Thoughts on these audio amp circuits?

[c_mitra]

.... some areas of audio are so full of misguided myths and ideas that you can end up going down a slippery slope.....

Sad but true.

Another problem is that most circuits come without elaborate detailed explanations and functional roles. As if we are trying to make a solderman rather than an engineer.

 

[Audioguru]

I always use laptops as the input source, with the gain it had originally its now really low when used in doors but when compared to other amplifiers its significantly lower has less mid range frequencies

Maybe you are using the headphones output of the laptop instead of the line outputs?
The mid frequencies from this amplifier are perfect. The other amplifiers probably boost the mid frequencies. The tone controls on my sound systems are always set to no boost and no cut because my speakers are good. If your speakers are mounted above the floor then you hear the original sound plus a reflection from the floor that has a longer path causing phase shift and cancellation of mid frequencies.

I wanted to just send the link to the datasheet but seems I cannot post links here

Do not post a link to a datasheet that might disappear. Instead, download the datasheet and attach it here.

 

[KlausST]

Hi,

I wanted to just send the link to the datasheet but seems I cannot post links here

A link to the datasheet is O.K. But please use a link to the datasheet at the manufacturer's internet site.

Just copy the url address to the PDF from the browser and paste it in your post.
Or when you see a link to the datasheet then move over an press right mouse button and "copy url"...then paste it inyour post.

Usually its like "http://...*.pdf" or "https://...*.pdf" .
The forum software automatically generates a link.

Klaus

 

[Enzy]

what is the purpose of the switch at pin 17?

When making this can I keep the circuit closed?

 

[FvM]

what is the purpose of the switch at pin 17

Well explained in the datasheet, search for "contour". See also https://en.wikipedia.org/wiki/Loudness_compensation

 

[Audioguru]

The TDA1524 tone controls IC is obsolete and not made anymore. The two largest electronic parts distributors in North America do not have any.

 

[Enzy]

Ok what about the Lm1036 is that outdated also.

 

[Audioguru]

One opamp can make a good Baxandall bass and treble tone controls circuit instead of looking for an obsolete IC.

 

[Enzy]

I mentioned 1 Ic and I was told its obsolete and I mentioned lm1036 so now I am asking if thats obsolete... the opamps that are avaliable to me I have tried them and they all sound trashy I just wanted to try something else.

If its case I can use an opamp to build a good preamp cant I get a proper schematic from one of you guys, I have asked before but didnt get anything so I have to try to find some and ask about them.

 

[Audioguru]

You do not show what part of the world you are in. I buy electronic parts from the two largest electronic parts distributors in North America. Digikey shows that they have no LM1036 ICs in stock but they can get some if you buy 236 of them. Newark has 248 of them in stock. Texas Instruments (they bought National Semiconductor who invented the LM series of ICs) say they have some in stock but they are not made anymore.

There are thousands of excellent audio opamps produced, they sound perfect.

 

[Enzy]

I am in Jamaica. Your saying that but still not showing me any that's why I keep asking about random chips, both chips that are outdated still sell in my country yes I know it can be outdated and some people still have left overs, but that's why I said since there are so may could you provide a link to a schematic or something.

 

[Audioguru]

I had a nice honeymoon in Jamaica 38 years ago.
You can find circuits using the obsolete tone controls ICs on their datasheets.
Here is a link to a good Baxandall bass and treble tone controls circuit. **broken link removed**
Any dual audio opamp can be used like a TL072 or an OPA2134.

 

[Enzy]

that's nice well I happen to hear about electronics guys out here that does building but we are so secretive out here and stuck up with information that I can never meet any them out here but what I know for sure is that we mainly do repairs to electronics out here, we don't build there isn't even a factory out here for any electronic building, even if you see it they only buy stuff from china and re-brand it.

Its something I love so I am practicing daily and because I have to practice everything at once its so much reading and so time consuming and time is what im short of, I also want to stop using VERO boards so I trying to do Etching and thats tough I happen to draw my circuits in a software I used called circuit wizard but cant seem to understand fully how to put in the layers I need meaning I don't think there is a copper layer or copper pads ect, I always see those things missing when I try to use some software's to view the file.

 

[KlausST]

Hi,

An idea about digital audio...

Many years ago a built my own active speakers. I read a lot about filters and build a lot of active filter circuits with adjusted gain, filter frequency, filter characteristic...

Recently I bought an evaluation board ADAU1701MINIZ, it includes a DSP with digital and analog IO.
It was faszinating to see how simple it was with the graphical interface to do all the filter adjustemts within minutes.
I did a lot of experiments with this board, it was a great fun.
Even if one likes to use discrete filters...it's a fast method to find the filter parameters.

And "filters" are only one of many possible applications for digital signal processing.

If you want to build audio circuits in the future then - sooner or later - you will come to digital audio processing.

Maybe it's too soon now, maybe not.
For sure you need to learn the "analog basics" first. But digital will be the (your?) future.

Klaus

 

[Enzy]

If I am to learn about analog electronics how do you think I should start, meaning do you have anything that you recommend me to start with like a specific online article. Also I know these studies take a while to grasp so doing the basics of analog I would still like to have an idea where to stop because I know these readings are never ending

 

[KlausST]

Hi,

I know these readings are never ending

True

Maybe the best way to start is to focus on one thing.

For example "power amplifiers".
* What different types? their benefits and drawbacks. (research, reading)
* How do they work. priciples only, don´t go into deep details (research, reading)
* Find out what is your favourite.
* focus on the favourite. Now go into details. Learn every single part and it´s role. Learn to calculate the part values. Try to optimize the circuit. One circuit. (development, physics, mathematics, reading, reading, reading)
* Add new features to the circuit (volume control, tone control, clipping detector, overheat protection, DC protection, make it short circuit proof... and so on) (development)
* Make it your own circuit. With your ideas.

Klaus

 

[Enzy]

I occasional do readings on the different classes but since you told me to check them out and make a choice I was thinking for smaller setting low power I would use class AB amplifier like how I have been using the Tda7293 for the longest while but what I wanted to do for higher power was to use class D amplifiers I even selected a chip so far that seems to be popular with making class D amplifier and also inverters which I plan to make both so I plan to get used to that chip and it has a basic schematic in its datasheet that you guys could check out I will do more reading to see all that I can figure out.

Its the Irs2092

 

[Audioguru]

The datasheet for the IRS2092 Mosfet driver IC shows no spec's for a class-D audio amplifier. The spec's are on a datasheet for a reference circuit design called IRAaudamp5. It produces 100W into 4 ohms with low distortion or 120W with a little clipping distortion. Its frequency response cuts 20kHz a little with a 4 ohm load or boosts 20kHz a little then cuts higher frequencies with an 8 ohm load.

They do not say or show full power with an 8 ohm load but it is probably 50W to 60W with the plus and minus 35V power supply also used for the 4 ohm load.

 

[Enzy]

I refer to it as class D because I see alot of circuits in forums that are said to be class D and thats the chip they used. But I would take a recommendation for a chip you have used a DIP.

 

[Enzy]

Class D amplifier project

I found 2 schematics can you guys assess them and check if they are actually working amplifiers both boards have pcb designed for them also.



I want to Etch the 1000w version but parts would cost me a bit of cash so I want to verify.