LM 383 help

[hobbyguy]

Hi, I when to my electronic store and ask for the LM383 but they didn't have it so they told me that the TDA 2002 is the same thing so I have that using instead of the LM383.

So I build the 7Watts amp with this TDA 2002 but the thing I'm having trouble is that with two nine volts battery it just makes a weird sound but with the one 9V I could hear it, and pretty loud too, but it doesn't sound clear I would describe it as distorted, and I was told that this amp could be power 5 to 20V so if you could tell me whats going on to be able to hear it rite and clear. Well thank you and for any comment.

[gootee]

DATASHEET:
http://www.st.com/internet/com/TECHN...CD00000123.pdf

Note that 18V is the "absolute maximum" operating voltage.

Apparently you have not quite used the recommended circuit.

Also, what was your load impedance? They show only 4 Ohms and lower.

And how long would your nine-volt batteries last, putting out nine watts or so into 4 Ohms? That would be 1.5 AMPS of output current (and maybe around 2 AMPS of input current).

What sort of heat-sink did you use, for the chip?

[hobbyguy]

Originally Posted by gootee

DATASHEET:
http://www.st.com/internet/com/TECHN...CD00000123.pdf

Note that 18V is the "absolute maximum" operating voltage.

Apparently you have not quite used the recommended circuit.

Also, what was your load impedance? They show only 4 Ohms and lower.

And how long would your nine-volt batteries last, putting out nine watts or so into 4 Ohms? That would be 1.5 AMPS of output current (and maybe around 2 AMPS of input current).

What sort of heat-sink did you use, for the chip?

The PDF link that you provide was TDA2003 are they the same.
and about the impedance, your talking about the speaker correct. Well the were some sony bookshelf speaker.
And I was told that I could power this amp with two 9V battery but they also told me that they weren't gonna last long, but I didn't leave them on for a long time but I had them on for a good 5min cause they didn't sound clear with the one 9V battery.

[madtecchy]

Small 9 Volt battery and loud = distortion.

regards Ian

[AndrewT]

Does the TDA2002 allow DC blocking of either or both +IN and -IN?
Is the chip internally configured to supply it's own input bias currents?

[gootee]

Originally Posted by hobbyguy

The PDF link that you provide was TDA2003 are they the same.
and about the impedance, your talking about the speaker correct. Well the were some sony bookshelf speaker.
And I was told that I could power this amp with two 9V battery but they also told me that they weren't gonna last long, but I didn't leave them on for a long time but I had them on for a good 5min cause they didn't sound clear with the one 9V battery.

There's this new thing they have, called "Google.com". You can type things in, there, and it searches the internet for them and then gives you links to click on to see what's at each of the resulting web pages.

The only thing that ruins it and makes it almost totally useless is that then you have to actually READ to find out what you wanted to know. (It's almost as ridiculous as thinking about actually pulling a bookshelf speaker off of the shelf to look on the back to see how many Ohms the impedance rating is, or looking up the specs on the internet.)

TDA2002 datasheet and application note, data sheet, circuit, pdf, cross reference, pinout | Datasheet Archive

http://www.national.com/ds/LM/LM383.pdf

HINT: For less than the price of a nine-volt battery, you could go to a few garage sales and buy four or five used "wall-wart" DC power supplies. If you can find a couple of 12V-15V ones that can put out a couple of amperes each, you could power some more-interesting chipamps. And I'm sure that you could find some 9-volt ones. You can usually connect the positive of one and the negative of another one to make a ground and then you have both + and - voltages from the two remaining wires.

[gootee]

Mouser Electronics - Electronic Component Distributor DC Adapter

http://www.mouser.com/Test-Measureme...e&Ns=Pricing|0

http://www.ebay.com/sch/i.html?_nkw=....c0.m270.l1313

Or maybe your next project should be building a couple of variable-output DC power supplies, or a dual variable output DC power supply.

[gootee]

http://www.ebay.com/itm/Vintage-Heat...92689723620907

http://www.ebay.com/itm/Lambda-LPD-4...item336e1e38d0

http://www.ebay.com/sch/i.html?_from...C+power+supply

Or get two of these and a dual-secondary transformer:

http://www.ebay.com/itm/Regulator-Po...item1e58da181c

[sofaspud]

Ahhh... one more opportunity to slip in another sofaspud platitude.
People who don't make mistakes don't make anything at all.
hobbyguy, is that a Fairchild part you have there? I have the datasheet for the TDA2002.
The circuit you show is the single-supply version. gootee is correct that 18V is the max operating voltage, but mostly wrong in making a federal case out of speaker impedance. I'd bet my paycheck that your bookshelf speakers are 4 to 16 ohms and therefore of little to no consequence in the grand scheme. madtecchy is mostly correct in that a 9V battery will not cut it as a power source for your amp. Surely you have a 12VDC wall wart around your place? That's what I suggest you use, at least at this stage of testing/troubleshooting.
And salesmen generally aren't known for being pillars of integrity when they want to make the sale. I'm ignoring all that "they said" stuff.
Anyway, let's compare what we have now to work with and go from there.
Here's the typical app circuit from the datasheet:

[sofaspud]

Looked over both schematics above and everything seems to check out. Yours doesn't include the output zobel network (C5 & R3 in the datasheet circuit), but I wouldn't think it is a necessity at this point. Probably a good idea to include it though if you have the parts handy. I also see you have a gain of 100. That might be a bit much, depending on your signal source - you can decrease the gain by increasing the 2.2 ohm resistor to 4.7. That makes the gain 47, which should easily allow an input of something like 100mV or more.
BTW, ignore the dashed-line components for now. They just tweak the frequency response.