Help selecting an amplifier IC

This conversation is getting a bit audiophile, meaning the conversation doesn't make any more sense technically to me.

I've yet to hear any normal headphones that don't function with a LM386 or a mobile phone. I have listened to $200+ head- and ear-phones and they sound fine with a typical mobile phone.

If the THD is too high, you'll have to search for a design which has lower THD. It won't make the project very hi-fi anyway, because if you were interested in that, you would not be using the in-built analog output from the DSP.

Sounds like the project just changed from a DSP amplifier to an audiophile headphone amplifier project.. in which case there are online schematics of such amplifiers you could examine (there are audiophile websites with these schematics).

Sorry if I am being scrambled in my thoughts and reasoning. You do have a point that this won't be the highest fidelity. It is still a DSP project, but if I can find an IC that will be good enough for headphones with 300 ohms like the popular HD600 from Sennheiser then it will be suitable. I just want enough power to make those have enough volume and decent enough sound quality. I'm not saying the LM386 can't because I don't know, but if you're comparing it to a mobile phone then I would be concerned. If it can outperform a mobile phone and drive higher impedance headphones decently, then I can use it. I initially said I might not use it is because it is mono. My friend is making the PCB and soldering the components so he said he would prefer 2 channel/stereo IC. The LM4880 or LM4881 is something we are looking into because it is stereo, but we are still looking.

Edit: My friend told me that the DSP itself is .9Vrms or 2.5V peak to peak. So, I don't think I need as much power as I was expecting, right? He was saying that this level can drive earbuds and low impedance headphones, but we still want to add another amplifier to drive higher impedance headphones.

Hi Jimmy,

   Why don't you build a stereo amplifier using two LM386 on a prototyping board and test it with your headphone. If you are satisfied with the result then use it for the project.

It won't take much time to build one from scratch.

Regards,

Aswin

Hi Jimmy,

Here is a place you can buy a small stereo amplifier for $5 and they throw in two speakers to boot. These are the type of desk computer speaker I was referring to.

https://www.parts-express.com/sound-force-505-powered-computer-speaker-pair--319-122?gclid=CjwKCAjwtNf6BRAwEiwAkt6UQotU-_QwkVShUNMpFSfAN9QkOqIiNw_-40LGPmPPDoDPwX8FuWQ1qBoC45UQAvD_BwE

John

jimmy5893  wrote:

 

good enough for headphones with 300 ohms

That's unrealistic. You're asking for some high power stereo chip to drive up to 3W for one set of headphones because a mobile phone type amplifier isn't good enough, and now to drive high voltage high impedance too, with THD requirement better than typical single-chip headphone amplifiers. I think you may have to design a custom circuit, or just use normal headphones.

It can't be too hard to solder on a PCB

I'd recommend one of the chips from Maxim Integrated, MAX9716/9717, they can drive a mono speaker 1.4W at 4 ohms and 1W at 8 ohms.

They also feature headphone sensing.

It also comes in a 3x3mm uMax package.

Only managed to solder one on a breakout board.

The input for it is 2V-5.5V I think, which isn't that bad.

Is there a decent amplifier chip you would recommend?

3W is definitely too high of an expectation. I read that that the max power for the HD600 is less than .5W so that would be the maximum target at this point.

I heard that the LM386 is okay enough, but my friend wants a stereo IC so he doesn't have to solder two chips. Is there another option that comes to mind?

I haven't heard of maxim integrated so this is good, as I can look at another company now. Is there a stereo chip you can recommend?