An amplifier is more or less analogous to a variable frequency drive (VFD) in that they both work in much the same way = Input power is converted to DC and then back to AC with a different frequency. The main difference is that the control/drive signal for the power transistors in a VFD is generated internaly inside of the unit (although you can provide an external frequency reference signal) but in an amplifier this is provided from an external device like an audio source.
That's a very contrived way to explain what's called "power supply rejection ratio" or PSRR. An ideal amplifier circuit has an infinitely high PSRR, because for every unit of change in the power supply, the output does not change at all. Real amplification circuits (opamps, transistor amps, tube amps) have some finite amount of PSRR, which is the change in supply voltage divided by the change in output voltage. The amount of PSRR is also frequency dependant.
You are absolutely right. This is called "slightly" technical discussions though, where I do try to present academic concepts in a more practical and easy to understand way to people who are not so infatuated with theory ;)
@@slightlytechnical103 That's why I left out decibels and logarithms ;) Dividing some value by some other value is only slightly technical after all, right?
I think a good way of looking at is an amplifier is like a developing a photograph and the power supply is the photo paper you are printing onto. If the paper has any marks they will end up as part of the final image. Also if the paper has any contaminants the image might not adhere to it properly. If you want to develop a nice print you really are going to need high quality photo paper.
That explains a lot wrong with my set-up, thank you. Perhaps as a follow on some example of good vs bad ps at the bench, how to test for noise etc and also usb power. Keep up the great work!
Another analogy is comparing it to music. A bad power supply has the same effect on electronics as trying to record a music album on board a plane with a screaming baby in the background. The music will sound awful with the noise of the plane and the screaming baby, in the same way a bad power supply will add noise to a circuit and will cause issues in whatever it's attached to.
I like the analogy. I think people would appreciate you discussing the source of the noise i.e mains or line voltage so people what you described about filtering, transient response, and dampening for amplifiers results in better sound quality. Thank you.
Well the will be heard doesn't actually have to be that way with say a typical class ab amplifier. Unless you got it complerely maxed out to the rails the rails going up and down doesn't directly translate to anything in the output.
What I don’t like about this analogy is that it applies to absolutely everything in the natural world. It extends beyond power supplies to all matter or fields. The entire video could just be 5 second long and say “everything is a camera”. In a certain sense when I press my foot against the break peddle of a dang car my physical state, or rather the local environment around that peddle gets imprinted, transposed, and transferred like “camera” or “painting”. Seems like a good Art school thought exercise or project but not an effective way of communicating the subject at hand because it says nothing unique about the power supply.. OR I could be totally missing something here, not getting it, or maybe I’m just wrong about the analogy not being practically useful to others. This Like button and comment is a camera🤡
I will likely remember this analogy fron now on. Very good description
48 years in Electronics. My mantra: "A good Technician ALWAYS starts at the power supply."
An amplifier is more or less analogous to a variable frequency drive (VFD) in that they both work in much the same way = Input power is converted to DC and then back to AC with a different frequency. The main difference is that the control/drive signal for the power transistors in a VFD is generated internaly inside of the unit (although you can provide an external frequency reference signal) but in an amplifier this is provided from an external device like an audio source.
First time watching your channel. I appreciate your direct approach.
Thanks! Cheers :)
That imaging analogy was super helpful, thanks!
I'm an electronics novice, but the first transistor circuit I ever built made me think of the power supply in a very similar way.
That's a very contrived way to explain what's called "power supply rejection ratio" or PSRR. An ideal amplifier circuit has an infinitely high PSRR, because for every unit of change in the power supply, the output does not change at all. Real amplification circuits (opamps, transistor amps, tube amps) have some finite amount of PSRR, which is the change in supply voltage divided by the change in output voltage. The amount of PSRR is also frequency dependant.
You are absolutely right. This is called "slightly" technical discussions though, where I do try to present academic concepts in a more practical and easy to understand way to people who are not so infatuated with theory ;)
@@slightlytechnical103 That's why I left out decibels and logarithms ;) Dividing some value by some other value is only slightly technical after all, right?
I think a good way of looking at is an amplifier is like a developing a photograph and the power supply is the photo paper you are printing onto. If the paper has any marks they will end up as part of the final image. Also if the paper has any contaminants the image might not adhere to it properly. If you want to develop a nice print you really are going to need high quality photo paper.
Great analogy! Thanks!
That explains a lot wrong with my set-up, thank you.
Perhaps as a follow on some example of good vs bad ps at the bench, how to test for noise etc and also usb power. Keep up the great work!
@randombiopod7384 thanks for the comment. Yeah something like that is a good idea. I'll do that.
Another analogy is comparing it to music. A bad power supply has the same effect on electronics as trying to record a music album on board a plane with a screaming baby in the background. The music will sound awful with the noise of the plane and the screaming baby, in the same way a bad power supply will add noise to a circuit and will cause issues in whatever it's attached to.
I like the analogy. I think people would appreciate you discussing the source of the noise i.e mains or line voltage so people what you described about filtering, transient response, and dampening for amplifiers results in better sound quality. Thank you.
Yeah, I planned to go deeper into that definitely! Thanks!
Well the will be heard doesn't actually have to be that way with say a typical class ab amplifier. Unless you got it complerely maxed out to the rails the rails going up and down doesn't directly translate to anything in the output.
@lassikinnunen Yep, the push pull configuration helps with noise cancellation a lot. But it is not perfect for lots of reasons.
So you could also say the input signal is a tiny, clean canvas with a painting you are very proud of and want to reproduce bigger.
What I don’t like about this analogy is that it applies to absolutely everything in the natural world. It extends beyond power supplies to all matter or fields. The entire video could just be 5 second long and say “everything is a camera”.
In a certain sense when I press my foot against the break peddle of a dang car my physical state, or rather the local environment around that peddle gets imprinted, transposed, and transferred like “camera” or “painting”. Seems like a good Art school thought exercise or project but not an effective way of communicating the subject at hand because it says nothing unique about the power supply.. OR I could be totally missing something here, not getting it, or maybe I’m just wrong about the analogy not being practically useful to others. This Like button and comment is a camera🤡