Recently, I salvaged some Sony mini component system. Removed r-core transformer and discarded the remainings. I'm about to trash speakers, then I realize each speaker enclosure has a pcb inside. I removed them and checked, they are TDA2050 based amp boards;
This is the schematic for mini system power supply part. Looks like only thing I'm missing is -12v for relay drive.
And this is the schematic for tda2050 pcbs.
My question is; can I use salvaged transformer to power up these amps? I can feed external -12v to operate relay. I'm just curious.
Or is it a waste of time? 🙂
This is the schematic for mini system power supply part. Looks like only thing I'm missing is -12v for relay drive.
And this is the schematic for tda2050 pcbs.
My question is; can I use salvaged transformer to power up these amps? I can feed external -12v to operate relay. I'm just curious.
Or is it a waste of time? 🙂
Thanks. Should I expect a decent sound? Or rubbish?
I used class D amps such as ta2021,tpa3116 before.. Looks like this tda2050 is somewhat ancient? Am I correct?
I used class D amps such as ta2021,tpa3116 before.. Looks like this tda2050 is somewhat ancient? Am I correct?
The TDA2050 are fine chips, better than those Class D ICs. Look at the TPA3116 that has an odd distortion curve peaking up where your hearing is most sensitive at about .2-.5%THD. Most analog amps deliver lowest distortion in that range.
JonSnell, are you thinking of of the TDA2003? The 2050 was not intended for automotive use. The TDA2050 would need an auxiliary power supply for its rails
JonSnell, are you thinking of of the TDA2003? The 2050 was not intended for automotive use. The TDA2050 would need an auxiliary power supply for its rails
Actualy TDA2050 Works as low as 9V (+-4.5V) I am succesfully using it with 12V battery in portable speaker. It is driving 1.3Ohm load without problems.
John, what kind of sound should I expect? Is it ok or rubbish?
What do you think about amp design-schematic?
What do you think about amp design-schematic?
Although you not asking me, but i can tell you that sound quality very comparable with LM chips. It's even pin compatible with LM1875. So you probably could even solder some LM1875 in, but a few parts needs to be changed then. But TDA2050 is really Hi-Fi by itself, so theres not much point in changing.
One more thing. I see that supply elctrolytic capacitors are really small. I would change them for biger. Looks like there is some space for bigger ones.
I think, i would just remove chips and make nice simple pcbs. Because those have a lot of not needed things.
One more thing. I see that supply elctrolytic capacitors are really small. I would change them for biger. Looks like there is some space for bigger ones.
I think, i would just remove chips and make nice simple pcbs. Because those have a lot of not needed things.
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Valtra, you're right, supply caps are 2200uf.
First, I'll try these boards as it is. Can you suggest me a good design or schematic?
First, I'll try these boards as it is. Can you suggest me a good design or schematic?
I'm using some other chips intended for car use in a couple projects right now, and have been very impressed with the performance so far.
I have a stash of some nicer(film/foil)capacitors that were surplus, older parts and have been replacing anything that touches the signal.
You may be able to remove the input coupling capacitor if that particular module will tolerate it; one of mine has so far, the other has been replaced by a decent film cap. Keep in mind that the values for the input caps are assigned in the datashett assuming an electrolytic, if you use a film, the value can be much smaller(.22 uf).
These amps have poor pssr, but if you do some basic line conditioning on the primary side of the transformer, they can really sing, along with the other mods.
I have a stash of some nicer(film/foil)capacitors that were surplus, older parts and have been replacing anything that touches the signal.
You may be able to remove the input coupling capacitor if that particular module will tolerate it; one of mine has so far, the other has been replaced by a decent film cap. Keep in mind that the values for the input caps are assigned in the datashett assuming an electrolytic, if you use a film, the value can be much smaller(.22 uf).
These amps have poor pssr, but if you do some basic line conditioning on the primary side of the transformer, they can really sing, along with the other mods.
Thanks for the replies. As I see these tda2050 amps are driven by njm4558. Whenever a component that I have sounds awful, I always found 4558 in the signal paths. Let's see how will they sound first, then I'll play with the chips as you guys suggested.
I believe that sound quality will be better without njm4558 😀
I don't get why they used at all. TDA2050 is all you need.
The 4558 seems to be a slightly improved dual 741. Not the greatest slew rate or noise figure. If you look at the OP's schematics, the second amp is getting some signal from negative terminal of the speaker before it is returned to ground through a .22 ohm resistor. This arrangement can certainly affect the sound.
Yep; the 4558 along with the 741 certainly do put the word "bog" into the phrase "bog standard".......
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