[lee730]

Cool Mike. I may have to give that a whirl. Even that power supply for the USB (idevice?) seems very interesting. I really do enjoy my LX .
 

 

[deniall83]

Thanks for the suggestion but the Dacport LX doesn't have a headphone amp does it?

 

[zilch0md]

No, it doesn't.   

 

[deniall83]

So I would still need a headphone amp to drive my HD650?

 

[morpheusx]

Quote:

Thanks for the suggestion but the Dacport LX doesn't have a headphone amp does it?

 
 
Quote:

No, it doesn't.   

Actually DACport LX does have headphone amp but locked at line-level.
DACport amp = DACport LX amp
the only difference between DACport and DACport LX is DACport using volume potentiometer and LX using fixed-resistor divider

 

[zilch0md]

That's true, but for deniall's sake, I'll add that the absence of a volume control on the LX means, you will need a headphone amp.

 

[deniall83]

Normal DACPort for HD650 or 1 ohm mod?

I'm after a nice clean sound..

 

[zilch0md]

Quote:

Normal DACPort for HD650 or 1 ohm mod?

I'm after a nice clean sound..

 
With the disclaimer that I've never heard either the HD600 or the HD650, I believe there's a consensus that would say the HD650 is less neutral than the HD600 - that it's colored in a way that's more "fun" than it is accurate in frequency response.
 
IF you believe that to be true, I would encourage you to go for the 1-Ohm output impedance mod with the DACport.  CEntrance (and others) say that the 1-Ohm version is more neutral, where the default 10-Ohm version is warmer and more "musical."
 
I for one, wouldn't try to mix a "colored" DAC and amp with a "colored" headphone.  It's possible that you might really love the result, but if you like the way your HD650 sound right now AND you know that you're currently sending it a reasonably neutral signal, again I'd say, go for the 1-Ohm mod.
 
Wishing you good luck with this, as I'm speaking theoretically, not from experience.
 
Mike

 

[zilch0md]

If anyone's interested in improving the power quality to the DACport or DACport LX (or any other USB-powered DAC), here's a micro-review I posted to another DACport thread, on a $60 solution for clean 5VDC power (for current demands up to 2 Amps), that's still "transportable" without reliance on AC power - a method that receives power exclusively from an external Lithium-ion pack, receiving only data from the laptop:
 
http://www.head-fi.org/t/615548/do-the-dacport-and-the-dacport-lx-really-sound-different/30#post_9292387
 
 

 
Mike

 

[zilch0md]

I've posted an article comparing the DACport to the DACport LX.
 
Mike

 

[nathan_h]

Quote:

Yes, I had the 10 Ohm and sent it in for the 1 Ohm mod.  Much better control of the bass and seems to be more even in the FR from low to high.  I'm using low ohm custom IEMs (UM Miracles) so I didn't want to color the sound at all.  With higher Ohm headphones you probably wouldn't notice much difference.

I'm using some AKG 550 with my DACport.  They are pretty easy to drive/sensitive, so I was at first having tracking errors at low volume levels (on the DACport).  
 
I sent it in to Centrance and they replaced the volume pot and maybe made other adjustments (I let them know what cans I was using).  Cost about a hundred bucks, but worth it.
 
The volume tracks better now.  At low levels before, one channel cut out before the other.  Now I have lots of range in the lower volumne levels.  Also, the occasional crackle when changing the volume is far far less than before.
 
But since the AKG550 are about 60 ohms, the ideal resistance for a headphone amp would be below 6 ohms....  rather than the 10ohms that the standard DACport is rated at (to achieve the best damping factor).  So the 1ohm mod is of interest to me.
 
Two questions:
 
1) Perhaps CENTRANCE made that mod when I sent it back, and that is why I have more range in the lower volume space already?
2) How much did CEntrance charge you for the 10ohm to 1ohm mod?

 

[namaiki]

It's about $100 for the 1 ohm mod.
 
Link: http://centrance.com/store/cart.php?target=category&category_id=263
 
 
For me, I purchased my DACport with the mod and it has a sticker on the bottom which says this.
 
*looks at bottom of DACport to confirm this*
 
...though it's starting to rub off.
 
 
I still have a bit of channel imbalance at low volume and the crackling when changing the volume issues though.  I probably should send mine in to be fixed.
 
Just wondering, is it normal to have channel imbalance for lower than about 9 o'clock on the volume knob?

 

[nathan_h]

Somewhat normal to have issues at very low volume levels.  This is not unique to Centrance nor the DACport, but true of all or most analog volume controls.
 
I checked with Centrance about what work was done on mine. I do NOT have the 1ohm mod.  They actually recommend against it, given my cans are sensitive and I've already achieved a 6 to 1 ratio for good damping (even though 8 to 1 or higher is ideal).  
 
Why?  
 
Because the mod would make low level volume tracking less linear and stable -- and achieving more range, linearity and stability at low volume levels was the whole reason I had them open mine up and replace & adjust the volume pot in the first place.  So, for me it was a successful fix.  Going with the 1ohm mod, to achieve more damping, would mess up my low level volume quality.... which is not a great trade off.

 

[namaiki]

I wonder, would it affect sound quality in a bad way if I used the "airplane adaptor" from my TF10s to make the headphones harder to drive so I can use a higher volume to avoid channel imbalance at lower volumes?  (my main cans are 25 and 42 ohm with normal listening volume around 9 o'clock)
 
See photo: https://www.dropbox.com/s/vklhvq1pe0jucja/IMAG0346.jpg (what a mess but it's what I had available, lol)
 
Edit: I stopped doing this because it was mucking with the crispness of the sound and dynamic range of the headphones.

 

[nathan_h]

Yes, I would think so.  Certainly in concept it's not a problem.  Now whether that particular piece of kit is of good enough quality not to cause a problem is not known to me, but the idea of attenuation is valid, imo.