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CEntrance DACport & Ayre QB-9 - Page 3

post #31 of 34
Quote:
Originally Posted by mgoodman View Post

Hi Gabriel and thanks for the idea. While it's a great idea to use two USB ports for power-hungry hard drives, etc., using two ports is less convenient than one and a special cable is required (which can be lost, etc.) Fortunately, none of this is needed, since about 380mA is all that DACport consumes in normal operation. 500 mA is simply not needed.

 

My point was to say that we optimized the circuitry inside DACport so well, that it runs well below the limit. It's always a good engineering practice to leave a little extra margin, for a couple of reasons:

 

1) Not all laptops are created equal. Some laptops don't give full power to the USB jack, others only have one USB port.

 

2) Our customers would appreciate longer battery life that results from lower power consumption, while enjoying great audio quality and the ability to drive any headphones very loud.


So are you saying current users wont benefit from a dual port cable then?  I'd rather not bother diggin up one atm if its not worth the effort.  biggrin.gif

post #32 of 34

Michael,

 

 

Thanks for replaying my Post.

If my math is right using 380mA on 5V translates to 1.9W

From that you will probably need to allocate about half to the digital circuits so we are left with something like 1W for the AMP section which might be a little too short for some demanding headphones.

 

Drawing 380mA from another USB port will allow the AMP section to go to 3W which means 3x the power (drawing 200mA instead will be enough to double AMP power).

I don’t think losing the specialty Y cables is a big problem as a new one can be bought for $10-$20.

As for draining batteries faster, this is only a problem when mobile, and if both options can be used then people can use lower power when mobile (probably with smaller phones) and full power while sitting at their desk.

 

Thanks again

/gabriel

 

 

 

Quote:
Originally Posted by mgoodman View Post

Hi Gabriel and thanks for the idea. While it's a great idea to use two USB ports for power-hungry hard drives, etc., using two ports is less convenient than one and a special cable is required (which can be lost, etc.) Fortunately, none of this is needed, since about 380mA is all that DACport consumes in normal operation. 500 mA is simply not needed.

 

My point was to say that we optimized the circuitry inside DACport so well, that it runs well below the limit. It's always a good engineering practice to leave a little extra margin, for a couple of reasons:

 

1) Not all laptops are created equal. Some laptops don't give full power to the USB jack, others only have one USB port.

 

2) Our customers would appreciate longer battery life that results from lower power consumption, while enjoying great audio quality and the ability to drive any headphones very loud.

post #33 of 34
Hi Gabriel,

DACport takes about .5W for digitial and leaves about 1.5W for analog circuitry. We've found that this will drive most headphones very loud. DACport's circuitry is tightly optimized already, meaning that all internal systems (power supplies, converters, amps) are all tweaked out or best performance together. In order to get more juice out of the headphone amp, you'd need to run it at a higher voltage and feed a hotter signal. Incidentally, that's exactly what DACmini does (some people feel it's almost too loud).

http://www.dacmini.com

And yes, this means that you cannot power the whole thing from a single USB Jack anymore. That's why DACmini uses an external power supply.

In the case of DACport, in order to make those changes and run it even hotter than it does, you'd need to pretty much redesign the entire product. We're using 0402 SMT components on two gold-plated PCBs inside and everything is very tightly packed. So if you change one thing, something else will also need adjustment. Before you know it, you have a different product in front of you and the original intention has been lost wink.gif

I suggest you try DACport as is (we offer a 30-day trial) and let me know if it's loud enough for your needs. As it stands, DACport will not benefit from using a split USB cable - it simply wouldn't know what to do with the extra power.

Cheers,
post #34 of 34

 

Thanks for the replay

I will take advantage on the 30-day trial on my next visit to the US in few weeks time

 

regards

/gabriel

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