Why Choose Class D for a Portable Amp?

[boomana]

So, this is coming out in a week. As I'm busy trying to learn about such things, I'm curious as to why someone would choose to build a Class D portable amp, or if it's such a good idea, why, with the explosion of portables, hasn't it been done more (I think Headroom has a Class D desktop, but I don't know of others)?

http://www.i-qube.nl/index.php?id=18

EDIT: I'm thinking mainly in terms of sound.

[boomana]

the battery life should be very good.

Okay, but battery choices are plentiful. My damn little Diablo has been going for a few days straight, and isn't the Tomahawk supposed to go for 5,000,000 hours on a couple AAA? Is there any sq advantage, or is this more about efficiency and novelty?

[Mister X]

Maximum output power per channel from 20-20,000Hz:

160 mW_16 ohm

80 mW_32 ohm

12 mW_200 ohm

Ouch.... makes me wonder why they bothered with a class D chip as well.

Especially with 4 AAA batteries....

The case is pretty novel though

[granodemostasa]

it's cute... i'm sure someone out there will like it. at least it's novel...

[elnero]

it's cute... i'm sure someone out there will like it. at least it's novel...

$550.00 US (approx.) is pretty expensive for cute and novel. For a portable amp at that price I'd expect it to be borderline ground breaking.

[boomana]

So I get the whole high power, high efficiency thing, but forgetting battery life and some ooomph, what about sound? I'm mostly wondering why people haven't been making Class D portables since good battery life and power isn't a bad thing? Sorry for the noob questions, but I'm really curious. Are there disadvantages to sound, even if the power can drive Senns, for example? What do you lose by going that route?

[n_maher]

I'd hardly call those specs high power, the mini3 puts out about 3x that much into 330ohm. I wonder how low the i-qube's output would be with a load like that?

[boomana]

I'd hardly call those specs high power, the mini3 puts out about 3x that much into 330ohm. I wonder how low the i-qube's output would be with a load like that?

I guess I was referring to what I've been told as the advantages of Class D in general. So is there any point to this amp other that looking cute? I'm not interested in getting one, but just in why it was made that way.

[Filburt]

I choose Class D because I am a _huge_ fan of switching noise, phase shift, and bizarre, complex distortion spectra. Those things really improve my listening experience and I could not go without them.

[n_maher]

I choose Class D because I am a _huge_ fan of switching noise, phase shift, and bizarre, complex distortion spectra. Those things really improve my listening experience and I could not go without them.

[philodox]

I choose Class D because I am a _huge_ fan of switching noise, phase shift, and bizarre, complex distortion spectra. Those things really improve my listening experience and I could not go without them.

LOL, great post.

[hYdrociTy]

FILBY IS BACK

(>'-')><('-'<)

[aerius]

I choose Class D because I am a _huge_ fan of switching noise, phase shift, and bizarre, complex distortion spectra. Those things really improve my listening experience and I could not go without them.

Well, in that case you'll really love SACD, and any CD player or DAC which uses a single-bit D/A converter chip.

[Filburt]

Well, in that case you'll really love SACD, and any CD player or DAC which uses a single-bit D/A converter chip.

Of course! I also don't want to miss out on sweet, sweet quantization noise in the audio band

[Icarium]

Jesus SACD is flawed in that fashion? I probably can't even hear it, but I had no idea. I have some decent sounding SACDs.

[Dusty Chalk]

Yeah, there's a lot of high-frequency hash on SACD output, but it's much higher in the case of DSD than it is in, for example, a filterless DAC at 16/44.1. The bright side is that it's more phase-correct, which is why SACD's are still so pleasant to listen to.

That said, unless you've heard a filterless DAC, you'll never know which you prefer. Some people prefer filterless DACs even at 16/44.1.

[spritzer]

There is a reason why DSD is converted over to 24bit PCM in many players. Still DSD is in its infancy while PCM is more then 60 years old

[Dusty Chalk]

There is a reason why DSD is converted over to 24bit PCM in many players.

I'm not sure what reason you're trying to imply here, but the reason most of them convert is to cut costs.

[spritzer]

I'm not sure what reason you're trying to imply here, but the reason most of them convert is to cut costs.

I wouldn't call a APL NWO3.0GO cheap and they do it for better performance. DSD will sound much better in 20 years time but now it's better to convert over to PCM.

[philodox]

Oh yeah, well I convert DSD to PCM for fun!

[Dusty Chalk]

I wouldn't call a APL NWO3.0GO cheap and they do it for better performance. DSD will sound much better in 20 years time but now it's better to convert over to PCM.

I humbly disagree. I know of at least two high-end upconverters that convert 16/44.1 PCM to DSD, and they're both considered desirable (Meitner, dCS).

[spritzer]

That's true but both have a vested interest in DSD (both are big in the pro sector) and neither can match the APL in engineering.

[deepak]

That's true but both have a vested interest in DSD (both are big in the pro sector) and neither can match the APL in engineering.

Can you tell us a bit about the APL engineering? Because reading their forums, there isn't much technical info other than a whole lot of ass kissing (or audio masturbation).

[grawk]

I'd be willing to bet that a single guy doing cd player mods isn't doing more engineering than meitner or dcs...but you're welcome to think otherwise.

[deepak]

I'd be willing to bet that a single guy doing cd player mods isn't doing more engineering than meitner or dcs...but you're welcome to think otherwise.

I'm not frowning on dcs or Emm Labs (and I agree with you).

I'm actually really curious to hear about what goes into the APL players (given the relatively little technical information I've found on the web, other than hearing "it's the greatest digital player ever" ad nauseum), and if spritzer has some information I'd like to hear it.