8 May 2025 I wanted to make a series of video’s about “how to” develop a classical audio amplifier (1970s-1980’s). It was ment as a kind of “educational” project, for people interested in these matters.

But the final video (10 Watt audio amplifier with a 741 Opamp) went (kind of) “viral”, after say 2000 views. I had not expected that at all, after such a short time on YouTube.

That say first video/complete schematic is here
https://youtu.be/xd9_EoTdk-A?si=JyZWIphUVC089hep

Links to earlier video's can be found in the description the + IN the COMMENTS section there.

So I had to justify myself, also having seen the critical comments of a few YouTubers. Problem with these reactions is that we could step into the (say) “religion” of audio and audio amplification.

I have, in that regard, a kind of “simple” (basic) approach, that can be found in my book “Schematics 2, Audio amplifiers and loudspeaker boxes”, where I layed dowm my audio experiences when making many audio amplifiers since (say) 1974.

And some comments come from people (as far as I could see on their YouTube Channels) that have no experience or knowledge of making audio amplifiers in practice and/or no knowledge about the subject, thus how “audio” works. Frequency bands, distortion, sensitivity of the human ear, properties of loudspeakers and LS boxes, audio filters, etc.

That is also the problem of (say) the “religious approach” on the sound of audio amplifiers, pre-amplifiers, HQ amplifiers, certain loudspeaker boxes, etc.

Anyway: I don’t want to dive deep into this issue. Sound (and how a certain audio (HiFi) sound system “sounds” in practice) is for a big part a “personal thing”. Of course: minimal distortion (of all kinds) in pre-amps and end-amps is “key”.

In the circuit that I publish now & here (14 May 2025) the 741 Chip is replaced with the TL 071 CP Chip, a (modern…) FET Opamp. Please note (important): the maximum voltage is now (with that TL071 Chip) 24 Volt. Not 34 Volt or 35 Volt. I used in the demo 20 Volt.

With a better slew rate (compared to the 741) and a higher frequency-bandwidth product (say 5 MC). That is key for a proper amplification of high frequencies.

Does the TL 071 CP work better? Judge for yourself.

My opinion: slightly better… No very big differences. Somewhat better amplification on the higher audio frequencies (above 14 KC). Though the bias is as critical as via the 741, anyway. Much more info and a sound demonstration is in the video.

Music is (for 2 seconds) “Who’d Have Known” from Lily Allen
And: “In Albany New York by the 127 ers”.

Thus, again: that 1 M potmeter biases the whole amplifier completely on the pure (or not) amplification of audio. Test, try, set it to the right position (used with a supply voltage on now (14 May 2025, with that TL 071 Opamp) between 18 Volt and 24 Volt, while listening to audio.

When the audio is pure on a fixed supply voltage “X”: take the 1 M potmeter out, measure its resistances (wiper to up and to down) and solder fixed value resistors into the circuit, at the chosen supply voltage.

Then everything is properly aligned. More experiments or good circuits? Try e.g. the TDA 2615.

The sound of the TDA 2615 Chip is extemely pure (on say 4-6 Watt) and it is stable and easy to handle for amateurs and professionals. The relevant video is here:

https://youtu.be/1id_cNdDLvs

My You Tube channel trailer is here: https://youtu.be/xbgQ8T3oqh4?si=ELOGHT24f7LXI_wd

Type there the keywords that you like about audio/radio things in the “looking glass” = search function” and give “enter”. Via that you can the right info under my 1600 video's that I published. My books are available via the website of "LULU”, Search for author “Ko Tilman” there.
Link will follow.

Upload 14 May 2025.

IMPORTANT: the bias potmeter (1M) relates to the input level potmeter = the level of the audio input. The amplifier is very sensitive, say 200 mV audio in for completely driven out at 10 Watt on 20 Volt. That is why you see these oscilloscope views.

And, please: no "religious" critical comments on the bad properties of the 741 Chip, its limited audio bandwidth or frequency bandwidth product (ony 1 MC....!?), its low slew rate, that it is very old school, etc, etc, when your YT Channel shows that you have never made any electronic circuit or audio amplifier. These comments will be deleted in that case: when you do not show practical idea's or have really made electronic circuits. And/or in another way show that you don't know what you are talking about, thus: about electronics. Sorry to say....17 May 2025.

Видео 10 Watt classical Audio amplifier made with the TL 071 CP Opamp, working now on 20 Volt demo/schem канала radiofun232