[zilch0md]

Congrats!

 

[rbf1138]

Would you guys say that the Dacport LX would be a good compliment to my Headstage Arrow 4G? I'd be pairing it with a Macbook Air. 

 

[zilch0md]

I'm not familiar with your amp, but I'm comfortable saying that the DACport LX will warm your signal very slightly - it's almost neutral.
 
Mike

 

[lee730]

I just love my DACpot LX. After changing out to my new Alienware Aurora the glitches I use to get have stopped and the sound appears to be better. The popping use to happen on the Area 51 when accessing files or browsing the web.

 

[zilch0md]

Sweet!  It's nice when everything's working as it should!  "Glitches" can get under your skin after awhile.  

 

[zilch0md]

Head-Fi member kkl10 and I exchanged PMs a couple of weeks ago on the subject of supplying clean power to the DACport LX (or any other USB-powered DAC).  
 
We were discussing the idea of supplying power exclusively from the 5V jack of a Lithium-ion battery pack, such as the Energizer XP8000A or the the longer-lasting and less expensive Anker Astro3 (which can deliver 5V to loads as high as 2 Amps).
 
In one of my PMs, I wrote:

I want a splitter that does this:  Two USB Type A connectors - one for power and one for data only.

 
To which kkl10 replied:
 

I'm using an Y USB cable just like the one you show and simply use a small piece of electrical insulation tape to cover the 5V pin in the main type A connector, the one for both data and power.

 
Great idea!  That way, only data comes from the laptop and only power comes from the external battery pack!
 
Here's the cable I ordered:
 
 
   
 
 
 
 
 
   
 
 
There are several dual-power USB adapter cables out there, but I ordered this one because its cables are short and I'm assuming that if its made for LaCie, it's probably well-constructed.  
 
The LaCie USB Dual Power Sharing Cable for Rikiki can be ordered from these two sources (and others, perhaps):
 
     http://www.bhphotovideo.com/bnh/controller/home?O=&sku=670128&Q=&is=REG&A=detail
 
     http://www.datavis.com/cgi-bin/product.cgi?prrfnbr=518217
 
Here it is, hooked up to my DACport LX, getting only data from the laptop and clean, 5-Volt, 2-Amp power from the Anker Astro3:
 
 

 
As I've mentioned previously, in the other DACport thread, I keep the Class A DACport LX cool by setting it on an aluminum heat sink.  
 
The analog output of the DACport LX is connected to the RCA inputs of a DACmini CX (at the moment) using a Monster MCL MST2FR Stereo Female RCA to1/4 Stereo Male Cable Adapter and a pair of Emotiva XRCA .5 Meter RCA Interconnects.
 
And what about the sound?   I was really surprised.   I haven't been having any problems with noise coming from my laptop, when running the DACport LX on the laptop's USB power, with my iBasso PB2, for example, while traveling...
 
 

 
A couple of weeks ago, at Navarre Beach, Florida, the Energizer XP8000 battery pack and an XPAL Willy Cable WI16 inline voltage regulator was used to provide 16VDC to my iBasso PB2 (its maximum permissible supply voltage), with the DACport LX getting its power from the USB port.
 
This morning, having swapped the DACport LX between laptop power and external battery power, across several tracks, I was immediately struck by how much more authoritative the DACport LX sounds when using the battery pack.  Dynamics are noticeably improved.  I didn't see this coming.  I had thought I might hear a lowering of the already low noise floor, but instead, with my little 10-inch netbook, where I intentionally read my WAV files from SD cards instead of  using the hard drive, I'm only hearing improved dynamics - as if the DACport LX has more current to work with than it did on laptop power.
 
It might just be that my little laptop's 5V USB ports are "weak" - I know they will not charge my iPad Mini, for example.  USB ports are supposed to deliver 5VDC and handle current demands of at least 500mA, but I've read that some PCs have USB ports that can deliver as much as 1 Amp  (1000mA).   The Anker Astro3 is rated at 5VDC and 2 Amps (2000mA) - plenty of clean, 5V power for a USB-powered DAC!
 
There's no change in the already dead silent noise floor, with my netbook, but I'm thinking anyone who is struggling with "noisy" USB power and wants to remain "transportable" without reliance on AC power, might benefit from this $60 solution (Anker Astro3 + LaCie USB adapter cable), as opposed to something like the $199 iFi iUSBPower.
 
Thanks for the suggestion of taping that 4th pin, kkl10!
 
Edit:  You can easily test if the tape is adequately blocking power from the laptop, just by hooking up your DAC and the laptop connector first - if the DAC doesn't come to life, the tape is still doing the trick.  Connect the external 5V supply and you're good to go, with only data coming from the laptop.
 
Mike

 

[lee730]

Very interesting. Mike have you ever tried a powered usb hub? I wonder how that would compare .
 

 

[zilch0md]

Quote:

Very interesting. Mike have you ever tried a powered usb hub? I wonder how that would compare .
 

 
I've not tried that, but I would think it could make an improvement for someone with either a low current or noise problem on their laptop, but, depending on the USB hub's design and how the power comes in from the AC outlet (switch mode vs. linear), it could go either way - a hub could improve things or it could make it worse.  You would just have to listen to know for sure. Using an AC-powered USB hub would, however, defeat the convenience of not being tied to an AC outlet with a USB-powered DAC.
 
Mike

 

[lee730]

How does the battery qualify as clean power though? I'm just curious as when even powering my PC from the backup battery supply it was on the nosier side of things? I'm quite interested in trying it out though .
 

 

[zilch0md]

lee730,
 
If you're talking about powering the laptop or PC with a battery, instead of using an AC outlet to power the machine, you are still exposing your USB-powered DAC to the noise that can come from other circuits in the laptop or PC - noise from the graphics adapter, cooling fans, or the hard drive, for example.    
 
But if you are providing the DAC (or audio amp) with 5V power from a battery pack, it's generally safe to say that the battery pack will provide "cleaner" power than the power that comes from a PC or laptop's USB port.  But that's not always the case.  In fact, the people who manufacture the iFi iUSBPower claim that the 5V output from that AC-powered external 5VDC power supply is many times less noisy than the power from a standalone battery pack.   So, batteries can be noisy, too, apparently.  Especially if the battery pack is using some kind of switch mode circuit to create 5V from a higher voltage (rather than using an expensive, designed-to-be-clean, DC-to-DC converter chip, which I suspect is what one would find within the $199 iFi iUSBPower.)
 
Mike

 

[DoomForce]

Edit: 
Thanks for sharing all this. As far as modding goes, this solution is both elegant and relatively cheap. Props!

 

[zilch0md]

Quote:

Edit: 
Thanks for sharing all this. As far as modding goes, this solution is both elegant and relatively cheap. Props!

 
Glad you think so, thanks!
 
I'm really pleased with the sound. I had no idea the DACport LX was starved for current with my netbook.  It's happy now!   
 

 

[zilch0md]

I just got a CEntrance DACport - it sounds GREAT with the Beyerdynamic DT1350!
 
Awesome synergy.  The DACport warms things up just a little bit, delivers lots of bass control and plenty of detail.  This makes for a nice little package (DAC + amp).
 

I'm interested in critically comparing the DACport to the DACport LX + Stepdance, but for now, I'm just enjoying the tunes!   

 
Mike

 

[zilch0md]

Coming soon...
 
 
    VS.  
 
WAV > Foobar 2000  with WASAPI event mode > CEntrance DACport LX (on Anker Astro3 external 5V battery pack) > Milian Acoustics SPOFC interconnect > Meier Audio Corda Stepance (on Energizer XP8000 15V external battery pack) > Beyerdynamic DT1350
 
vs.
 
WAV > Foobar 2000 with WASAPI event mode > CEntrance DACport (on Anker Astro3 external 5V battery pack) > Milian Acoustics SPOFC interconnect > Meier Audio Corda Stepance (on Energizer XP8000 15V external battery pack) > Beyerdynamic DT1350

 

[zilch0md]

DACport LX vs. DACport - An attempt to identify their sonic differences
 
Quote:

 

Spoiler: Pics%20from%20prior%20post.

 
 
    VS.  
 
WAV > Foobar 2000  with WASAPI event mode > CEntrance DACport LX (on Anker Astro3 external 5V battery pack) > Milian Acoustics SPOFC interconnect > Meier Audio Corda Stepance (on Energizer XP8000 15V external battery pack) > Beyerdynamic DT1350
 
vs.
 
WAV > Foobar 2000 with WASAPI event mode > CEntrance DACport (on Anker Astro3 external 5V battery pack) > Milian Acoustics SPOFC interconnect > Meier Audio Corda Stepance (on Energizer XP8000 15V external battery pack) > Beyerdynamic DT1350
 

 

 
After a couple of hours of careful A/B testing I am amazed at how similar the DACport is to the DACport LX.  I really didn't expect a great difference, but found them to be closer still.
 
Selecting The Gear
 
I consider this to be a fair comparison, given that the Meier Stepdance is known to be very neutral and transparent - allowing me to listen to the DACport LX without adding much of anything (other than amplification) to the signal.
 
The Stepance uses OPA1611 op-amps.  If the Texas Instruments datasheet can be trusted, the OPA1611 produces its lowest THD + Noise figures with a supply voltage (Vs) of 15 Volts.  Thus my choice to power the Stepdance with the Energizer XP8000 and a 15V inline voltage regulator cable - the XPAL Willy Cable WI15.  The goal in this case, being to make the Stepdance as transparent as possible, more so than to increase the headroom, which helps so much with inefficient headphones like the LCD-2.
 
The DT1350 seemed the best choice from among the headphones I have, for its relatively uncolored sound, terrific bass extension (with no roll-off in the bass), great detail, but most importantly, its efficiency.  I didn't want to disadvantage the DACport's amp section relative to the DACport LX with Stepdance, by using a harder to drive headphone like the LCD-2 or T1.  The DT1350 isn't perfectly neutral, of course, but whatever it brings to the table will be a constant when comparing the DACport to the DACport LX.   With its 80-Ohm impedance (exactly 8 times the output impedance of the DACport's amp section), the difference in output impedance between the Stepdance (at < 1-Ohm) and the DACport (at 10 Ohms) will, theoretically, have no impact on the sound heard at the DT1350.  (This wouldn't be the case if the ratio of the headphone impedance to either amp's output impedance was less than 8:1.)
 
Lastly, previous testing has revealed that my netbook's USB ports, though not noisy, fail to supply as much current as I can get using the Anker Astro3 battery pack's 5V ports, where a whopping 2 Amps can be delivered if either the DACport or the DACport LX demand it.  The modified Y-cable, discussed in an earlier post, above, pulls only data from the netbook, with power coming only from the battery pack. 
 
So, I've done pretty much everything I can think of to ensure that both the DACport and DACport LX are free to do their thing without inhibitions.  

 
Impressions
 
I began by volume matching the two chains pictured above, to 85.0 dB, using a Bink Audio white noise WAV file and the JL Audio SPL meter iPhone app with a lapel mic between the ear pads. 
 
It's hard to quantify the degree to which any particular sonic trait differs when trying to communicate what you've heard, but in everything I write here, please understand that it's all very subtle.  
 
The DACport is less neutral than the DACport LX + Stepdance.  The DACport adds a bit of warmth to the mids that's very appealing, but there's also a little less sparkle in the highs, with less air.  And the DACport is just a wee bit smoother in the highs - just a tad less detailed.  Here's the biggest surprise - but remember, it's still a subtle difference, not dramatic.  I'm convinced the DACport enhances the bass energy just a little, too, but with efficient headphones like the DT1350, the bass is just as tightly controlled, with good pitch discrimination, as with the DACport LX and Stepance.
 
I don't write critical reviews very often, and I don't consider myself to be very good at assessing or communicating differences in sound stage or imaging, but I'll stick my neck out here and say that I find the DACport to be a little less forward, more laid back in its presentation.  
 
That's it!  In summary, I'll say that if you're trying to decide between getting a DACport LX with external amp and a DACport, in my opinion, the only justifications for getting the DACport LX for use with an external amp would be to gain more power for less efficient headphones, to secure a slightly more detailed source, or to "cool" a headphone that is already somewhat warm or dark, rather than making it slightly more so with the DACport.
 
Edit:  There are, of course, other factors that can't be ignored, in choosing the LX vs. the non-LX - that have nothing to do with sound quality - the most prominent being the convenience of the DACport, which is pretty cool.   I'm taking mine to work with me until further notice!
 
Mike