I've used one of these (came assembled with pot) to build stand alone spring reverb for my mixer return channel. I've just used L channel for input and R for output, volume on max. Nothing else. It turned out to be a perfect gain in/out, sounds just fine (for a spring reverb) and has very little noise compared to my previous transistor build. But that's only the application I did with these.
How good actually are these chips when it comes to audio quality? I think these could be handy for building lower gain preamps etc. But would the sound quality cut it for HiFi or even a studio project? Apparently these are digitally controlled so distortion is minimal, not that I understand how it actually works
Cost is near nothing.
This is what I used here
1-10 x PAM8403 5V 3W+3W Mini Audio Digital Amplifier Board with Volume Control G | eBay
How good actually are these chips when it comes to audio quality? I think these could be handy for building lower gain preamps etc. But would the sound quality cut it for HiFi or even a studio project? Apparently these are digitally controlled so distortion is minimal, not that I understand how it actually works
Cost is near nothing.
This is what I used here
1-10 x PAM8403 5V 3W+3W Mini Audio Digital Amplifier Board with Volume Control G | eBay
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Why would you use a class-D power amplifier as a "lower gain preamp", instead of a plain old op-amp?
I'm not sure you really want (not to mention need) all that added EMI / RFI inside of a preamp. Or any line-level application, really.
And where/what exactly is "digitally controlled"?
The whole "the D in class-D stands for digital" is a bit of a misnomer.
Class-D amplifier - Wikipedia
Regarding spring reverbs, some guitar amps i've seen only used 1-4 opamps in parallel to drive the reverb tank, so no real "power" needed, i would think.
I'm not sure you really want (not to mention need) all that added EMI / RFI inside of a preamp. Or any line-level application, really.
And where/what exactly is "digitally controlled"?
The whole "the D in class-D stands for digital" is a bit of a misnomer.
Class-D amplifier - Wikipedia
Regarding spring reverbs, some guitar amps i've seen only used 1-4 opamps in parallel to drive the reverb tank, so no real "power" needed, i would think.
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My experiences with the PAM8403 as a (low) power amplifier are surprisingly good. On the output you have the audio signal but also the carrier higher-frequency signal. The carrier signal is in large removed by the speaker cables and the inertia of speaker drivers. That carrier signal I would not like in my pre-amplifier.
As a pre-amp, I would do like Khron and use a traditional pre-amp normally based on an OP-AMP. An OP-AMP will have significantly less distortion than a PAM8403.
As a pre-amp, I would do like Khron and use a traditional pre-amp normally based on an OP-AMP. An OP-AMP will have significantly less distortion than a PAM8403.
You are fully right, it works surprisingly well. It is most likely even "HiFi". Power amplifiers, in particular class D amplifiers, are constructed in a way to solve the task of driving speakers with good efficiency and low output impedance. A pre-amplifier is normally constructed to have low distortion, a reasonably high input impedance and a reasonably low output impedance. Therefore, using a power amplifier as a pre-amp or a pre-amp as a power amp (many OP-AMPs in parallel as an example) does normally not make much sense. Use them for what they are designed for, that's better.
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You might be confusing "gain" with (some form of) "power".
Usually, "gain" is used in the sense of voltage (amplitude) amplification.
While it's true that the chip does have a fixed-gain internal "preamp" (or rather, voltage gain stage), its main role is to provide a (relatively) high-current output, capable of driving a 4-8 ohm load.
Most line-level stages are not intended to drive loads quite so low - the vast majority of opamps are spec'd for minimum loads in the region of 2Kohm or so.
Usually, "gain" is used in the sense of voltage (amplitude) amplification.
While it's true that the chip does have a fixed-gain internal "preamp" (or rather, voltage gain stage), its main role is to provide a (relatively) high-current output, capable of driving a 4-8 ohm load.
Most line-level stages are not intended to drive loads quite so low - the vast majority of opamps are spec'd for minimum loads in the region of 2Kohm or so.
Considering that it's a class D amplifier running with no output filters, I wouldn't give them very high marks for sound quality. They might be ok with those cheap transistor radio speakers, but anything with a proper tweeter would probably reveal their shortcomings pretty quickly.
It is about the least powerful class D amplifier you can find. It is amazingly good for low power purposes. It is not worth considering for a guitar amp. Consider TPA3116/18 instead.
Check THIS out.
These aint yer ordinary little gummers ... they use power supply technology to amplify sound.
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