Introduction: DIY Portable HiFi Amplifier (2x30w, Class AB)

Picture of DIY Portable HiFi Amplifier (2x30w, Class AB)

I've made a portable amplifier that uses a TDA7394 as its main IC chip. It's a Class-T amplifier look alike. There's also a hidden (internal) tone control circuit built with it. I posted it to inspire most of the people who asks me about making a "Class-T" amplifier, so I thought of making a Class AB-A amplifier instead. A Class AB amplifier has a fully symmetrical structure, this mean the sine waves (electric pulses) produces a + and - output.

Too bad I had a late documentation, that's why I only have a few pictures of the steps and procedures. If I make another one, I'l promise to fully document my amplifier as a step-by-step instructable.

My version works well with any wall wart, with a rating of: 12-28 volts, 1-5 Amperes, Switching-Transformer type.
I've also provided a schematic diagram of the amplifier. 

I hope you like it !


agis68 (author)2012-11-27

E-X-C-E-L-L-E-N-T Project.....

xaviert22 (author)2012-10-29

Very well done! I will definitely plan on building this someday.

jaagut (author)2013-02-27


in the schematic i found 1.5M resistor but it was not in the parts list.
checking the material bill against the schematic, it seemed like this is the 1.5K resistor. am i correct?

ASCAS (author)jaagut2013-02-28

Oh, its just a typo, you should follow the 1.5M

BlackShArk666 (author)ASCAS2016-06-02

Actually, the schematic and PCB it is also a capacitor 100uF / 25V, and in the parts list there is not ;).

dtpit (author)2016-01-28

can I use it as guitar amplifier

iulian.petre.79 (author)2015-05-21

I'm working at this project. After i'll finish, i will attach some necessary images.

MakerMan8 (author)2015-02-18

hi, just wondering if that's 2x30w RMS or peak?

yhdesai (author)2015-02-06

i have 2 speakers of my father's stereo system
i dont know its wattage

duchalski (author)2014-10-08

What is exact size of the PCB you used?

IT-Jack (author)2013-03-29

But do you know any international sites, where people like me can buy amp chips and so on?

ASCAS (author)IT-Jack2013-03-29

If your looking for robotic parts, go to , If you are living in america radioshack is a popular electronic store (although has incomplete retail products). If you want anything related about speakers and amps .

IT-Jack (author)2013-03-28

So where do you buy amp chips and all the other things you need too build a amp?

ASCAS (author)IT-Jack2013-03-28

Luckily, most of the parts are available in local electronics stores here in the Philippines (such as: Deeco, E-gizmo, Alexan, RAON), they're cheap too! From Resistors, Capacitors, Transistors, I.C.s to Heatsinks, they serve a variety of products even kits. Everything that you imagine can be bought here in our country. Since we are near the manufacturing countries such as Taiwan, China, Japan, Singapore, Philippines (our country) everything on the pricelist is cheap!

IT-Jack (author)2013-03-25

What does the hole project cost, maybe you have guide to how you build it step by step?

ASCAS (author)IT-Jack2013-03-25

It costs less than P1,000.00 ($20). I actually had an incomplete documentation with this project of mine, I will have to make another one of these again to take a full cover of the DIY amp.

IT-Jack (author)2013-03-24

thank very nice, but don't you have a list of all the materials?

ASCAS (author)IT-Jack2013-03-25

It's stated from the image above, it's a bit small :)))

tdaly2 (author)2013-01-06

please do another soon plus instuctable. i have seen your gainclone power amp but i wanna c a similar amp with volume control much like this. :)

ASCAS (author)tdaly22013-01-07

If you are planning to build an amplifier with a volume control, you could just add a pontentiometer, the left end of it should be connected to the input, the center should be connected to your output (amplifier-input), and the right end should be connected to your common ground.

tdaly2 (author)2013-01-06

also im a bit of a noob but to get speakers going could you just use a preamp or what sort of amp/ amp combos do you need minimal to get speakers going with volume control and aux input?

iApple guy (author)2012-10-27

Was that the one that I recommended?

ASCAS (author)iApple guy2012-10-28

Not sure. But a lot of people were asking about the amplifier I used inside my Portable Boombox (instructable)​ so I ended up posting this because it has the same amplifier inside it.

profpat (author)2012-10-27

great project! hope you could post more!

ajoyraman (author)2012-10-27

Nice Work !

I could not make out if you have used co-axial shielded cables for the signal input. In my experience this is very important to keep down hum and cross-talk.

Enjoy good music.

ASCAS (author)ajoyraman2012-10-27


You're right indeed, I was going to use a shielded coaxial cable for good grounding, although the whole enclosure was made-up of plastic so there are no good ground connections. I have a great experience with "TDA" amps because, I noticed that they added a noise reduction feature to some TDA chips, so when there's no input connected, the amplifier is completely noiseless.

brendan945 (author)2012-10-27

Please please go back and do a full step by step!

cdaigle (author)2012-10-27

I really look forward to seeing a step by step. I have been thinking about buying an objective2 kit.

About This Instructable




Bio: Hi I'm Angelo! I am a 18 y/o college sophomore taking my majors in BS-ECE at the DLSU. I use my course as ... More »
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