Are Class D amps really 5 times less powerful than A/B?

[marchone]

But too often other people chime in with an air of authority when in fact they don't know their ass from their elbow about the topic. It takes a while for new folks to figure out who to listen to.

It doesn't take long. There are always plenty of support posts and likes to figure it out.

 

[bdplaid]

No it doesn't. Digital means that the "information" (or "signal") is represented by numbers. The numbers don't have to be 1s and 0s. Of course in practice if the numbers are going to be transmitted or stored electronically they will end up as a series of on and off states, but digital audio processors are operating at a numeric level, not an on/off level. Given enough paper and ink you could take the digital data from an audio CD and print it out on paper as a series of base 10 numbers, transport the paper copy somewhere, and then scan the data back into a computer, and at all points in that process the audio data would still be digital.

Hence the name, Digit.

 

[azureblue]

I have a GK MB212. The power supply blew - I opened it up and discovered the amp is a GK Preamp driving an ICE stereo power amp, that has a self contained power supply. All of $135 to replace. 6 connectors, 6 screws and back on operation.. The replacement was an identical copy.
Bang & Olufsen ICEpower 125ASX2 2x125W Class D Amplifier -- a stock, off the shelf unit, gotten from ebay..
As it turned out, the blowout was due to a thermistor, which I am waiting for the replacement part to come in. A design flaw - they surfaced mounted a component that gets hot, when it should be off the board. I found some paperwork on it that shows how to drive it, so it will probably be an amp for an extension cabinet. I am also going to try to see if I can drive it with a bass preamp. There is a kit for it that is a box and connectors - apparently, there is a whole little industry for these things.. While it is rated at 125PS, the power goes up to 240 PS at 4 ohms. Yes it will handle low B very well.

 

[And I]

A watt is a watt-- unless it's a Bugera amp in which case a watt is 1/4 of a watt.

A speaker driven by a "digital" amp would have to be a "digital" speaker? Only produces square waves? Exists only in 2 dimensions? Perhaps the D/A conversion is done psychoacoustically? Perhaps it just dispalys a waveform shape and you have to imagine what it sounds like? Perhaps you can only play a bass with 1 string and 1 fret through it?

 

[HolmeBass]

I haven't found this to be true when comparing using the same speakers, with the same LF extension and sensitivity.

Yeah, in my limited gigging experience with other people's tube amps, I found that when they had to get loud the got pretty distorted. And I found that distortion to be very pleasing, and the bass was spotting into the mix in a very cool way. Also some very cool note bloom.

But when push comes to shove, my hybrid amps that are rated higher are significantly louder.

I've never compared amps head-to-head on a gig, and my hybrid / SS power section amps have always output more watts into my speaker load.

That said, I also now know that the difference between 300W and 550W is not a huge difference, so while I get the appeal of a tube power section, I don't think they actually are louder. I do think you can max them out and still have a great tone, which is not the case with most SS power amps.

I grant this is my opinion and derived from the limited experience of 3 different gigs.

 

[JimmyM]

I don't think there is a remarkable difference in how class D and class A/B amps translate power into volume. One could argue about subjective things like tone or response.

When comparing SS to tubes, that's a different story. A 300 watt tube amp can be very loud. A 300 watt SS amp is barely good enough for small room gigs with a quiet drummer and guitar player.

I haven't found this to be true when comparing using the same speakers, with the same LF extension and sensitivity.

Me neither, and I am a tube snob. A very bad tube snob who owns a couple micros and uses them, but still…

 

[Texican]

Just want to make sure I read everything right… so we are saying that class D stands for digital, right?…

 

[MultiScaleMale]

Just want to make sure I read everything right… so we are saying that class D stands for digital, right?…

It's the common misconception, but was first developed in like 1955. So, no. It doesn't stand for "Digital". It stands for D, a type of topology.

 

[bdplaid]

I've seen amp power rated at 5% thd.

 

[kittywithabanjo]

I just worry about does it sound good and does it do the job

 

[patrickhowell]

It's so refreshing to see some plain common sense comments about vinyl, in contrast to the usual "audiophile" mysticism BS about how much greater it sounds than digital media. Personally, I don't miss listening to scratched, noisy, warped, dusty or plain worn out LPs at all, or shellac 78s / wax cylinders. Gimme HQ streaming played through modern high quality gear every single time.

Some records sound better when remastered for vinyl. This has nothing to do with the medium itself, but assumptions the engineer can make about how the audience will listen to the music. Instead of being forced to compete in the loudness war on Spotify or making sure that it sounds as good as possible through iPhone speakers, they can simply apply the most appropriate mix and dynamic range for the recording.

 

[agedhorse]

I've seen amp power rated at 5% thd.

Depends on the application. If the ability to overdrive is part of the marketing, it better be able to deliver power under distorted operation reliably.

I have a GK MB212. The power supply blew - I opened it up and discovered the amp is a GK Preamp driving an ICE stereo power amp, that has a self contained power supply. All of $135 to replace. 6 connectors, 6 screws and back on operation.. The replacement was an identical copy.
Bang & Olufsen ICEpower 125ASX2 2x125W Class D Amplifier -- a stock, off the shelf unit, gotten from ebay..
As it turned out, the blowout was due to a thermistor, which I am waiting for the replacement part to come in. A design flaw - they surfaced mounted a component that gets hot, when it should be off the board. I found some paperwork on it that shows how to drive it, so it will probably be an amp for an extension cabinet. I am also going to try to see if I can drive it with a bass preamp. There is a kit for it that is a box and connectors - apparently, there is a whole little industry for these things.. While it is rated at 125PS, the power goes up to 240 PS at 4 ohms. Yes it will handle low B very well.

First of all, that's the module that was counterfeited by a supplier in China, most that are sold over the net are counterfeits and they have shown to be (very) unreliable. It's virtually impossible to tell cosmetically.

Second, you have your power ratings terribly confused.

 

[db59]

on to page 14

 

[el murdoque]

So if Class D to Class A/B Solid state is calculated with the factor 1/5, and tube amps are three times as powerful as SS amps,

The factor to calculate Tube Watts vs. Class D watts is 15. Good to finally know.





I can sell my 500W Class D head and get a 33W Tube head and be done with it now

 

[LeonineAlpha]

I heard a rare recording of TS Eliot reading the Wastelands on

Wax Cylinder!

Really showed vinyl up for the synthetic medium it is. You can feel the love of the Bees

Wish I could record that straight to 8 track, now thats analog... and its portable, playable on moving vehicles without skipping.

Also, Eliot sounds like Vincent Price, but sadly got his social commentary from Morras, literally just translated French magazines for his famous quotes.

Thus he was a diehard beeswax audiophile, organic model, hierarchical hive insects with a queen and all that.

 

[Texican]

It's the common misconception, but was first developed in like 1955. So, no. It doesn't stand for "Digital". It stands for D, a type of topology.

Yeah but digital starts with D right? So all amps are digital. Drums too. I'm pretty sure I have this right

 

[mambo4]

It's so refreshing to see some plain common sense comments about vinyl, in contrast to the usual "audiophile" mysticism BS about how much greater it sounds than digital media.

I always laugh at Vinyl audiophiles claiming it has a "pure" signal, ever since I learned about the role RIAA amplifiers in recording and playback of vinyl records. The physical limitations of grooves on vinyl require signal compromise and manipulation in a way that digital recordings do not.

 

[JimmyM]

Yeah but digital starts with D right? So all amps are digital. Drums too. I'm pretty sure I have this right

Drums are definitely digital.

 

[sawzalot]

Everyone knows that Class AB watts are more powerful than Class D watts. This is because "AB" stands for "Awfully Big", while "D" stands for "Diminutive". That clears things up right away. Also "D" is often associated with "digital", which class D is not, but digital is all about 1's and 0's and as we all know those are very low numbers so they must be less powerful than Awfully Big watts.

Also, it should be noted that all of these watts are different than Class I watts or Class T watts. As we all know, the class I amplifier recycles the power coming back from the speaker, processing it through an advanced Flux Capacitor to "clean" the power and return it to the power grid, thus lowering the user's electric bill. Class T of course relies on an Arc Reactor to use fusion to massively amplify small signals ("T" obviously means "Tiny") using the near limitless power provided by the Palladium core. The primary downside to this amplifier design is the thread of destroying the universe if it overheats.

Finally, the "great grandaddy" of all forms of watts are "Tube" watts, which are the best because they provide power in the heaviest form factor possible. They must be the best form of watts because they d*mn well better be after forklifting the 8x10 onto the stage and straining your back moving the giant tube head on top of it.

 

[Texican]

Drums are definitely digital.
View attachment 4693948

It's a shame that we can't get class D cymbals, but I fear the digital artifacts would cause "tube cymbals are louder" threads all over the drummerworld forums.

Zildjian makes nice Class-K's tho