another try on OP2343, for audio amplifier

Excellent, Boki, but what happened to open up your writing floodgates? Usually your posts are a short sentence or two, or a sentence fragment!

As for your question, if I understand it correctly, the opa2343 cannot drive low-impedance loads without high distortion. It's only rated for well under 50mA output, and the specifications are for 10k loads, unless otherwise stated. Plots in the datasheet show rising closed-loop output impedance, and rapidly-increasing distortion for "low" load impedances as modest as 600 ohms. Changing to or adding an LM386 (note its minimum gain of 20x, so add an attenuator), etc., should help.

There was some speculation a while back that 'bokiteam' was actually a shared account used by a number of students, perhaps in a dorm context, perhaps working on class projects. If so, that would explain a certain cyclical nature in the complexity of the questions.

I have no idea whether it is true. But the same email alias has posted similarly-informed questions about computer programming and mathematics questions, in other newsgroups.

The OPA2343 is an *OP-AMP* Boki. It *isn't* a power amp. You need a *POWER AMP* to drive a speaker !

op-amps can provide up to several tens of mA to their loads. They aren't intended to drive low impedances. The load is usually in the kohms region

power amps can deliver much higher currents and therefore can work into low impedances like 8 ohms such as speakers.

See above. The OPA2343 ( and any op-amp ) won't drive a speaker ! It will simply distort at alow volume ( like you found ).

No.

LM386 isn't an op-amp !

Use a modern amplifier chip for Christ's sake ! If you would actually post the *full* info here about what you need it would even be possible to suggest a suitable one.

So you need 2 outputs that are independent. The 'AV' output will use the op-amp output and the speaker will use the power amp.

The requirement for the AV output to be unaffected by the level control.also means you can't use the DAC's internal volume control btw.

Also, why are you using a high grade Burr Brown op-amp for a rubbish mp3 quality player ?

Graham

I read in sci.electronics.design that Pooh Bear wrote (in ) about 'another try on OP2343, for audio amplifier', on Sun, 2 Oct 2005:

It puzzles me why anyone bothers to try to help this OP. He's always 100 m out of his depth, with a lead weight on each foot. And he doesn't take much notice of the advice people give him/her/it.

It isn't as if I haven't tried in the past, but after a while I began to wonder if it was me that was nutty.

It is indeed perplexing. He never seems to give up though. Maybe that's his redeeming feature ?

Graham

I read in sci.electronics.design that Pooh Bear wrote (in ) about 'another try on OP2343, for audio amplifier', on Sun, 2 Oct 2005:

They said that it couldn't be done. With a smile he went right to it, And he tackled that thing that 'couldn't be done', And couldn't do it.

Not mine, but I don't know who wrote it.

Why do you want to insist that I use some character set that you selected instead of leaving my browser settings alone?

Ted

Can you explain what you mean ?

I see plain text thus....

" Hi All, After the LM386 function work ( but still dealing with small noise problem), I have took another try about connect VR to OPA2343 directly( NO LM386 now) Why I do that is for save money, can I?

The OPA2343 is the original circuit that be connected after DAC(audio)

chip, I think why it here is for AV output spec, am I right? But the problem is I will hear the sound is distorted ( when I turn volume louder ) for 1W speaker,

Question:

1. The sound was distorted at a not louder enough volume, does the OPA2343 can't support that ? or this is speaker's problem?

1. If the problem is OPA2343, can I change OPA2343 to LM386 directly? and I will add one switch to switch mini speaker output or normal AV output, if this can be done and function work as previous circuit ( series LM386 after OPA2343 output), this will save a lot of money, is not it?

Short Description: The box has two audio output, one is the bundled mini speaker, antoher

is normal AV output ( I want this output will not be affected by volume controller (VR) of mini speaker ).

Best regards, Boki. "

What's your newsreader ? I assume you don't actually mean browser as such.

Graham

Ha... what's wrong with these texts ? I see them are normal here.

I use Google Groups (beta) to read news letters, and then reply directly, I think it is convenient, and this can sovle my news server connection problem.

so... I think my answer is Firefox, :-)

Which newsreader program should I use? I will try it soon. :-)

Best regards, Boki.

Sorry, I don't know what's the problem here...

Best regards, Boki.

works fine on freeagent

martin

It's *your* settings.

Set your newsgroup reader to us a specific font, rather than to accept the posters's font. e.g. In Mozilla THunderbird, click edit, newsgroup properties and in the resultant properties box, click "Apply default ..."

Ed

Have fun :)

A search for 'bokiteam' at groups.google.com is quite entertaining

Graham

any urls?

martin

Hi Win, Thanks, just keep moving. It seems that you think that is possible solve the noise problem when I chagen the opa2343 to LM386? it seems different to other's comment? how do you think?

Best regards, Boki.

I do? Who said anything about noise? What noise? Usenet noise?

Thunderbird should do then, it's the mail part of the mozilla suite.

I read in sci.electronics.design that Walter Harley wrote (in ) about 'another try on OP2343, for audio amplifier', on Sun, 2 Oct 2005:

It doesn't explain the incoherence of the articles; it isn't typical of people not being familiar with English, its' more like a form of dyslexia.