TDA2050 Bridge Amp

K10ur

Member
2020-02-29 2:28 am
Hello everyone. I want to build an amp to drive a 20" 4ohm 150w max subwoofer in a car. I'm planing to use boostor project to boost supply voltage from 12v to +-22v. I'm looking for an ic amp to deliver 70w-100w from said supply.



I've found the schematic below using TDA2050's in a bridge configuration claiming to output over 70w which is enough for me but TDA2050 is obsolete and i'm concerned fakes won't be able to handle +-22v supply voltage. Even if its a TDA2040 rebranded as 2050 it should fry according to datasheets.
b1f591d33b9345a582ad1e7d0456535a.jpg


What experience do you have on fake 2050 chips? Is it worth the shot? I'm open to new ic suggestions. Or maybe should i go with transistor amps? Any idea or recommendation is welcome. Thanks for reading.
 

Sangram

Moderator
Paid Member
2002-09-25 11:01 am
India
There is no easily available Class AB chip that will handle a 4 ohm subwoofer at 22V rails in bridged mode. You will need a minimum of 4 chips, in PBTL configuration, or a 'booster' type circuit with 1 chip per half - which might actually be unstable.

Most Class D amps should also be able to handle it, but most are single supply or need higher rails.
 
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Have you considered using class-D ? A TI TPA3255 can drive 2 ohms in mono mode to 600 Watts on a 50V supply.
It costs less than $11 in single lot from DigiKey and is not much bigger than a postage stamp and does not need a
huge heatsink due to the high efficiency. Seems like just the ticket for a sub in a car.

The higher efficiency lowers fuel usage and your carbon footprint and reduces climate change. OK that's probably BS.

 
With a +/-22V supply and a 4 Ohm speaker, LM3886 is your only chance without having to connect more ICs or channels in parallel. As stratus46 recommends, a class D amplifier seems more suited because you need quite some power, heating of the amplifier will be an annoyance and you only use it for low frequencies.
There are divided opinions on if class AB or class D sounds best from the mid-range and up. If it is about getting some bass-kick, I guess most agree that class D is it.
 

K10ur

Member
2020-02-29 2:28 am
Thanks and cheers to you all!


That schematic will work into 8 ohms, but a 4 ohm speaker will overload the amplifier chips.

I would suggest something like a TDA7294 board with an appropriate split power supply, or perhaps one of the many class D boards now on the market.


I did experiment with this circuit before and it fried after seconds under these conditions :) But why is that? What info on datasheet should point that out?


TDA7294 seems good, claims about 60w a bit under my goal but still seems like my best choice for now.

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There is no easily available Class AB chip that will handle a 4 ohm subwoofer at 22V rails in bridged mode. You will need a minimum of 4 chips, in PBTL configuration, or a 'booster' type circuit with 1 chip per half - which might actually be unstable.

Most Class D amps should also be able to handle it, but most are single supply or need higher rails.


If its 4 cheap chips i might actually spend the time to do it, so what chips are we talking about? For example can i use TDA2040? Connecting outputs of amps together sounds risky, wouldn't i need to balance them somehow?

For example what do you think about this circuit? More transparency in active speakers - part II - diyAudio

Do yo think this can supply significantly more power than TDA7294 so it's worth the complexity?


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Have you considered using class-D ? A TI TPA3255 can drive 2 ohms in mono mode to 600 Watts on a 50V supply.
It costs less than $11 in single lot from DigiKey and is not much bigger than a postage stamp and does not need a
huge heatsink due to the high efficiency. Seems like just the ticket for a sub in a car.

The higher efficiency lowers fuel usage and your carbon footprint and reduces climate change. OK that's probably BS.



I liked TDA3255 but unfortunately it's not locally available and my only option is AliExpress to source that ic right now. But class-D sounds interesting, is there any other ics you can recommend? Maybe i'll get lucky and find them locally? 600w is overkill for me 150w is speakers max. And as long as its working stable i don't think mother nature would care for my sound system of all things:). It's cool to have a cool amp though:cool:.
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With a +/-22V supply and a 4 Ohm speaker, LM3886 is your only chance without having to connect more ICs or channels in parallel. As stratus46 recommends, a class D amplifier seems more suited because you need quite some power, heating of the amplifier will be an annoyance and you only use it for low frequencies.
There are divided opinions on if class AB or class D sounds best from the mid-range and up. If it is about getting some bass-kick, I guess most agree that class D is it.


LM3886 is locally available for a reasonable price and seems like a good choice, only its output power rating falls around 40w which is low for my target but seems like the simplest way to drive my sub. Class-D also sounds like a good solution. Can you recommend any particular chip or board?
 

K10ur

Member
2020-02-29 2:28 am
......................................................
LM3886 is locally available for a reasonable price and seems like a good choice, only its output power rating falls around 40w which is low for my target but seems like the simplest way to drive my sub. Class-D also sounds like a good solution. Can you recommend any particular chip or board?


The LM3886 datasheet promises 68W in 4 Ohm. That should easily be possible.
For class D, I can suggest "IRS2092S", "TPA3255" or "TDA7498E" based amplifiers.
 
Also what do you think about something like this, do you think it would work?
Power Amp Super Bridge 120W by IC TDA2030 | Hypsine Electronics
and
200 Watts Power Amplifier With TDA2030 pinout and connection diagram - Schematic Circuits Elektropage - The Electronic Source

I'm also looking for 100w ish class-D if anyone ran recommend any circuit.
Thanks


[IMGDEAD]https://www.eleccircuit.com/wp-content/uploads/2009/08/power-amp-super-bridge-120w-by-ic-tda2030.jpg[/IMGDEAD]


For the schematic you show there seems to be a major flaw at the input of IC2 ("+"-input to ground, "-"-input to positive supply rail).
 
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Actually the thing is full of drafting mistakes. I am pretty sure the booster transistors would need some connection to the load as well.

I can only guess that the schematic may have been redrawn by someone who either didn't have a clue how it was supposed to work or didn't care at all, or even deliberately obfuscated.

That's the kind of quality you get on random free schematic websites.
 

K10ur

Member
2020-02-29 2:28 am
For the schematic you show there seems to be a major flaw at the input of IC2 ("+"-input to ground, "-"-input to positive supply rail).


Actually the thing is full of drafting mistakes. I am pretty sure the booster transistors would need some connection to the load as well.

I can only guess that the schematic may have been redrawn by someone who either didn't have a clue how it was supposed to work or didn't care at all, or even deliberately obfuscated.

That's the kind of quality you get on random free schematic websites.


Yes, sorry about that, i noticed something wrong with that color schematic after posting but forgot to mention. Original circuit is in the other link and seems ok to me afaik, what do you think about that one?



Here it is:
200watts_power_amplifier_tda2030_e49.jpg




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The LM3886 datasheet promises 68W in 4 Ohm. That should easily be possible.
For class D, I can suggest "IRS2092S", "TPA3255" or "TDA7498E" based amplifiers.


LM3886 promises that at +-28, i have +-21 only and power reduces to around 40w at that supply voltage. I will look into those class D's thanks a lot for recomendations.
 
I will go with class AB i think bc no class D amp ic is easily available for me, and solid state class-D's are too complex to deal with for this project. So what chips can i bridge to achive 70w or more at +-22v supply?
Hi K10ur
the requested power depends on your speakers impedance. e.g. 8ohm speakers.
22V per rail is with strong/stable Power supply lets say about 19Vpeak-this is the max swing of the output. its is then 19*0,707=Vrms--> 13,4Vrms --> bridged means 2 times this continuous voltage so 26,8V bridged
P = U^2 7 R = 26,8^2 / 8 = 89W.. so your target is full filled!!!


yes the LM3886 is a very good mono chip amp!

chris
 
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igniz

Member
2021-06-14 5:40 am
tda 2030

Yes, sorry about that, i noticed something wrong with that color schematic after posting but forgot to mention. Original circuit is in the other link and seems ok to me afaik, what do you think about that one?



Here it is:



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LM3886 promises that at +-28, i have +-21 only and power reduces to around 40w at that supply voltage. I will look into those class D's thanks a lot for recomendations.
 

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igniz

Member
2021-06-14 5:40 am
Yes, sorry about that, i noticed something wrong with that color schematic after posting but forgot to mention. Original circuit is in the other link and seems ok to me afaik, what do you think about that one?



Here it is:



-------------------------





LM3886 promises that at +-28, i have +-21 only and power reduces to around 40w at that supply voltage. I will look into those class D's thanks a lot for recomendations.
Tda2030-with-transistor-amplifier-circuit-diagram.jpg