Class D popping up everywhere. Innovation?

[wcriley]

That might be a bit hyperbolic. Modern computers are only possible with high density vlsi circuits but they have some level of obsolescence that is accepted. We all know pcs dont last forever and when it breaks, buy a new one.

I don't think it's hyperbolic.
PCs and amps cost about the same.
Both have come a long way since the 50s.
Both are just tools that help us do the things we want to do.
Both are cheap and easy to replace when they break.

 

[bassman64]

I'm a little concerned.....and maybe I just don't fully understand.....but isn't a Class D power section digital?

I'd love tubes someday but I'm all for SS amps, on the condition that it stays Analog.

I'm not starting a Analog vs Digital debate...just wondering if others like me who have made up their mind in the Analog camp feel the same concerns/questions.

As far as my googling of it, seems like it works much like a ballast for a fluorescent lamp.

It seems pairing a tube preamp with a Class D power section, you're kind of defeating a purpose within your own amp.

Am I wrong? Is anybody else inclined to stay away from a Class D amp for these reasons? Can Class D be legitimately Analog?

I saw a bunch of the replies that debunk the digital situation of these new amps. Ill just say that there is something that I do not like about these types of amps. I cannot put my finger on it just something is just different than old tube amps of the 70's and the SS that came after them.

 

[JdoubleH]

I saw a bunch of the replies that debunk the digital situation of these new amps. Ill just say that there is something that I do not like about these types of amps. I cannot put my finger on it just something is just different than old tube amps of the 70's and the SS that came after them.

Sounds like fear of the unknown.

 

[bassman64]

Sounds like fear of the unknown.

no, thats not it. I had a PF 500 and a Mark bass Jeff Berlin amp and I just couldnt get a pleasing sound out of them. well, the PF had great sound just bad electrical issues. The MB just had a tone that I couldnt get past. damn shame because it is a well built amp.

 

[metron]

I don't think it's hyperbolic.
PCs and amps cost about the same.
Both have come a long way since the 50s.
Both are just tools that help us do the things we want to do.
Both are cheap and easy to replace when they break.

It is definitely hyperbole to suggest that someone who has a preference for amps that arent the most up to date designs would also prefer to use the original computer over a new one. Its also non-sequitur. Eniac could not perform modern computing needs such as typing words. The gap in capability of an old tube amp vs new 3 lb class d isnt even remotely on the same order. In some ways the old stuff outperforms new. Either way, if you prefer semi-disposable amps thats fine. I was trying to say that i do not.

 

[Oobly]

Technically, a class D amp has no digital circuitry, it's all analogue. However, the signal is converted to a pulse width modulated (PWM, which is BINARY, ie on/off) signal which then controls a switching circuit which acts as the amplifier.

The PWM signal is generated by a comparator which compares the input to signal to a high frequency triangular wave generator. The amplified signal usually has a low pass filter applied to it to filter out the high frequency components added by the PWM signal generation.

The quality of the output signal depends on the input signal frequency, triangular wave frequency, switching rate and low pass filter. High frequencies are the most susceptible to distortion in a class D, low frequencies can be reproduced more accurately.

So, you may be hearing some distortion of the higher frequencies in the case of the GB amp, but it may be some other factor of that particular amp that you didn't like.

 

[Ric Vice]

My favorite amp is a Walter Woods MI-400-8. At 9 lbs its heavy compared to the newer generation of micro amps. The only thing digital about the amp is the SMPS. I wish that I had had the money to buy the MI-600-8 when they were available.

Ric

 

[wcriley]

It is definitely hyperbole to suggest that someone who has a preference for amps that arent the most up to date designs would also prefer to use the original computer over a new one. Its also non-sequitur. Eniac could not perform modern computing needs such as typing words. The gap in capability of an old tube amp vs new 3 lb class d isnt even remotely on the same order. In some ways the old stuff outperforms new. Either way, if you prefer semi-disposable amps thats fine. I was trying to say that i do not.

Totally agree with the "preference" part. (Some of us like PCs; other prefer Macs.) What I was aiming at is the number of posts in these types of threads where the poster denigrates new technology just because it's "new" and "different".

Maybe it was hyperbole to use ENIAC as a comparison. A Commodore64 would have been a fairer comparison. My first gigging amp was a Bassman with a pair of 6L6 bottles and tube rectifier. Functional by the standards of the day (1970), just as the Commodore64 was in its day. Both are pretty much useless today except as conversation pieces.

Time and technology marches on. New doesn't always equal better, but...after "new" has matured and proven it's worth (as SMPS and Class D have begun to do), it's senseless to discount it just becasue it didn't exist 50 years ago.

 

[metron]

Totally agree! New amp technology is amazing. Hundreds of watts per lb is still crazy to me.

 

[JdoubleH]

no, thats not it. I had a PF 500 and a Mark bass Jeff Berlin amp and I just couldnt get a pleasing sound out of them. well, the PF had great sound just bad electrical issues. The MB just had a tone that I couldnt get past. damn shame because it is a well built amp.

Fair enough, I figured my assessment of your position might be an oversimplification. I meant no disrespect. I am unconvinced, however that the typology is the problem, and that an amp employing this one couldn't please you. I just don't think you've meet it yet.

 

[onosson]

Technically, a class D amp has no digital circuitry, it's all analogue. However, the signal is converted to a pulse width modulated (PWM, which is BINARY, ie on/off) signal which then controls a switching circuit which acts as the amplifier.

From Wikipedia.:

A digital system is a data technology that uses discrete (discontinuous) values. By contrast, non-digital (or analog) systems represent information using a continuous function. Although digital representations are discrete, the information represented can be either discrete, such as numbers and letters or continuous, such as sounds, images, and other measurements.

Isn't PWM, as you've described it, discrete or discontinuous? In what way is that not digital?

Edit: I own a MarkBass LittleMark Tube 800 (Class D) and love it!

 

[Bob Lee (QSC)]

Isn't PWM, as you've described it, discrete or discontinuous? In what way is that not digital?

It's only partially discontinuous. PWM translates the continuous varying values of signal voltage into continuous varying measures of time that define the pulse widths, and the switched voltage levels themselves have a continuous effect on the amplitude of the output signal.

 

[onosson]

It's only partially discontinuous. PWM translates the continuous varying values of signal voltage into continuous varying measures of time that define the pulse widths, and the switched voltage levels themselves have a continuous effect on the amplitude of the output signal.

That makes sense. Whenever I see people saying "Class D isn't digital" I've always wondered how exactly it wasn't... it seems to me that it's neither completely analog or completely digital, as part of the information is represented continuously and part of it is represented discretely. Does that sound right?

 

[seamonkey]

This answers a lot.
Invalid Link Removed
"All amplifiers are analogue, but some amplifiers are more analogue than others"

 

[onosson]

This answers a lot.
Invalid Link Removed
"All amplifiers are analogue, but some amplifiers are more analogue than others"

Thanks, interesting article! A lot of it is over my head, but I like the take on it.

Bottom line, a lot depends on your definitions! I always interpret "digital" as, fundamentally, "binary". So whenever information in a system passes through a state where some portion of the information is represented in a binary fashion, that to me is "digital".

For the authors of that paper, information that has any analogue component to it is still analogue.

I don't think either view is necessarily wrong, nor contradictory. Information can be BOTH analogue AND digital!

 

[seamonkey]

Grabbing chunks of stuff and making it continuous is not digital.
Water wheels grab discreet buckets of water and transfer that to rotation.
The movie screen analogy has also been mentioned.
Time itself may be stuttered.

If you replaced your bass guitar cable with a line-6 G50 would you suddenly say you have a digital system? The G50 is pure digital transmission. It's just part of the signal path.
In fact any music you listen to today has gone through digital and survived.
Nothing wrong with digital
Nothing wrong with Analog - that's how our ear drums work.
In our ears though a lot of little signals are sent to the brain through complex cell interactions.

 

[onosson]

Grabbing chunks of stuff and making it continuous is not digital.
Water wheels grab discreet buckets of water and transfer that to rotation.
The movie screen analogy has also been mentioned.
Time itself may be stuttered.

If you replaced your bass guitar cable with a line-6 G50 would you suddenly say you have a digital system? The G50 is pure digital transmission. It's just part of the signal path.
In fact any music you listen to today has gone through digital and survived.
Nothing wrong with digital
Nothing wrong with Analog - that's how our ear drums work.
In our ears though a lot of little signals are sent to the brain through complex cell interactions.

Exactly! Nothing wrong with digital at all - my entire music collection is hard-drive based, and I gig on keys on a Nord Electro.

I don't understand people who are driven to keeping things "pure" analogue as much as possible. It makes no difference to me - I just like to understand systems and terminology, which is what interests me in this discussion.

 

[Bob Lee (QSC)]

I think of "digital" as using inherently numeric or logical representation, which is different from just "binary," or more correctly dual-state.

For example, I think it's silly to think of a flashlight as digital simply because it has an on/off switch. It can be used in a digital system, though, if the light being on or off is used to represent some numeric or logical quantity or state, but that's an atypical usage.

 

[onosson]

I think of "digital" as using inherently numeric or logical representation, which is different from just "binary," or more correctly dual-state.

For example, I think it's silly to think of a flashlight as digital simply because it has an on/off switch. It can be used in a digital system, though, if the light being on or off is used to represent some numeric or logical quantity or state, but that's an atypical usage.

Right - it's representation of information that counts, not just whether something exists in one state or another.

Ultimately, I guess it's a false dichotomy to think of analogue versus digital.

 

[bassman64]

Fair enough, I figured my assessment of your position might be an oversimplification. I meant no disrespect. I am unconvinced, however that the typology is the problem, and that an amp employing this one couldn't please you. I just don't think you've meet it yet.

No offense taken...we are just chatting

I agree that I havent found the micro head that I am totally wow'ed over yet.

my Ideal rig would probably be an Ampeg SVT 8X10 with a 300w tube head. although SS if fine by me.

I played my Ric through a SWR Cab with a LMII head a few years ago and was blown away by its sound and power for such a small head. I think I might not like the speakers of MB more than the heads.

I am not playing out now so other than the garage jam type thing a 100 or 200 watt combo is fine for what I need.

I have 1 last ditch attempt at an amp coming on thursday. hopefully this one with do it for me...its not micro, its a "300" w combo with 2 10's.....always been a 15's kind of guy for the last 30+ years...well see how this works out