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Speaker amps for headphones - Page 49

post #721 of 2754

^ lol

post #722 of 2754
Quote:
Originally Posted by brunk View Post

^ lol

 

+1

 

Love your sense of humor Gary.

post #723 of 2754
Quote:
Originally Posted by Gary in MD View Post

Mike:

 

If I understand things correctly (not a given,but we'll try this anyway), if all we are doing is driving headphones with the amp it will use very little power, and the batteries will last a lot longer.  The LCD-3s, relatively inefficient planar headphones, take 1mW to get to 91 dBs.  Even running through the resistor box, I never have the volume past 9:30 on the dial, and I don't think it takes much power for its overhead and housekeeping (the thing is never even warm) so I doubt the Millenia is ever pulling >2 amps,  In fact, I'd be surprised if it was pulling even 1.

I agree,

I would be surprised if that amp was drawing anywhere 1 amp to drive a wee little pair of headphones! wink_face.gif

 

BTW, fuses are for overcurrent protection, not overvoltage protection.

I'd stick to 24 Vdc or less battery packs (which is effectively a 27 Vc battery pack) and wouldn't count on fuses to cover your butt!

post #724 of 2754

Yeah, in my case at least, that would take some really big fuses...

 

Okay, enough bad comedy, let's get serious here people...

post #725 of 2754

Hey Flysweep,

 


Quote:
Originally Posted by FlySweep View Post

^ Mike, you're my hero. ^  Really appreciate the info.. I'll definitely pursue this option.  The battery pack is doable, but I'd like to keep the desktop space as clean as possible.. so these batteries will be excellent.

 

 

 

My post on using six 3.7V AA Li-Ion and two dummy batteries for 25.2V inside the MG3's battery compartment (Click to show)

 

Quote:

Originally Posted by zilch0md View Post

Here's a way to operate the MG3 at  25.2V while using only AA-sized batteries, internally:

 

If you want to get closer to the MG3's maximum permissible 27V, while using AA-sized batteries internally, you might consider researching 3.7V AA-sized Li-Ion "14500" batteries, similar to these made by Tenergy (a well-respected brand):

 

 

http://www.all-battery.com/6pcsLi-IonFlatTop14500_3.7V_800mAh_AA_RechargeableBatteries-39172.aspx

 

 

 

And here's a smart charger that can charge "14500" Li-Ion batteries, but it only does four at a time:

 

 

http://www.batteryjunction.com/smx-intellicharge-i4.html

 

 

Li-Ion 14500 batteries are the exact same size as 1.5V AA Alkalines, but when fully charged, they will measure 4.2V each.  (3.7V is their nominal rating.)

 

The MG3 battery compartment holds 8 AA cells and it connects them serially (end-to-end), so if you were to load it up with eight of these Li-Ion 14500 batteries, you would get 33.6V, total - but we must not go past 27V. 

 

Solution:  Use 6 of the Li-Ion 14500 batteries shown at the link above (or their equivalent), for a total of 25.2V (the same, fully-charged voltage I'll be getting with the 6-Cell LiPo pack I've ordered).  

 

But how do you use six AA's in a battery compartment made for eight AA's?  Add two fake AA batteries!

 

http://www.ebay.com/itm/2-pcs-Pack-Dummy-Battery-AA-Conduct-Conductor-Electric-Current-Ultracell-plus-/271250525019

 

So, it's possible to run the MG3 at 25.2V, using internal AA batteries.

 

I might try this later on, but for now, I'll stick with the external LiPo pack approach.

 

Mike

 

 

 

If you're still considering this, it occurred to me today that we should ask Jan Plummer if the MG3 can handle 25.2V coming from its battery compartment.  It's possible, though I think unlikely, that the MG3 can only handle more than 12V when it's coming from the DC power connector.  I'll send him an e-mail and find out.

 

Thanks,

 

Mike

post #726 of 2754
Quote:
Originally Posted by zilch0md View Post

Hey Flysweep,

 


 

If you're still considering this, it occurred to me today that we should ask Jan Plummer if the MG3 can handle 25.2V coming from its battery compartment.  It's possible, though I think unlikely, that the MG3 can only handle more than 12V when it's coming from the DC power connector.  I'll send him an e-mail and find out.

 

Thanks,

 

Mike

I don't think Jan would mind my posting his response to my asking about the internal battery idea that was presented:

 

"That will work, however there is no over voltage protection for the internal battery pack. As long as the voltage is kept below 30v the amp will not be damaged. It is nearly impossible even with 6 x 3.7 = 22.2v even if they are intermittently at 6x 4 =24v. 

We won't be responsible for damage so the experimenter should know what he/she is doing. "
post #727 of 2754

Thanks Stew!

 

So there is a difference in that the internal battery compartment isn't fused.  Well, at least it's possible to test the voltages of each battery before loading them.  

 

If the 3.7V AA batteries I found (above) are true Li-Ion batteries, they will come to 4.2V per cell when fully charged, for a six-cell total of 25.2V - still quite a ways from the maximum permissible 27.5V.

 

I'll pretend I didn't see "30V" as the new maximum (per your quote, above).  A 30V maximum would allow the use of seven 4.2V AA batteries, for a total of 29.4V, but that's just cutting it too closely.

 

Thanks,

 

Mike


Edited by zilch0md - 8/19/13 at 11:59am
post #728 of 2754
Quote:
Originally Posted by zilch0md View Post

Thanks Stew!

 

So there is a difference in that the internal battery compartment isn't fused.  Well, at least it's possible to test the voltages of each battery before loading them.  

 

If the 3.7V AA batteries I found (above) are true Li-Ion batteries, they will come to 4.2V per cell when fully charged, for a six-cell total of 25.2V - still quite a ways from the maximum permissible 27.5V.

 

I'll pretend I didn't see "30V" as the new maximum (per your quote, above).  A 30V maximum would allow the use of seven 4.2V AA batteries, for a total of 29.4V, but that's just cutting it too closely.

 

Thanks,

 

Mike

Testing the voltages of each battery before installing them......you are thinking of everything!smile.gif

 

Stew

post #729 of 2754

Stew,

 

You wouldn't believe the ritual I go through for my Stepdance 4-cell LiPo packs...

 

I have to charge them to 16.8V, then use a discharge feature of my balance charger to bring them down to 15.0V, before I can use them with the Stepdance.  

 

IMG_6575_1024x768_12.6-Volt-2200mAh_LiPo_for_Meier_Stepdance_with_Sony_PCM-M10.jpg

 

15.0V LiPo pack is at top left, Meier Stepdance amp at top right, and a Sony PCM-M10 96/24-capable Linear PCM recorder is at bottom center (used as my DAP).

 

 

IMG_6542-tweaked-x768s.jpg

 

 

A screenshot from this PDF showing how I routinely confirm successful discharge to 15.0V, prior to using the LiPo packs with my Stepdance.

 

 

 

Those 4-Cell LiPo packs are a lot lighter and smaller (for walking about with the case and shoulder strap) than using the Energizer XP8000 lithium battery pack + inline voltage regulator, as I do with an iBasso PB2 Pelican (balanced amp) in my "transportable" rig. 

 

 

IMG_8176_iBasso_PB2_Powered_by_XP8000_With_Willy_Cable_WI16_900x800.jpeg

 

 

I have a "thing" for batteries.  As HappyCamper called it... "battery love."

 

Battery power is clean-sounding power!

 

biggrin.gif

 

Mike

post #730 of 2754
Quote:
Originally Posted by zilch0md View Post

Stew,

 

You wouldn't believe the ritual I go through for my Stepdance 4-cell LiPo packs...

 

I have to charge them to 16.8V, then use a discharge feature of my balance charger to bring them down to 15.0V, before I can use them with the Stepdance.  

 

IMG_6575_1024x768_12.6-Volt-2200mAh_LiPo_for_Meier_Stepdance_with_Sony_PCM-M10.jpg

 

15.0V LiPo pack is at top left, Meier Stepdance amp at top right, and a Sony PCM-M10 96/24-capable Linear PCM recorder is at bottom center (used as my DAP).

 

 

IMG_6542-tweaked-x768s.jpg

 

 

A screenshot from this PDF showing how I routinely confirm successful discharge to 15.0V, prior to using the LiPo packs with my Stepdance.

 

 

 

Those 4-Cell LiPo packs are a lot lighter and smaller (for walking about with the case and shoulder strap) than using the Energizer XP8000 lithium battery pack + inline voltage regulator, as I do with an iBasso PB2 Pelican (balanced amp) in my "transportable" rig. 

 

 

IMG_8176_iBasso_PB2_Powered_by_XP8000_With_Willy_Cable_WI16_900x800.jpeg

 

 

I have a "thing" for batteries.  As HappyCamper called it... "battery love."

 

Battery power is clean-sounding power!

 

biggrin.gif

 

Mike

 

 

 

 

Yeah, the Millenia on 12 volt power is definitely 'cleaner' sounding (translated.....more transparent). I am wondering if I am preferring a little distortion thrown into the mix with the ac. OR, I whether getting closer to 24 volts of battery power would give the best of both worlds....fuller AND clearer sound. Maybe we'll find out sometime. 

post #731 of 2754

Mike.. what about going with the Anker 12v power pack that we discussed a while back on the QUICKSTEP thread?  24v would be nice.. but I doubt I'll need all that power since much will probably be attenuated by the resistor box.. and I'll just be feeding the HD800 (and a relatively efficient ortho, the Paradox).

post #732 of 2754

Flysweep:

 

I looked at various 12-24v battery packs like the Anker, and Jan didn't think they would work very well.  They really aren't designed for audio purposes, and have internal circuitry that adds noise.  Unfortunately we're better off with car batteries (or at least scooter batteries...).

post #733 of 2754
Quote:
Originally Posted by FlySweep View Post

Mike.. what about going with the Anker 12v power pack that we discussed a while back on the QUICKSTEP thread?  24v would be nice.. but I doubt I'll need all that power since much will probably be attenuated by the resistor box.. and I'll just be feeding the HD800 (and a relatively efficient ortho, the Paradox).

 

Quote:
Originally Posted by Gary in MD View Post

Flysweep:

 

I looked at various 12-24v battery packs like the Anker, and Jan didn't think they would work very well.  They really aren't designed for audio purposes, and have internal circuitry that adds noise.  Unfortunately we're better off with car batteries (or at least scooter batteries...).

 

Therein lies the beauty of actually testing rather than theorizing.  My idea of using AA lithiums inside the MG3 is untested, but I've been using the Energizer XP8000 and the Anker Astro3 Lithium-Ion packs in multiple audio applications, to power amps and DACs, for a couple of years now, all without hearing noise of any kind from either product.  I will be testing both of them with the MG3, to be sure.  

 

The XP8000 (and its larger sibling, the XP18000) have multiple jacks from which various voltages can be pulled.  I am fairly confident that neither of these packs contain switch-mode circuitry to achieve the various voltages, as their is A) no audible hum coming from these packs when they are operating and B) the voltages measured at these jacks fall as the pack is used.  I may be wrong, but this leads me to believe that the different voltages are achieved strictly through various combinations of serial vs. parallel arrangement of the packs' individual 4.2V cells.  

 

Here's an annotated picture of the working end of an XP8000:

 

 

Measurements of the Energizer XP8000

 

Based on measured voltages when new and fully charged and the fact Energizer literature indicates they use LiPo chemistry (which has to be be 4.2V per cell), I think the XP8000 and XP18000 each have five cells (for a maximum possible voltage of 21.0V), where the Anker Astro3 has only three cells, for a maximum output of 12.6 Volts.

 

I'm pretty sure that the default cable that are included with either the XP8000 or XP18000 are already terminated with exactly the right size barrel connector required for use with the MG3, so no adapter will be necessary to get pretty close to 21.0V into the MG3's power jack when the pack is new and fully charged.  So, yes, I will be testing this with the MG3.

 

The Anker Astro3 isn't as appealing to me, because it's limited to 12.5V when new and fully charged.

 

But here are some photos evidencing how I've been using them both, successfully, without noise problems - as have at least a dozen people who follow the Meier Stepdance thread - all without complaint of noise.

 

 

 

Above, a CEntrance DACport (note the volume control that's not found on the DACport LX) is being powered by an Anker Astro3 (no noise).  Only data is coming from the laptop port.

 

 

 

Above, an Anker Astro3 is powering a Centrance DACport LX with clean 5V DC, while only data is coming from the laptop port.   An Energizer XP8000 is simultaneously powering a Meier Stepdance amp, via an inline 15.0V regulator (which I strongly suspect uses switch-mode technology, but many Stepdance owners report they still have the inky-black noise floor for which the Stepdance is renowned) - even though you can hear a feint buzzing sound coming from the inline voltage regulator itself when you put your ear next to it.)  

 

 

LaCie USB DualPower Sharing Cable for Rikiki - closeup of "tape" mod

 

LaCie USB DualPower Sharing Cable for Rikiki

 

Anker Astro3 10,000 mAh LiPo batery pack supplying "clean" 5VDC power to the DACport LX, with only data coming from the laptop, having taped the 4th pin of that USB connector. 2 amps of clean 5V power!

 

Above, the Anker Astro3 is again supplying power to the DACport, but this time, it's going to a Burson Soloist (out of frame).  No noise issues.

 

 

 

 

1000

 

Above, a close-up of the one of my inline voltage regulators (this one switches between 16V or 19V, where the other one I have is fixed at 15V).  They both make a humming noise that can't be heard in the headphones, only when you place your ear next to them.  For the MG3, I will not be using either of these inline voltage regulators.  I'll be connecting to the blue 21.0V port, directly.

 

XPAL Willy Cable WI16 - perfect for connecting the Energizer XP8000 to an iBasso PB2 - for a constant 16V supply voltage.

 

IMG_8176_iBasso_PB2_Powered_by_XP8000_With_Willy_Cable_WI16_900x800.jpeg

 

I've never heard any noise in the PB2 from using this setup (with the WI16 inline regulator), and I would venture I've only put about three hours total on the PB2's internal 12.6V LiPo pack.  I use it exclusively with the XP8000 and 16V regulator - hundreds of hours, no noise issues.

 

 

 

 

1000

 

This is where it all started - tests I did with the Stepdance to come up with a 15V portable solution.  No noise - every bit as quiet as my 4-cell LiPo RC packs.

 

 

1000

 

 

Travel Rig as stored when carrying

 

Above, my "travel rig" before I started using the Stepdance strictly as part of my "walk about rig."  I now carry the balanced output iBasso PB2 in my "travel rig".
 

 

Travel rig ready for use

 

Travel rig ready for use - everything powered by the XP8000 - no noise.

 

I've even powered my DACmini CX (desktop DAC/amp combo) using the XP8000 - no noise (sorry, no picture, either!)

 

biggrin.gif

 

I'm still open to the possibility that the MG3 might hear noise coming from the XP8000, but if not, I think I'll still prefer to use the 3600 mAh 6-cell LiPo pack I discussed in a previous post, because I have more control over what's happening with those RC packs - with the ability to measure voltage of each cell in a pack, using an audible alarm to detect when one or more cells reaches 3.0V, true balance charging of the pack for longer life and reliability, without paying for all the extras that come with an XP8000 or XP18000.   The XP8000 takes away all the fun, but I have to admit, it's far more convenient.  

 

Mike

post #734 of 2754

Mike:

 

I'll be real interested to see how the Energizer XPs sound with the Millenia, since I'm into convenience... regular_smile%20.gif

post #735 of 2754

Stew (and FlySweep),

 

Quote:
Originally Posted by SMG52 View Post

I don't think Jan would mind my posting his response to my asking about the internal battery idea that was presented:

 

"That will work, however there is no over voltage protection for the internal battery pack. As long as the voltage is kept below 30v the amp will not be damaged. It is nearly impossible even with 6 x 3.7 = 22.2v even if they are intermittently at 6x 4 =24v. We won't be responsible for damage so the experimenter should know what he/she is doing. "

 

Jan has replied to my e-mail with a response very similar to what you've posted, above, adding that the 4.2V AA Lithiums might not be able to supply enough current to take advantage of the 25.2V worth of voltage six of them could supply. He said they might also be noisy in and of themselves (paraphrasing).

 

So... testing is our only way to know for sure, but when you consider that the XP8000 is a 5-cell LiPo pack that can power the likes of laptops, and that the 6-cell RC LiPo pack I've ordered can actually deliver 152 Amps, continuously,  we might be OK with the AA 4.2V cells, in terms of providing sufficient current.  

 

Again, Jan has pointed out, very reasonably, that he can't be responsible for damage caused by such experiments. 

 

I will be testing the 21.0V XP8000 and the 25.2V LiPo pack when my MG3 arrives.

 

Mike 

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