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Author Topic: TDA2050 power amp problems  (Read 4196 times)

Fossilshark

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TDA2050 power amp problems
« on: May 14, 2016, 08:11:38 PM »
Hi! i'm new to the site and the world of building amplifier.
I successfully prototyped a J-FET pre-amplifier for my guitar amp I plan to use as my main rig.
for the power amp i'm trying to build a TDA2050 based circuit. i'm using the circuit from the datasheet and i'm using all the correct components, except when i power it i get no sound?

here's my theories for problems so far:
i have it set up on a breadboard just so i can get sound to see if the circuit works

i'm powering it with SLA batteries (temporarily) and the power supply I will build last, i'm only giving it 12v (I tried 24v with two in series to no avail) mostly because I know these are probably knock off chips from china and i'm afraid to run them at max voltage.

should I be using a different circuit? I only need a single channel and bare minimum for this project and i'm just trying to get sound from the amp at this point.

I've tried output from the pre-amp (also built a bit sketchy) and output music from my phone, both inputs are giving no output.

please let me know if i'm posting in the wrong place or you need more information. thanks!

https://www.google.com/search?q=tda2050+datasheet&safe=active&espv=2&biw=1366&bih=599&site=webhp&tbm=isch&imgil=b0ZqEWSkqFrIqM%253A%253B5kutd-s7Jh-HGM%253Bhttp%25253A%25252F%25252Fdiyaudioprojects.com%25252FChip%25252FDIY-TDA2050-Hi-Fi-Chip-Amplifier%25252F&source=iu&pf=m&fir=b0ZqEWSkqFrIqM%253A%252C5kutd-s7Jh-HGM%252C_&usg=__AbtnPTTWlS0d7cMYYK8WzkRtr78%3D&ved=0ahUKEwiS56Kl5drMAhXK24MKHS3EBeAQyjcIMg&ei=YL43V5K3Ecq3jwStiJeADg#imgrc=b0ZqEWSkqFrIqM%3A

Enzo

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Re: TDA2050 power amp problems
« Reply #1 on: May 14, 2016, 10:43:29 PM »
Did you reference V+ and V- to ground individually?  Or did you connect the V+ and V- to either end of a battery?  The V+ and V- are separate power supplies, not the two ends of one.

Fossilshark

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Re: TDA2050 power amp problems
« Reply #2 on: May 14, 2016, 10:45:22 PM »
i assumed a battery acted like a V+/V- supply. what would i have to do to make it that way?

incurably_optimistic

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Re: TDA2050 power amp problems
« Reply #3 on: May 15, 2016, 06:08:31 AM »
you can use two batteries: connect + end of first battery to the Vs+ point on the schematic, - of the first battery to the ground, + side of the second battery to the ground and - of the second battery to V-. That way you get a +-12V power supply and everything should work just fine.

Like this:

Fossilshark

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Re: TDA2050 power amp problems
« Reply #4 on: May 15, 2016, 05:36:48 PM »
Thanks alot! Ill try it out

Fossilshark

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Re: TDA2050 power amp problems
« Reply #5 on: May 15, 2016, 09:32:52 PM »
I tried connecting the - of one battery and the + of another to ground and using the other terminals as a +/- supply like in the picture but it seems to be shorting the chip?? The speaker is popping and the chip is heating up

J M Fahey

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Re: TDA2050 power amp problems
« Reply #6 on: May 16, 2016, 12:29:34 AM »
Then you'll have to triple check schematic against real world build.

You might have missed something.

A picture might help.

phatt

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Re: TDA2050 power amp problems
« Reply #7 on: May 16, 2016, 08:40:21 AM »
Agree,, either something is not connected that should be or something is connected that should not be.
It's very easy to miss wire a breadboard setup, especially when you are not familiar with electronics. 8|

If you are using batteries the Amp should be wired up like this picture and I'd be using a fuse on each supply rail. :-X  If the batteries are large they can dump a lot of current instantly which would blow the chip in a blink if something was wired up wrong. :'(

Follow the 3 colours and make sure they go to the right pins.

And Yes a close up picture of what you have on the bench will help speed up the process. :dbtu:
Phil.

Loudthud

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Re: TDA2050 power amp problems
« Reply #8 on: May 16, 2016, 04:27:36 PM »
The tab of the TDA2050 is connected to the negative supply pin so the package must be insulated from the heatsink.

Fossilshark

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Re: TDA2050 power amp problems
« Reply #9 on: May 16, 2016, 07:32:31 PM »
This is currently how i have it set up.

Pin 1: .1uf cap connected to the input and 22k resistor going to ground

Pin 2: 22k feedback resistor to pin 4 and 6.8k resistor going to 10uf cap to ground

Pin 3: just v- wire

Pin 4: 2.2 ohm resistor to .47uf cap to ground and speaker output

Pin5: just v+ wire

Chip seems to be shorting when i try to do the v+/v- supply trick with the batteries. Could it be a grounding issue? I have the breadboard grounded to the benchtop power supply i built but i dont know if thats actually connecting it to ground.
« Last Edit: May 16, 2016, 07:35:21 PM by Fossilshark »

J M Fahey

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Re: TDA2050 power amp problems
« Reply #10 on: May 16, 2016, 09:15:51 PM »
Please draw a schematic of what you actually built, even if in cheesy Paintshop, we do not rate artistic skills here.
Top it with a nice picture showing actual construction.

This is a simple circuit which "should" work.

That said, you might have already killed the chip because of some earlier misconnection  :(

Fossilshark

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Re: TDA2050 power amp problems
« Reply #11 on: May 16, 2016, 11:12:27 PM »
The exact datasheet schematic is what i seem to have built (obviously not somwhere). I bought 20 chips im not that worried about them blowing lol. I apologize for the photography. The green wire is v+ and the blue wire is v- (ran out of red and black recently) the red wire is going to an 8 ohm speaker and the yellow wires are just jumper cables.

phatt

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Re: TDA2050 power amp problems
« Reply #12 on: May 17, 2016, 12:09:02 AM »
Arrhh No !!!
Lesson one,,, NEVER Run these chips without a heat sink. :trouble :trouble :trouble
As Mr Fahey Has already noted, the chip is likely already fried but as you have many it's a lesson for you. :tu:

Can't quite make out the wiring but the heat sink is your first fix up job.
Phil.

exztinct01

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Re: TDA2050 power amp problems
« Reply #13 on: May 17, 2016, 01:02:26 AM »
I thought those tda's have long been gone and out of production? Where could they still be located?
~ Stephen

Fossilshark

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Re: TDA2050 power amp problems
« Reply #14 on: May 17, 2016, 07:46:32 AM »
Even if im just trying to get sound out of it as a test i need a heatsink? And the question about production, im pretty sure these are knockoffs from china i ordered them at amazon.

 

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