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Speaker amps for headphones - Page 113

post #1681 of 2542
Quote:
Originally Posted by ALRAINBOW View Post

I think you misunderstood me. They will explode or puff from that kind of use

But what it might do is not charge anymore. This is what I meant.

Also go the an Rc website for battery info. Helifreak.com

 



I'm fighting back the impulse to say this might look interesting if it happened in mid-air!
Ooops, I said it. LOL.

Just don't stand underneath if it does happen.
post #1682 of 2542
Quote:
Originally Posted by ALRAINBOW View Post

I think you misunderstood me. They will explode or puff from that kind of use
But what it might do is not charge anymore. This is what I meant.
Also go the an Rc website for battery info. Helifreak.com

 

I understand you, clearly, but across three years of using RC batteries for audio purposes (links can be found here at Head-Fi to evidence this), I've been taking multiple brands and sizes of LiPo batteries down to 3.4V without any evidence of swelling, failure to charge, puffing, explosions, etc.  That's my empirical experience with these batteries, but I am certainly willing to concede that I may have been "getting away with murder," so to speak.  So, I will look into it, for sure.  It won't hurt my run time all that badly to stop taking them below 3.6V, in any case.

 

Thanks!

 

Mike

post #1683 of 2542
Quote:
Originally Posted by robrob View Post
 

Here's the alpha release of my headphone network calculator: http://robrobinette.com/images/Audio/Headphone_Resistor_Network_Calculator.xls

 

It's an Office spreadsheet created with Libreoffice but Microsoft compatible.

 

Using my HE-500's 32 ohm impedance and 8 ohms for my amp's load impedance it came up with R2 of 6 ohms and R3 of 2 using "Dual Resistor Network A."

 

Those resistors give an amp load of 7.9 ohms, headphone input impedance of 1.3 and amp attenuation of 4.2 times more than the headphones alone.

 

I'm very open to corrections and suggestions. Please don't actually build a network using it until the gurus look it over.

 

Rob

The calculations look pretty good! A few things to improve it though. Label the "Resistor Networks" as what usage scenario it will be for each one. Such as, "For Powerful SS Amp", "For Tube Amp" etc. Second, it would be nice to have the amp's output impedance as an optional calculation for sake of completeness. Third "Headphone input impedance" should be "Amplifier output impedance". Fourth, include the wattage value of the resistor, like 5 or 10 watts, and also wirewound/cement/metal film etc. Lastly, a bunch of pictures aren't loading for me for some reason.

 

Great work Rob :D

post #1684 of 2542
You are welcome mike
post #1685 of 2542
Quote:
 Label the "Resistor Networks" as what usage scenario it will be for each one. Such as, "For Powerful SS Amp", "For Tube Amp" etc

 

Can you give me suggested names (uses) for the 4 networks?

post #1686 of 2542
Quote:
Originally Posted by Chris J View Post
 
Quote:
Originally Posted by ALRAINBOW View Post

I think you misunderstood me. They will explode or puff from that kind of use

But what it might do is not charge anymore. This is what I meant.

Also go the an Rc website for battery info. Helifreak.com

 



I'm fighting back the impulse to say this might look interesting if it happened in mid-air!
Ooops, I said it. LOL.

Just don't stand underneath if it does happen.


Sort of makes me wonder how Amazon thinks they are going to fly billions of packages around the US using battery-powered, autonomous rotary craft.

post #1687 of 2542
Quote:
Originally Posted by robrob View Post
 

 

Can you give me suggested names (uses) for the 4 networks?


I suppose John, Paul, George and Ringo would not be appropriate?

post #1688 of 2542
Wow did you see that last night. Did you here what he said it's a done deal just the legal part.

I have a uav about that size. With a go pro. Those blades are not fun, and how about it drops a package of 5 pounds on your head. The technology is there , I wonder when the jetsons will be back lol
post #1689 of 2542
Did you see the photo of the RCheli guy in Brooklyn ny ?
post #1690 of 2542
Quote:
Originally Posted by robrob View Post
 

 

Can you give me suggested names (uses) for the 4 networks?

 

Um,

 

Fred,

Barnie,

Wilma,

Betty?

 

Or,

Number 1:    not sure I see the point of this one! :rolleyes:

I suppose if you drive the headphones directly off the amp output, then with a tube amp, it MAY sound better if the tube amp is loaded down to a typical speaker impedance

 

Number 2:    my favourite  :tongue_smile:

versatile

Number 3:    kinda like a vintage receiver  :confused_face_2:

doesn't really do much unless R2 is 100 or 200 Ohms or some other high value

 

Number 4:    too complicated for it's own good. :evil: 

but it impresses the neighbours and may even impress the chicks, well, maybe the geeky ones!


Edited by Chris J - 12/2/13 at 3:33pm
post #1691 of 2542

I've added most of the suggested changes except changing attenuation and adding resistor watt calculations.

 

Here's the latest Headphone Resistor Network Calculator: http://robrobinette.com/images/Audio/Headphone_Resistor_Network_Calculator.xls

post #1692 of 2542
Quote:
Originally Posted by ALRAINBOW View Post

You are welcome mike

 

I really do appreciate your bringing this to my attention.  I'd like the batteries to last as long as possible before having to buy new ones and I don't want any fires, either.  :beerchug:

post #1693 of 2542
For your use you should about 300 hundred charges before it will go dead faster. One last thing always be around the battery when charging , like don't go to bed lol
Also at what rate do you charge a good rule of thumb is two times the am rating . So a 5000 ma is 5amps and it will be. Charged in 1 hour or so.
The batteries we are using are the same in our cell phones , but much larger .

Al D
post #1694 of 2542
Quote:
Originally Posted by ALRAINBOW View Post

For your use you should about 300 hundred charges before it will go dead faster. One last thing always be around the battery when charging , like don't go to bed lol
Also at what rate do you charge a good rule of thumb is two times the am rating . So a 5000 ma is 5amps and it will be. Charged in 1 hour or so.
The batteries we are using are the same in our cell phones , but much larger .

Al D

I thought you should you be charging at half the rate...say 2.5a or preferably less? :confused: Heat and such...

post #1695 of 2542
No not really. . On the battery there is a c rating this is the max charge rate times the amp of the battery . Let's say the battery you have says 5c. Then you could charge the battery at 5 time the battery rating. Now I would never do that but it it what it says. Then there a discharge rate. Not needed for you guys and the last is the burst . Let's say I am doing some hard three dee moves the amps are going really high . So for this you need better batteries .

Al D
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