I started my foray into diy audio tinckering with TDA2822 chip amps, then progressed, including a NAD 3020 saved from a skip, then an Onkyo and a TPA3116 based amp, but when my 3116 developed a fault, I went back to a PAM 8403 based amp that I had made earlier; and very nice it sounded to, so now I've made one based on a PAM 8406, and it's sound is quite remarkable. I'd say better than anything else that I've heard (not that I've heard much), especially the timbre of instruments.. But the thing is, WHY do I like the sound so much, they have terrible distortion.
So I have come up with the following possibilities -
I like the distortion
DNM amps have very little metal in their construction, something to do with eddy currents, is there something in this (there is very little metal in my current PAM amp)?
They have very low noise floor
They don't need so many amplification stages, meaning less distortion; but why can't this be measured if it's a different distortion to the one quoted?
They give a surprisingly good sound for what they are, just like a small speaker might give surprising bass for it's size, even though it might not be particularly good, the fact that is comes from a small speaker gives it a bias in it's favour.
There's some advantage in using a 5 volt supply instead of something like 40 volts duel rail, because there's less resistance in the circuit.
These are just some random guesses, I just can't get my head around an amp with such bad measured performance, sounding so good, if you have any ideas, or you think I must have cloth ears or something, please let me know.
So I have come up with the following possibilities -
I like the distortion
DNM amps have very little metal in their construction, something to do with eddy currents, is there something in this (there is very little metal in my current PAM amp)?
They have very low noise floor
They don't need so many amplification stages, meaning less distortion; but why can't this be measured if it's a different distortion to the one quoted?
They give a surprisingly good sound for what they are, just like a small speaker might give surprising bass for it's size, even though it might not be particularly good, the fact that is comes from a small speaker gives it a bias in it's favour.
There's some advantage in using a 5 volt supply instead of something like 40 volts duel rail, because there's less resistance in the circuit.
These are just some random guesses, I just can't get my head around an amp with such bad measured performance, sounding so good, if you have any ideas, or you think I must have cloth ears or something, please let me know.
- "very little metal in their construction"
- "very low noise floor"
- "don't need so many amplification stages"
Reasons based on physics;-)
"... an amp with such bad measured performance, sounding so good..."
Distinguish peek-measurement methods and hearing-measurement methods.
Peek measurement methods do not correspond to the complexity of hearing measurement methods, do not do justice to the perceptive capacity of the ear.
Have much much fun with these amps;-)
I like modest devices that just do their job with no special expense of time and money. It's not a competition and I'm not trying to impress anyone. I think people who build massive amplifiers for personal use are insane. Likewise, no esoteric equipment. There is no place in my house for a shrine to recorded music. I don't need to compensate for anything with my music system. Truth be told, mostly I listen to 2.1 computer speakers, because its convenient. I never turn it on just to listen to music. It's always while I'm busy with something else. It's like the car. It's an appliance that needs to function and waste as little of my time as possible. I could make a better amplifier than 99% of the world, but I have no use for it. What is better, anyway? I could afford "designer" things, but paying a lot of money for things makes me sad, not happy. Cost effective is what I like.
A small amp runs in its sweet spot of clarity and efficiency at low volumes...big amps lose clarity at low volume, and are sometimes power hungry.
Long term listening loss can also occur from too loud music.
I prefer to listen to a small amp, sourcing from a computer, quite clear enough.
Current one is a Philips, dual AN7125 chips, rated at 20W each, usual setting is about 1W...and it is very clear at low volumes.
Living room is uPC1238 (NEC), again in a Philips set.
At work, again Matsushita chips in a Philips amp, similar ratings.
Spare is a STK 4141 in a Kenwood, and a Sansui B1000, that is way over the top....120W/ch/8E IIRC.
Never used the Sansui, I do not have speakers that can cope with it....nor a big enough listening area.
Long term listening loss can also occur from too loud music.
I prefer to listen to a small amp, sourcing from a computer, quite clear enough.
Current one is a Philips, dual AN7125 chips, rated at 20W each, usual setting is about 1W...and it is very clear at low volumes.
Living room is uPC1238 (NEC), again in a Philips set.
At work, again Matsushita chips in a Philips amp, similar ratings.
Spare is a STK 4141 in a Kenwood, and a Sansui B1000, that is way over the top....120W/ch/8E IIRC.
Never used the Sansui, I do not have speakers that can cope with it....nor a big enough listening area.
Well, I think I pushed it a bit too far last night; some opening drum strikes on the beginning of Mars Volta pushed it into distortion, I backed of the volume a bit and all was well after that (still plenty loud enough), but it does show that it's quite close to it's limit' understandable considering what it is and what it cost. I'm hoping to finish some more efficient speakers soon, so it will be more in it's comfort zone. I just used an old radio for the mains transformer and case to see what the PAM 8406 can do: the black knob is the volume control.
What's happening with the power supply when you hear the distortion? Meter the supply voltage with your problem music program playing at normal full volume (preferably with an analog or needle type meter). It could just be a problem with the supply sagging under load, resulting in clipping and related problems rather than any fault of the amp, if it's just running out of steam and hence distorting on bass peaks, which is a typical sign.
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We wouldn't be playing with chipamps or hifi if we seriously wanted or needed "big" amplification. For personal or domestic applications "big" means a dinosaur design originating from 50+ years ago, in the times of excess when owning a 100WPC amp or driving a 1960's V8 gas-guzzler auto was cheap, dirty and simple. Soon though, the world will be limited to E-bikes, SUVs and tiny chipamps. So get used to it - welcome to the 21st century where there are only small speakers and multi-channel amps filled with increasing numbers of chipamps - just move to the correct forum here for chipamp discussion.
Its got a 4 farad super cap on the power rail, the PAM 8403 amp that I was using previously would work for a few minutes on 4 farad cap alone, but it is still possible that a peek would be so much higher than average that it saps the power.
Nope, apparently he's not fussy about classes but PAM8406 at least, happens to be class D with a twist in the form of a class AB output stage, according datasheets - something that should be posted in the Chipamp Forum anyway. https://www.diodes.com/assets/Datasheets/PAM8406.pdf
Some audiophiles agree that low powered amplifiers sound good. see the links below. From my point of view, lower powered amplifiers I have used have a better response, what was known in those days as 'slew rate' however this is a subjective view. Larger amplifiers sound a little dull. Sterile.
Simplicity may have something to do with it. After all, I have enjoyed the sound from an amplifier consisting of a single transistor. The lower powered amplifiers tend to have fewer components. See The Zen Amplifier by Nelson Pass
There is the phenomenon of low expectations.
Audio Files: Why Are Ultra-Low-Power Amps All the Rage Among Audiophiles?
High expectations for a low-power audiophile amplifier
There is also the view that 'you can hear things you can't measure'
According to the instructions that come with the circuit board, it has a de-fault class d mode, but it can be changed to class ab, which I haven't tried yet.
Being tight with money, I've saved a little, and a few years ago I thought about buying something flash, after looking at a few things I came to the conclusion that "bling" flash stuff wasn't bought for someone to enjoy, it was bought to insult the people who couldn't afford it. I've watch a house building program (grand designs) for many years, but now the houses they build are just huge, and some of the time it's not to show off how much money someone has, it's to show that they have TOO much money. I like high end audio, I like some of the big 1970s stuff, and Bang and Olufsen, I even considered buying some of the new Yamaha stuff (lovely looking amps and CD players), but it just seems over the top once you hear what a tiny PAM amp can do. I like the fact that there are expensive, high performance cars, they're almost kinetic, technical art, but I don't care if I have one or not, I'm happy riding a bike to work. Without a power meter on an old amp, I would have thought that I need hundreds of watts.
Ozi ozi ozi . It was sarcasm. Also class d dont like large capacitor bank for some reason. 4 f is too much. Also i had a 0.25w amplifier which drive 8inch speaker so loud you can almost hear it from other side of street. And i had a subwoofer 400w that is almost dead a you step out of the room.
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It's funny you should say that: much of the music we listen to is at low volumes, lo-fi. In the car, for example, if you want to have a conversation. At home if you want to talk. At a restaurant - I had the experience the other day of listening at 60 dB measured, it was good music but 60 dB is just too little. My amp at home can put out 70 dB at 1 metre and it is too loud for some people.