Micro Bass Heads, why doesn't everyone use them?

[aborgman]

And "data" is what?

Information.

Data is data whether it exists as a discrete magnetic state on a disc or a penciled tic mark on a sheet of paper.

Correct - but a class-D amplifier pulse train IS NOT DISCRETE.

It's voltage level is discrete - but it's pulse width is analog... and pulse width is what is encoding the data.

If you had a limited number of pulse widths (say the pulsewidth could be from 0-256 uS wide, in 1uS discrete steps) it would be digital. You could have a pulsewidth of 0,1,2, etc uS but not 1.275 uS.

...but in most class-D amps the pulsewidth can take on an infinite (non-discrete) set of values. It CAN be 1.2785678uS wide. It's an analog signal.

If there aren't a discrete number of states, it ain't digital.

Once again, class D uses MOSFET binary switches with discrete on and off states. By definition that is digital.

No, it isn't.

It uses discrete on/off states - but it doesn't keep it on or off for discrete values of time.

Just because a class D amp facilitates pulse width values instead of digital data flow, does not mean it is not digital in function.

Correct.

If there are a discrete number of possible pulse widths - it IS digital... and there ARE class-D amplifiers built this way, although a tiny minority.

If there are an infinite number of possible pulse widths - it isn't digital... because the data is encoded in time, not voltage - and the encoding scheme IS NOT DISCRETE.

It is because of this digital state of functioning (rather than facilitating digital data flow) that blurs the lines between analog/digital conversion.

Most class-D amps don't do an A/D conversion. It's a really inefficient way to generate a PWM stream.

This is a good thing as digital technology evolves to more perfectly represent the pure analog nature of a vibrating bass string.

A pulse train run through a low pass filter is purely analog - or at least as purely analog as something can be.

 

[DJ Bebop]

...and can someone enplane what I am using, Carvin BX1500?

 

[seamonkey]

Well, some are - but the great majority aren't. There are a few designs out there that have a discrete number of potential pulse widths.

Yes you can have that
The Truth About Digital (Class D) Amplifiers — Reviews and News from Audioholics

AFAIK, No Bass amps, or power amplifiers used in MI industry are digital.

Even TC, it may be digital preamp but the power amp isn't.
In any case, the signal out of the amp going to the speakers is not digital.

I don't think there a chance anymore to hear or see any media that hasn't gone through the digital domain.

 

[NoFretsNoWorry]

Correct - but a class-D amplifier pulse train IS NOT DISCRETE.

It's voltage level is discrete - but it's pulse width is analog... and pulse width is what is encoding the data.

If there aren't a discrete number of states, it ain't digital.

It uses discrete on/off states - but it doesn't keep it on or off for discrete values of time.

If there are an infinite number of possible pulse widths - it isn't digital... because the data is encoded in time, not voltage - and the encoding scheme IS NOT DISCRETE.

Discrete on/off states do imply a digital-like function.

Class-D amplifier - Wikipedia, the free encyclopedia

As I have posted in past, we are addressing "digital-like" characteristics in switch function, not flow of data or pulse width. I have also said class D blurs the lines of analog/digital, not in conversion but function.

That function being switches being either on or off.

Class A amps are a better analog (continuous) representation IMO. They capture a more complete analog representation of waveform.

Electronic amplifier - Wikipedia, the free encyclopedia

If you could hold something truly "digital" in your hand, what would it look like?

In mathematics, numbers are tools of logic and scientifically applied human intellect to interpret the world.

Something being "digital" is a real as holding a fraction, a square root, or irrational number in your palm.

All I am saying is that anything digital (discrete units) is an intellectual way to interpret an analog (continuous) world.

And ironically, at a quantum level, neither the digital nor analog states exist!

Philosophically we are dealing with perception and our best human ways to interpret it. The digital world is merely a tool for dealing with the huge continuous world of analog. Albeit a far from perfect tool.

PEACE

 

[aborgman]

Discrete on/off states do imply a digital-like function.

No, they don't.

If those discrete on/off states don't force the data into discrete buckets - it ain't digital.

As I have posted in past, we are addressing "digital-like" characteristics in switch function, not flow of data or pulse width. I have also said class D blurs the lines of analog/digital, not in conversion but function.

No, it really doesn't.

The data is not encoded in a discrete manner.

That function being switches being either on or off.

...but for an analog amount of time.

All I am saying is that anything digital (discrete units) is an intellectual way to interpret an analog (continuous) world.

You are aware that our senses function in a much more discrete than analog manner?

And ironically, at a quantum level, neither the digital nor analog states exist!

Nope... at the quantum level ONLY digital states exist. Thanks Heisenberg.

 

[Dave W]

I like how you keep using Wikipedia as a source. Although a great source of information, it's still the internet.

 

[NoFretsNoWorry]

No, they don't.

If those discrete on/off states don't force the data into discrete buckets - it ain't digital.

Switch = on is discrete. Switch = off is discrete.

What flows as a result of either a switch being on or off is irrelevant. Discrete binary switches on or off = digital.

Answer this: On a vibrating bass string (kinetic energy engaged), what switch-like states are on or off? (I am not referring to nodes of constructive/destructive wave interference either; tone persists)

Then how can an amp with discrete states of on and off binary switches faithfully reproduce the continuous waveform of a bass string? Especially compared to class A amps?

Nope... at the quantum level ONLY digital states exist. Thanks Heisenberg.

Heisenberg perfectly addresses this issue with his uncertainty principle addressing electron states as either/or both particulate or wave-like! He asserted that the electron state of either wave or particle is difficult to determine....if I may paraphrase off the cuff.

A good Heisenberg comparison for the class D grey area I refer to, would be comparing the analog and digital phases of "reality". Which is which? When does one become analog, and when does one become digital? When is an electron particulate and when is it wave-like?

These are excellent points you share and I appreciate your spirited debate aborgman!

My disclaimer: I am capable of being fully and freely wrong at any time. I want to learn from it.

PEACE

 

[kittyboy]

NoFrets, we've all held beliefs and opinions that we later found out to be mistaken. It happens to *everybody*, so there's no shame in having posted something that was incorrect...

But there comes a time to say "Huh, I guess I was wrong about that" and let it go. It might sting a little, but then you can move forward in your research with a foundation of accuracy.

Peace.

 

[mbelue]

NoFrets, we've all held beliefs and opinions that we later found out to be mistaken. It happens to *everybody*, so there's no shame in having posted something that was incorrect...

But there comes a time to say "Huh, I guess I was wrong about that" and let it go. It might sting a little, but then you can move forward in your research with a foundation of accuracy.

Peace.

+1

 

[R Baer]

...how can an amp with discrete states of on and off binary switches faithfully reproduce the continuous waveform of a bass string...

How does a CD recreate the sound of your bass?

 

[seamonkey]

there are audio forums full of this debate

Everybody is liking class-d, from FOH systems to hearing aids

Here's another common Pulse Width Modulated device

Replaces big auto-formers
New ones have digital control circuits but still mainly pulse width modulated.

 

[NoFretsNoWorry]

NoFrets, we've all held beliefs and opinions that we later found out to be mistaken. It happens to *everybody*, so there's no shame in having posted something that was incorrect...

But there comes a time to say "Huh, I guess I was wrong about that" and let it go. It might sting a little, but then you can move forward in your research with a foundation of accuracy.

Peace.

Mistaken? Wrong? Incorrect?

Interesting. I thought I was debating the analog/digital nature of class D amps....a difficult concept to have any rigid conclusions about.

If you feel I am mistaken or wrong, I would welcome your input presented in a considerate, logical and reasonable way.

But merely claiming something is wrong for the sake of flaming will be ignored.

PEACE

PS feel free to ignore my posts here if you do not want to participate in a respectful way.

 

[Febs]

How does a CD recreate the sound of your bass?

I am way out of my league technically in this thread, but am I right to guess that he should be focusing more on Nyquist Shannon, and less on Heisenberg?

 

[Geddyfleaharris]

I thought this thread was about how nice it was that micro amps were WAY lighter than tube or bigger SS amps.

I seem to have stumbled into a hybrid physics/electronic engineering class.

The 747 didn't even come close to grazing my scalp when it was going over!

Carry on.....

 

[randysmojo]

Digital-like function, and an anolog signal converted to digital are NOT the same thing!

 

[grendle]

is it sample rate or current limiting???

how many times per second does the SMPS refresh? is it fast enough to overcome the low frequency lost at near clipping or current limiting to avoid thermal shut-down???

Naah its not quite like that. I'm not sure what the different mfr's are using. I saw one where the output is switched at a 400 kHz rate which was some of the audiophile level stuff. The space inbeteeen the switch time is basically lost, but its fast enough that you don't here anything cutting out. Its also slow enough to where some small nuances get lost (very few). Think of it as connect the dots. As the switching frequency increases there are more dots to work with and the signal is more accurately amplified.

Telecom and military technology have been well into the Ghz for a few decades, and the military into the Thz range for quite a wile. Its different technology for different purposes but very easily adaptable. So I'm sure it wont be too long until instead of 400,000 dots we have 4,000,000 or 40,000,000, or 4,000,000,000 to work with. It still wont sound like a beautifully imperfect tube though

 

[onda'bass]

whatever...i will be buried with a heavy amp, probably a mesa....

 

[Dave W]

According to this thread, an old school rotary phone or a phonograph is digital.

 

[thumbs&fingers]

Anybody play the Glock Blue soul yet?

 

[grendle]

According to this thread, an old school rotary phone or a phonograph is digital.

Basically. Yes. It's the same thing just a micro processor does it faster.