[dryvadeum]

The XP8000 has been replaced by the XP8000A.   I've not thoroughly researched the XP8000A, but at first glance, it seems to be identical in terms of features and performance.

The XP18000 is a much larger battery pack that has been replaced by the XP18000A.

XP8000A:   http://www.energizerpowerpacks.com/us/products/xp8000a/

XP18000A:  http://www.energizerpowerpacks.com/us/products/xp18000a/index.html

As to your question - I would say you should not consider spending the money for a higher voltage external power supply unless you have relatively inefficient headphones that can enjoy an increase in power output from the amp.

Mike

They're pretty expensive for what they are. I've bought a rechargeable battery and charger so I'll see how that fares before I invest in something else.

 

[zilch0md]

Quote:

They're pretty expensive for what they are. I've bought a rechargeable battery and charger so I'll see how that fares before I invest in something else.

 
 
That's a perfectly reasonable decision.  
 

 

[Dark Helmet]

Quote:

I got my Quickstep today. Damn this amp is amazing - it's so detailed and transparent. I'm hearing subtle things I haven't heard before.

How does it compare to the Glacier?  Looks like a nice amp the only bummer being no rechargeable battery.

 

[dryvadeum]

How does it compare to the Glacier?  Looks like a nice amp the only bummer being no rechargeable battery.

The Quickstwp is far more neutral and slightly more detailed whereas the Glacier is warm and adds a fuzzy texture to the sound. I think they complement each other well depending on what type of music you're listening to.

 

[Mad Max]

... the only bummer being no rechargeable battery.

True, that's why I bought a Tenergy 9V Li-ion rechargeable battery (and corresponding TN347 charger) for my Stepdance.

 

[cooperpwc]

I regard the user replaceable batteries to be an advantage. Buy some rechargeable 9 volts. You will never run out of power and you also will never have to send it back to the proprietor have the battery replaced.

 

[zilch0md]

Quote:

I regard the user replaceable batteries to be an advantage. Buy some rechargeable 9 volts. You will never run out of power and you also will never have to send it back to the proprietor have the battery replaced.

 
I strongly agree - I love digital cameras that accept rechargeable AA batteries, for example.  It only gets worse when the rechargeable battery is not user serviceable.

 

[cans4dessert]

I find the energizer external battery packs quite expensive, so i sought out to look for a cheaper alternative and settled for a Anker Astro3 10,000mAh battery pack that can output 12V.
Hopefully this will be enough to drive my soon-to-arrive Mad dogs!

 

[zilch0md]

Quote:

I find the energizer external battery packs quite expensive, so i sought out to look for a cheaper alternative and settled for a Anker Astro3 10,000mAh battery pack that can output 12V.
Hopefully this will be enough to drive my soon-to-arrive Mad dogs!

 
I think you've made a great choice.  I think the Anker Astro3 is a better value than the Energizer XP8000, and getting to 12V is going to make a nice improvement in dynamics and bass control.   
 
I've been using the Anker Astro3 as a clean source of 5VDC power for my USB-powered CEntrance DACport LX, getting 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
 
By the way, be careful with these battery packs that say they can power a 5V device at the same time as a higher voltage device. I fried a Sanza Clip+ by plugging it into the 5V jack of my Energizer XP8000 while simultaneously using the XP8000's 21V jack and a Willy Cable WI15 to supply 15V to my Meier Stepdance.  
 
I had a mini-to-mini interconnect running from the headphone out of the Sanza Clip+ to the Meier Stepdance input, so, visually, I had created a loop that ran from the 5V power jack of the XP8000 to the Clip+ to the Meier Stepdance and back to the XP8000, via its power cable.  I was just experimenting, but it didn't seem there should be a problem with one leg of that loop being the audio interconnect, but when I turned on the Sanza Clip+, I heard a loud pop in the headphones that were plugged into the Stepdance - and the Clip+ was toast.  I was happy the Stepdance survived with no ill effect.  (I had used the Sansa Clip+ on that same 5V jack previously, without issue.)
 
So, it's safe to power two devices simultaneously, that share no other path to each other, but don't create a loop. 

 
Mike

 

[cans4dessert]

Quote:

 
I think you've made a great choice.  I think the Anker Astro3 is a better value than the Energizer XP8000, and getting to 12V is going to make a nice improvement in dynamics and bass control.   
 
I've been using the Anker Astro3 as a clean source of 5VDC power for my USB-powered CEntrance DACport LX, getting 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
 
By the way, be careful with these battery packs that say they can power a 5V device at the same time as a higher voltage device. I fried a Sanza Clip+ by plugging it into the 5V jack of my Energizer XP8000 while simultaneously using the XP8000's 21V jack and a Willy Cable WI15 to supply 15V to my Meier Stepdance.  
 
I had a mini-to-mini interconnect running from the headphone out of the Sanza Clip+ to the Meier Stepdance input, so, visually, I had created a loop that ran from the 5V power jack of the XP8000 to the Clip+ to the Meier Stepdance and back to the XP8000, via its power cable.  I was just experimenting, but it didn't seem there should be a problem with one leg of that loop being the audio interconnect, but when I turned on the Sanza Clip+, I heard a loud pop in the headphones that were plugged into the Stepdance - and the Clip+ was toast.  I was happy the Stepdance survived with no ill effect.  (I had used the Sansa Clip+ on that same 5V jack previously, without issue.)
 
So, it's safe to power two devices simultaneously, that share no other path to each other, but don't create a loop. 

 
Mike

Sorry to hear about your Clip+. i will keep it in mind and remember not to power my entire ODAC/Quickstep setup from a single external battery source. I am currently running my portable rig as such: Galaxy S3 => ODAC => Quickstep. If i decide to power both my ODAC and Quickstep from my Astro3 using a USB dual power sharing cable, I guess it would most likely be the ODAC unit that will get fried?
 
On the side, I really wish 12V will be enough to drive my Mad Dog... I sold my AKG K702s just to get a pair of MD.

 

[zilch0md]

Quote:

Sorry to hear about your Clip+. i will keep it in mind and remember not to power my entire ODAC/Quickstep setup from a single external battery source. I am currently running my portable rig as such: Galaxy S3 => ODAC => Quickstep. If i decide to power both my ODAC and Quickstep from my Astro3 using a USB dual power sharing cable, I guess it would most likely be the ODAC unit that will get fried?
 
On the side, I really wish 12V will be enough to drive my Mad Dog... I sold my AKG K702s just to get a pair o

 
That's nice that the S3 can power your ODAC - makes for a great little stack:   Galaxy S3 => ODAC => Quickstep
 
If the ODAC already sounds "good" when powered from the Galaxy S3, with no detectable noise floor and not lacking in dynamics, there's really not much incentive, in terms of trying to solve a current problem with sound quality, to experiment with powering the ODAC from one of the Anker Astro3's 5V jacks while simultaneously powering the Quickstep from the Astro3's12V jack, but here's an easy test that would be safe to perform (at a cost of less than $10):
 
You could purchase the LaCie USB Dual Power Sharing Cable, applying the packing tape "mod" (discussed here), then use it to power the ODAC with the Astro3 while getting only data from the S3, while powering the QuickStep without the Astro3.   Try going back and forth between using the ODAC on S3 power vs. Astro3 power.  If you don't hear any improvements using the Astro3 to power the ODAC, your only incentive to proceed with powering both the ODAC and the QuickStep would be to improve battery life of the S3.  And even that incentive might not be worth the risk of creating a loop that could damage something, given that you can always take a break from listening to music to recharge your S3 on the Astro3, while out and about (away from an AC outlet).
 
Personally, the thought of trying this $10 experiment and discovering improved sound from the ODAC would frustrate me - I would then be hell bent on setting up the loop experiment - powering both the ODAC and the QuickStep with the Astro3.  I don't understand the physics of why my Sansa Clip+ got fried with my previously described XP8000 loop, but there's no guarantee that this would happen with the Astro3, your ODAC and the QuickStep.  Roll the dice, or be content.  Ignorance truly can be bliss.  "Don't fix what ain't broken," seems to be the best advice I could give you - skip the dual power cable experiment altogether, if you don't have a problem to solve.
 
Regarding your last comment, here's some information you might find frustrating (on 15V vs. 12V power for the QuickStep).
 
And quoting an eariler post:

A   9.0-Volt battery (or PSU) will yield an   8.0% increase in Maximum Output Voltage (Vpp) to the headphones, relative to an 8.4-Volt LiPo rechargeable battery.
A 12.0-Volt battery (or PSU) will yield a   57.8% increase in Maximum Output Voltage (Vpp) to the headphones, relative to an 8.4-Volt LiPo rechargeable battery.
A 12.6-Volt battery (or PSU) will yield a   69.7% increase in Maximum Output Voltage (Vpp) to the headphones, relative to an 8.4-Volt LiPo rechargeable battery.
A 13.8-Volt battery (or PSU) will yield a   95.4% increase in Maximum Output Voltage (Vpp) to the headphones, relative to an 8.4-Volt LiPo rechargeable battery.
A 15.0-Volt battery (or PSU) will yield a 123.7% increase in Maximum Output Voltage (Vpp) to the headphones, relative to an 8.4-Volt LiPo rechargeable battery.
 
So... you can more than double the output voltage to your headphones (and thus, the Watts) by using a 15-Volt supply instead of an 8.4-Volt supply!
 
And a 15-Volt supply actually increases the output voltage (and Watts) by 41.8% over a 12-Volt power supply (even though the supply voltage has only increased by 25%, from 12 to 15)!  
 

 
Note that these figures were calculated from the OPA161 datasheet - for the original Meier Stepdance - not from the OPA209 datasheet - the op-amp used in the 2Stepdance, the QuickStep, and the PCStep.  BUT:  I know the OPA209's output voltage increases with supply voltage, just the same as the OPA1611, so the ratios shown above would be applicable, if not accurate in terms of the explicit percentages shown. 
 
Keep in mind that I knew all of this when I first replied, above, that I thought you made a great choice in getting the 12V Anker Astro3 - it truly does give more bang for the buck than ordering an XP8000 and a Willy Cable WI15 + adapters.  
 
Note, too, that a 41.8% gain in output voltage (the difference between 15V supply voltage and a 12V supply voltage), translates to just a little more than 1 dB of gain.  I think you'd be hard pressed to hear a difference between 12V and 15V, especially with relatively efficient phones, like the Mad Dog.  But the difference between 8.4 V (internal rechargeable battery) and 12V (Astro3) will give you a 57.8% increase in output voltage to your headphones - just shy of a 2 dB increase - a noticeable improvement - getting you two thirds the way to the improvement had at 15V, at less than half the cost of the XP8000 setup - more bang for the buck - and a less cumbersome stack (without having to carry the WI15 cable). 
 
Lastly, the Anker Astro3 has more storage capacity than the XP8000.  I think you'll be happy with it, despite not pushing the QuickStep at its maximum permissible supply voltage.
 
Mike

 

[cans4dessert]

Quote:

 
That's nice that the S3 can power your ODAC - makes for a great little stack:   Galaxy S3 => ODAC => Quickstep
 
If the ODAC already sounds "good" when powered from the Galaxy S3, with no detectable noise floor and not lacking in dynamics, there's really not much incentive, in terms of trying to solve a current problem with sound quality, to experiment with powering the ODAC from one of the Anker Astro3's 5V jacks while simultaneously powering the Quickstep from the Astro3's12V jack, but here's an easy test that would be safe to perform (at a cost of less than $10):
 
You could purchase the LaCie USB Dual Power Sharing Cable, applying the packing tape "mod" (discussed here), then use it to power the ODAC with the Astro3 while getting only data from the S3, while powering the QuickStep without the Astro3.   Try going back and forth between using the ODAC on S3 power vs. Astro3 power.  If you don't hear any improvements using the Astro3 to power the ODAC, your only incentive to proceed with powering both the ODAC and the QuickStep would be to improve battery life of the S3.  And even that incentive might not be worth the risk of creating a loop that could damage something, given that you can always take a break from listening to music to recharge your S3 on the Astro3, while out and about (away from an AC outlet).
 
Personally, the thought of trying this $10 experiment and discovering improved sound from the ODAC would frustrate me - I would then be hell bent on setting up the loop experiment - powering both the ODAC and the QuickStep with the Astro3.  I don't understand the physics of why my Sansa Clip+ got fried with my previously described XP8000 loop, but there's no guarantee that this would happen with the Astro3, your ODAC and the QuickStep.  Roll the dice, or be content.  Ignorance truly can be bliss.  "Don't fix what ain't broken," seems to be the best advice I could give you - skip the dual power cable experiment altogether, if you don't have a problem to solve.
 
Regarding your last comment, here's some information you might find frustrating (on 15V vs. 12V power for the QuickStep).
 
And quoting an eariler post:
 
Note that these figures were calculated from the OPA161 datasheet - for the original Meier Stepdance - not from the OPA209 datasheet - the op-amp used in the 2Stepdance, the QuickStep, and the PCStep.  BUT:  I know the OPA209's output voltage increases with supply voltage, just the same as the OPA1611, so the ratios shown above would be applicable, if not accurate in terms of the explicit percentages shown. 
 
Keep in mind that I knew all of this when I first replied, above, that I thought you made a great choice in getting the 12V Anker Astro3 - it truly does give more bang for the buck than ordering an XP8000 and a Willy Cable WI15 + adapters.  
 
Note, too, that a 41.8% gain in output voltage (the difference between 15V supply voltage and a 12V supply voltage), translates to just a little more than 1 dB of gain.  I think you'd be hard pressed to hear a difference between 12V and 15V, especially with relatively efficient phones, like the Mad Dog.  But the difference between 8.4 V (internal rechargeable battery) and 12V (Astro3) will give you a 57.8% increase in output voltage to your headphones - just shy of a 2 dB increase - a noticeable improvement - getting you two thirds the way to the improvement had at 15V, at less than half the cost of the XP8000 setup - more bang for the buck - and a less cumbersome stack (without having to carry the WI15 cable). 
 
Lastly, the Anker Astro3 has more storage capacity than the XP8000.  I think you'll be happy with it, despite not pushing the QuickStep at its maximum permissible supply voltage.
 
Mike

 
thanks Mike for the useful info. I have been powering my Quickstep with a rechargeable 9V Li Po battery, and I agree that going up to 12V would be a dramatic change; 57.8% is a huge improvement. I have mainly used my Quickstep to drive HD25 and DBA-02, and I am very much content with the result. But the Mad dog that I will receive soon is my first pair of orthos and I have been hearing a lot about how orthos require a lot of power (although the MDs require less than most orthos). Also, when I checked the specs of the Quickstep, maximum power handling data isn't specifed. All i could find was the mean current uptake @ 35mA... (is this @ 9V?). I am just curious/worried as to how well the Mad dogs can be driven out of my Quickstep.
 
As for powering my ODAC from a separate power source, I am actually very happy with the sound I am getting from the s3=>ODAC=>Quickstep setup. But when i say happy, it doesn't mean that i will stop being curious =P. I think the usb power sharing cable + external battery pack is a very economic solution compared to using e.g. iFi USB power supply. But i am pretty sure if i do end up purchasing the cable, i will be very tempted not to perform the "tape mod" and see if my battery pack will be able to do all these at once:
1. charge/power my S3
2. power ODAC
3. and still transmit data from S3 => ODAC
 
Therefore, I shouldn't buy that cable.... can't afford to fry my S3

 

[zilch0md]

Quote:

 
thanks Mike for the useful info. I have been powering my Quickstep with a rechargeable 9V Li Po battery, and I agree that going up to 12V would be a dramatic change; 57.8% is a huge improvement. I have mainly used my Quickstep to drive HD25 and DBA-02, and I am very much content with the result. But the Mad dog that I will receive soon is my first pair of orthos and I have been hearing a lot about how orthos require a lot of power (although the MDs require less than most orthos). Also, when I checked the specs of the Quickstep, maximum power handling data isn't specifed. All i could find was the mean current uptake @ 35mA... (is this @ 9V?). I am just curious/worried as to how well the Mad dogs can be driven out of my Quickstep.
 
As for powering my ODAC from a separate power source, I am actually very happy with the sound I am getting from the s3=>ODAC=>Quickstep setup. But when i say happy, it doesn't mean that i will stop being curious =P. I think the usb power sharing cable + external battery pack is a very economic solution compared to using e.g. iFi USB power supply. But i am pretty sure if i do end up purchasing the cable, i will be very tempted not to perform the "tape mod" and see if my battery pack will be able to do all these at once:
1. charge/power my S3
2. power ODAC
3. and still transmit data from S3 => ODAC
 
Therefore, I shouldn't buy that cable.... can't afford to fry my S3

 
A wise choice.  Curiosity killed the Clip!  

 

[rasmushorn]

I didn't know max. output voltage was increased that much by going from a 12 to 15V PSU - now I think I am going to find myself a 15V PSU. Thanks for the info! 

 

[zilch0md]

Quote:

I didn't know max. output voltage was increased that much by going from a 12 to 15V PSU - now I think I am going to find myself a 15V PSU. Thanks for the info! 

 
I'm reluctant to celebrate the advantages of 15V, given cans4dessert having decided to go with a 12V portable solution - at a great reduction in cost and an increase in capacity, we must not forget - but not only do you get more output power (Watts) as you increase the op-amp's supply voltage, you also get a reduction in THD+Noise!  
 
@cans4dessert - You could also buy a 15V regulated PSU for use when near AC outlets, if you want.  

 
 
In a January 11, 2011 e-mail exchange I had with Jan Meier, he wrote the following (I hope I'm not wearing out his patience, with quoting this for perhaps the third time in this thread):
 
Quote:

"Yes, a good powersupply [for the Stepdance] will definitely improve on sound quality, especially when its supply voltage is so much higher than your battery voltage."

 

If you examine the datasheets for just about any op-amp used in headphone amplifiers, you can see that the op-amp's output voltage sent to the headphones increases non-linearly with (not in direct proportion to) an increase in the op-amp's supply voltage.  It just makes sense that more power in will result in more power out, unless the amplifier design incorporates some kind of internal voltage regulator (as weith the DACmini CX, that I know of, for sure.)
 
But here's a less known benefit:  When examining datasheets for op-amps, you can see that typically... 
 
THD and noise actually decrease as the supply voltage (and output voltage) increase.
 
This results in less audible distortion and a lower noise floor.  But Jan Meier's designs have ink black noise floors to begin with. (More on that topic, here.)
 
There comes a point, however, where the THD + Noise curve no longer improves with increasing supply voltage.
 
For the record, Jan Meier once posted to this thread that it's OK to use [a linear regulated power supply with] a voltage as high as 16V, despite his having labeled his power jacks with a maximum of 15V, but having more of something is not always better than having less!
 
Have a look at Figures 7 through 12 in this datasheet for the Texas Instruments OPA1611 (the Op-amp used in the Meier Audio Stepdance):   
 
Notice at the top of the page above Figure 7, it gives the temperature, voltage, and resistance used for their measurements and the following text can be found there:   Vs = ±15V     
 
That means that all of those THD+Noise charts are being presented for a situation where the Vs  (supply voltage) had a swing of ±15V.   Surely, this must be the supply voltage at which Texas Instruments has found their op-amp delivers the best performance in terms of distortion and noise.
 
Now go to the first page of the that same PDF file and look at the top left where it says "FEATURES" and you will find this text:
 
WIDE SUPPLY RANGE: ±2.25V to ±18V
 
Ask yourself, "Why did Texas Instruments present THD+Noise measurement charts taken at ±15V, when the op-amp can handle a supply voltage as high as 18V?"   Answer: The quality of the sound is best at ±15V.  
 
Going to supply voltages higher than 15V (up to 18V) increases the total Watts going to the headphones, but at the expense of best possible THD+Noise performance - not to mention other potential problems, with heat or oscillation, or ???.
 
So, just going by the OPA1611 datasheet, best possible sound quality is had at 15V.  No less, and no higher.  

 
Mike