[zilch0md]

Hi Girls Generation,
 
First, a reminder that I don't own the XP8000, but I am very familiar with the specs...
 
The XP8000 is rated at 3300 mAh (milli-amp-hours) for the 9- to 12-Volt jack that you would connect a cable to for the Stepdance.  This means that if the manufacturer's spec can be trusted, the XP8000 will last at least SIX times longer than the 520mAh iPowerUs batteries - which means the XP8000 should deliver at least 24 hours of Stepdance use on a charge.  (Don't be surprised if it's way less - we need input from a Stepdance owner to know for sure.)  But already know it's probably 8 or 10 times heavier, if not more so, than an internal 9V battery.
 
I personally don't see the iPowerUs (or any other internal battery for the Stepdance) as being at all redundant to a large, heavy, external battery pack like the XP8000.   They satisfy different purposes.  I guess if I had to be stuck with only one or the other, I would prefer the versatitlity, capacity, and higher voltage (higher SQ) of the XP8000, but I currently use both types of batteries (small internal and large external) in entirely different situations - the internal battery for when I really want to keep the weight and bulk to a minimum, and my DIY 15-Volt Lithium Polymer RC batteries for when I want SQ above all else, but don't mind the extra weight and bulk.
 
I can understand that you want to stick to a budget - a quality I admire, truly - but you might want to hang on to the iPowerUs batteries, use them for awhile, wait to get feedback from ianmedium and others on how they like the XP8000, THEN think about ordering it in addition to your internal batteries.
 
That's just my opinion - please don't feel constrained to follow my lead.  I respect that you have your own goals - possibly different from mine.
 

 
Mike

 

[Girls Generation]

Hmm, I'm leaning towards the xp8000, and Idk how logn I have to return the batteries for refund.

 

[ianmedium]

Hang on GG till I get mine and as I said you are more than welcome to meet up at a coffee shop and you can try it with your set up. I am personally going to keep my 9v batteries but that might change after seeing what my experience is with the XP. I just hope it comes with a jack that fits the stepdance as I have not heard back from Energizer to my question about that, still though if not they offer free tips for life so I can't lose!

 

[zilch0md]

 
 
Hey ianmedium!
 
The quest for 15-Volt battery packs continues!
 
I don't know what you've got up your sleeve, but I've got a challenging proposal for you:   I was just now checking out the XPAL Tip Finder web page to see if I could confirm the availability of a 3.5mm O.D. / 1.3mm I.D. tip for the XP8000, as required by the Stepdance.  I then stumbled onto their FAQ and found myself reading about the XPAL Willy Cables - special, extra-cost cables that have inline votage regulators built into them so that the XP8000 can be used with devices that require voltages higher than 12-Volts but lower than 19-Volts.
 
Guess what!  They offer an XPAL Willy Cable (model # WI15) that's made to deliver exactly 15-Volts when plugged into the XP8000's 16- to 19-Volt jack!   Saaweeeeeet! 

 
This means that you could use the XP8000 as a 15-Volt supply for the Stepdance instead of as a 12-Volt supply!
 
And better still, you will enjoy a CONSTANT 15-Volts when using the Willy Cable WI15 - even as the XP8000 battery's output at the 19-Volt jack fades down to 16-Volts with use!
 
Compare that to using the XP8000's 12-Volt jack, where the voltage will drop with use from 12-Volts down to 9-Volts.
 
You have to be a registered XP8000 user to buy it, but it only costs $7.95 + shipping (here in the States, anyway.)
 
Here's a link to the XPAL Willy Cable WI15.
 
When ordering online, just input that you're tyring to power a Toshiba Satellite M55-S1352 laptop.
 
That's one of several devices that requires exactly 15-Volts - like the Stepdance (which isn't in their Tip Finder database, of course.)
 
You will still need to get the correct sized tip (3.5mm O.D./1.3mm I.D.) that can be attached to the Willy Cable to plug into the Stepdance.
 
Are you feeling adventurous?  

 
If you order the Willy Cable WI15, please measure the output voltage with a voltmeter BEFORE you plug it into the Stepdance.  I wouldn't use it if it was anything higher than 15-Volts, and even then I have to say proceed at your own risk. 
 
Go for it! 

 
Mike
 
 

 

[monoethylene]

If you order the Willy Cable WI15, please measure the output voltage with a voltmeter BEFORE you plug it into the Stepdance.  I wouldn't use it if it was anything higher than 15-Volts, and even then I have to say proceed at your own risk. 
 
Go for it! 

 
Mike
 
 

I dont want to confuse you but the output voltage maybe higher as 15V when you measure it without any load. To get sure to be below this limit I have used a suitable resistor between the PSU and the plug.
 
 

 

[Racio]

Quote:

 
 
Hey ianmedium!
 
The quest for 15-Volt battery packs continues!
 
I don't know what you've got up your sleeve, but I've got a challenging proposal for you:   I was just now checking out the XPAL Tip Finder web page to see if I could confirm the availability of a 3.5mm O.D. / 1.3mm I.D. tip for the XP8000, as required by the Stepdance.  I then stumbled onto their FAQ and found myself reading about the XPAL Willy Cables - special, extra-cost cables that have inline votage regulators built into them so that the XP8000 can be used with devices that require voltages higher than 12-Volts but lower than 19-Volts.
 
Guess what!  They offer an XPAL Willy Cable (model # WI15) that's made to deliver exactly 15-Volts when plugged into the XP8000's 16- to 19-Volt jack!   Saaweeeeeet! 

 
This means that you could use the XP8000 as a 15-Volt supply for the Stepdance instead of as a 12-Volt supply!
 
And better still, you will enjoy a CONSTANT 15-Volts when using the Willy Cable WI15 - even as the XP8000 battery's output at the 19-Volt jack fades down to 16-Volts with use!
 
Compare that to using the XP8000's 12-Volt jack, where the voltage will drop with use from 12-Volts down to 9-Volts.
 
You have to be a registered XP8000 user to buy it, but it only costs $7.95 + shipping (here in the States, anyway.)
 
Here's a link to the XPAL Willy Cable WI15.
 
When ordering online, just input that you're tyring to power a Toshiba Satellite M55-S1352 laptop.
 
That's one of several devices that requires exactly 15-Volts - like the Stepdance (which isn't in their Tip Finder database, of course.)
 
You will still need to get the correct sized tip (3.5mm O.D./1.3mm I.D.) that can be attached to the Willy Cable to plug into the Stepdance.
 
Are you feeling adventurous?  

 
If you order the Willy Cable WI15, please measure the output voltage with a voltmeter BEFORE you plug it into the Stepdance.  I wouldn't use it if it was anything higher than 15-Volts, and even then I have to say proceed at your own risk. 
 
Go for it! 

 
Mike
 
 

Whoah! Man, you're good, thanks for the heads up Mike. I'll order these soon as well.

 

[Girls Generation]

Hmm. Well I can exchange my 2 batteries and charger for the xp8000 at no cost. I have 15 days to return the 8.4v batteries.
 
What's up with xp18000?

 

[zilch0md]

Girls Generation,
 
Quote:

Would there be a noticeable difference between using the 8.4v and the xp8000?
 
[snip]
 

I agree with Szadzik's assessment - it's a difference that can be heard with careful comparison. 
 
But I know from my own experience with comparing the Stepdance powered at 15-Volts vs. 8.4-Volts that the difference is more dramatic with recordings like those by Telarc, that make use of the full dyamic range of 16-bit CD audio, for example.  Any recording that suffers from the "Loudness" trend cannot readily reveal the improvement in headroom had when the Stepdance is powered at a higher voltage.  On the other hand, a recording that has a lot of dynamic range exhibits more "slam" during those instants when the audio signal calls for a lot of power.  
 
Basically, you're running with more Watts to the headphones when you increase the supply voltage to the Stepdance (up to the 15-Volt maximum).  You can find many explanations online of why more watts is better for any desired volume level and speaker or headphone sensitivity.
 
The End
 
Not really...  Here's more information than you probably wanted.   I can't help myself... 
 
When examining the datasheet for the Texas Instruments OPA1611 opamp used by the Stepdance, another observation I made (studying Figure 4) was that as the supply voltage to the opamp is increased, the output voltage sent to the headphones does NOT increase proportionaly - the relationship between supply voltage and output voltage is not linear - and "this is a good thing," as Martha Stewpot would say. 
 
For example, you might assume that if you doubled the supply voltage, you would get double the output voltage to the headphones (and thus double the Watts for any given current that's being supplied at any particular instant in time).  But it's actually better than double! 
 
Let's go really deep...    I created an X-Y scatter chart in Microsoft Excel, plotting the three data points provided in Figure 4 for Supply Voltage (Vs)  vs. Maximum Output Voltage (Vpp), then applied a polynomial trendline to the resulting chart and queried the equation for that trendline.  Here it is:
 
   Max. Output Voltage (Vpp) = 0.1141*x^2 - 0.2816*x + 7.0561 
 
where x is the Supply Voltage (Vs) made available to the OPA1611   (and "x^2" means "x squared," for those unfamiliar with this syntax)
 
Here are the known data points taken from Figure 4 of the OPA1611 datasheet:
 
 

Actual
Vs (supply)	Vpp (output)
2.25	7.00
5.00	8.50
15.00	28.50

 
 
Here are the same data points with some additonal data points that were calculated using the above trendline equation, and a third column, that shows the % increase in output voltage enjoyed vs. an 8.4-Volt supply.
 
 

Estimated	% Vpp Improvement
Vs (supply)	Vpp (output)	Over 8.4V
2.25	7.00	n/a
3.00	7.24	n/a
4.00	7.76	n/a
5.00	8.50	n/a
6.00	9.47	n/a
7.00	10.68	n/a
8.00	12.11	n/a
8.40	12.74	n/a
9.00	13.76	8.0
10.00	15.65	22.8
11.00	17.76	39.4
12.00	20.11	57.8
12.60	21.62	69.7
13.00	22.68	78.0
13.80	24.90	95.4
14.00	25.48	100.0
15.00	28.50	123.7

 
In English, almost...
 
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)!  
 
Joy! 

 
Mike
 
Edit:  Corrected typo and enhanced explanation of the equation:   Max. Output Voltage (Vpp) = 0.1141*x^2 - 0.2816*x + 7.0561  

 

[Girls Generation]

My brain is going to explode!

 

[zilch0md]

Hey monethylene!
 
I'm all for erring on the cautious side.  Thanks for the suggestion!
 
Can your recommend a specific type and rating of resistor and explain exactly how to deploy it?
 
Thanks,
 
Mike

 

[HeadphoneAddict]

Interesting - all my impressions of the Stepdance were with the OPA1611 prototype (and AD8610 which was a little more laid back sounding) using my 15v regulated PSU, since the 9v battery operation wasn't implemented yet.  So was getting full/max power output.  I haven't actually heard one running at 9v.

 

[monoethylene]

Quote:

Hey monethylene!
 
I'm all for erring on the cautious side.  Thanks for the suggestion!
 
Can your recommend a specific type and rating of resistor and explain exactly how to deploy it?
 
Thanks,
 
Mike

The background was that I found a standard PSU at my work and fortunately with a plug which fits in the Stepdance. After measuring the output voltage I saw that it was higher as the printed 15V (without any load).
 
To get sure not to destroy sth. I ve just added a normal voltage divider and I ve chosen the resistors to 100 Ohm and 1000 Ohm. The input impedance, IMO the load of the Stepdance is 55/16 kOhm. Finally I ve cutted the cable and with some heatshrink and soldering I putted the resistors inside.
 

 

 

[ianmedium]

Wow, not sure if I am that adventurous quite yet but will give it all some thought, I am just excited to try it all with the 12 volts. I am hoping that one of the supplied tips does indeed fit the stepdance from what little research I have done it does seem that Jan has put a fairely standard spec socket on the amp so hopefully one of the tips that comes with the XP will fit, otherwise it will be a two week wait for energizer to send me one once I register the product keep your fingers crossed folks.

As an aside I decided to see what I had around that would fit so tried the power cord for my powerex stealth battery charger and it fit perfectly (I did not plug it into a power supply obviously as all I wanted to do was make sure of the fit as the center pin on the socket on the am looked slightly off center, no problems thankfully.

I have been thinking about the 9 volt, I know Jan says keep a battery in when using an external power source to keep the door on but I think I will just take it out and use a bit of black electrical tape so keep the door shut.

You guys rock with your technical knowledge, makes me wish I had not zoned out thinking about Thoreau's writings whilst in science class all those many years ago!

 

[monoethylene]

After reading a little bit more in this thread I ask myself why it is such a subject to find a right power supply? Is it just to have more time when powered external or are there any other reasons except the factor of DIY? As far as I know has the Stepdance a very good power regulation inside as well as a good filter. So, is it worth to spend more money in external accupacs and so on to really improve the sound?

 

[ianmedium]

 
Quote:

After reading a little bit more in this thread I ask myself why it is such a subject to find a right power supply? Is it just to have more time when powered external or are there any other reasons except the factor of DIY? As far as I know has the Stepdance a very good power regulation inside as well as a good filter. So, is it worth to spend more money in external accupacs and so on to really improve the sound?

I will let you know tomorrow hopefully about the sound improvements if any. I do know that when I used a true 9volt battery as opposed to my 8.4 volt rechargeable I did notice a subtle difference in sound quality with the higher power. That took the form of a slightly smoother organic sound, a little more ease and head room if you will. I have not found the length of battery life to have been a problem with me for this amp so this is more an experiment in sound quality improvements, hopefully the mail man will have been kind to me tomorrow!