[Skylab]

Nice, Hans!

 

[IPodPJ]

Very nice, Hans. Congrats!

 

[boomana]

I admit it's gorgeous, but I'm still curious as to why Class D was chosen for a portable amp, since efficiency in portables has been pretty well taken care of and the sq problems of Class D are known. How have they been addressed here? Some folks I know with technical backgrounds have looked at the specs and aren't overly impressed, and dismiss that this amp delivers the high power that others are claiming are the benefit of Class D. I hope this amp is a winner, but until I understand the benefits of Class D in this application, and knowing some of the drawbacks, I'm suspicious until someone can answer why Class D was chosen and how the weakness have been addressed. Anyone know?

 

[Podster]

Quote:

Originally Posted by mrarroyo /img/forum/go_quote.gif Hans, that is a beautiful piece, congratulations! I am honestly not bothered by the yellow wire, all I care is how it sounds. I can't wait for you generous offer to allow me to listen to it. Thanks again.

Me either Miguel, I kinda thpught is was laid in and routed rather nicely for being the lone wire on the pcb

Absolutely stunning Han's, Ray has his UE's marked with RSA and you now have a nice iQube pair. Very well thought out chassis indeed and though I was a little opposed to the back side inputs I 'm now thinking I can make it work

 

[Sasaki]

From the spec, I noticed the fairly low output impedance of iQube.
Recently, I joined in NU FORCE IA7E audition (for speakers) and I was amazed by its extremely low output impedance, hence the great dumping factor.
I am not quite sure about the relationship but it could be the virtue of this type of switching amps.

 

[Skylab]

Vicki:

I think you are making to much of the "known sound quality problems of Class D". I recommend reading the recent article in The Absolute Sound about class D amps. Only someone with no clue how to design a class D amp would end up with an amp that didn't sound good.

There is a possibility that class D amps do have a "sound", but that is a matter of much conjecture.

I'm not sure why you are being so openly critical of Hans' design. It's nice that we are finally getting a portable amp that is in some way genuinely different than the rest of the pack. Who knows whether that will make it a winner or not. The proof will be in the listening.

 

[boomana]

Quote:

Originally Posted by Skylab /img/forum/go_quote.gif Vicki: I think you are making to much of the "known sound quality problems of Class D". I recommend reading the recent article in The Absolute Sound about class D amps. Only someone with no clue how to design a class D amp would end up with an amp that didn't sound good. There is a possibility that class D amps do have a "sound", but that is a matter of much conjecture. I'm not sure why you are being so openly critical of Hans' design. It's nice that we are finally getting a portable amp that is in some way genuinely different than the rest of the pack. Who knows whether that will make it a winner or not. The proof will be in the listening.

Hi Skylab, I'm not being critical, but I genuinely want to know why Class D was chosen, considering no one has yet chosen this in a portable as of yet (that I know about). I don't think that's unreasonable considering its uniqueness. We've got some amazing amp designers around and yet none have chosen Class D (I think Headroom has a desktop Class D iirc). I've been asking around and no one seems to have an answer except for why it isn't chosen. Perhaps this amp is breaking new ground. Wouldn't that be nice! But I'd also like to know what makes it special, when thinking about sq, not just beauty.

EDIT: I don't think it's any different than asking why someone chose a particular opamp over another.

 

[boomana]

So I just read the whole article, including the Editors' Roundtable, which seems to support my line of questioning, though they were talking power amps, not portables. This amp may be the best thing to happen to portables, but no one's saying why it's good, and the only one's I've heard from, or now read, are saying why not.

 

[Skylab]

So given that class D is more POWER efficient than class AB designs, and this means that MUCH longer battery life is at least possible with class D than traditional designs with equal power delivery, wouldn't that be a specific advantage to a portable amp?

 

[boomana]

Quote:

Originally Posted by Skylab /img/forum/go_quote.gif So given that class D is more POWER efficient than class AB designs, and this means that MUCH longer battery life is at least possible with class D than traditional designs with equal power delivery, wouldn't that be a specific advantage to a portable amp?

Absolutely! But we've got the Tomahawk with its reported 400 hrs with regular batteries, and the Li-ion batteries in some amps with mega hrs running time already. I'm wondering what other advantages there must be, thinking sq only.

Skylab, in my searching, I found this article, you and others might find interesting. It doesn't answer my sq questions, but it gets you thinking.

http://www.eetimes.com/news/latest/s...8501247&pgno=1

 

[Dexdexter]

Quote:

Originally Posted by boomana /img/forum/go_quote.gif Skylab, in my searching, I found this article, you and others might find interesting. It doesn't answer my sq questions, but it gets you thinking. http://www.eetimes.com/news/latest/s...8501247&pgno=1

Great link, Vicky!

It's nice to see folks beginning to discuss the pros and cons of Class D amplification here, something that I have no personal experience with other than reading about it.

As I mentioned previously, the reputation of Mssrs. Putzeys and Tent in the field were what really piqued my interest in the iQube to begin with, so it will be fascinating to discover how a portable design from them works out in practice. But, knowing Hans and how fussy he is, I suspect it's gonna be pretty special.

Just spotted this over on the ipa thread:

It's even further reassuring to see that Hans managed to commission Steve Jobs for packaging detail!

 

[Skylab]

Wow that does look nice.

I guess the point I was trying to make is that I believe class D in a portable does offer some intriguing possibilities, like the same 400 hours run time you get from a Tomahawk, but with more power delivery. Perhaps 400 hours from 9 volts instead of 3. This can have sonic benefits.

For example, I use my Meier Move in high-current mode, because it sounds better that way. This is a hallmark of class AB designs. And it means I get less battery life than I would if I used low current mode. This is a trade off that, PERHAPS, class D would eliminate.

And I guess finally, my reason for jumping in here is that I think we should all be ENCOURAGING new thinking and innovation in this space. I don't see that we need another amp that's just more of the same.

 

[hoosterw]

Well be honest Dex, wasn't it windows that copied apple's software user interface in first instance as well after the DOS era?

Hans.

 

[mrarroyo]

Beautiful indeed! I look forward to hearing it.

 

[Dexdexter]

Quote:

Originally Posted by hoosterw /img/forum/go_quote.gif Well be honest Dex, wasn't it windows that copied apple's software user interface in first instance as well after the DOS era?

Haha, too right, Hans, everything goes around...

I particularly enjoyed reading over at the other place that the design aesthetic for the iQube was inspired by a vintage Braun shaver!

Of course, Apple seems to have traveled down the Braun path recently also: