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Tiniest Portable amp I can build

May 4, 2011 at 11:40 PM Post #31 of 91


Quote:
high_q said:
^your transformer is not an amp.  It has no gain.  What does it do again?? Its useless object in a can that produces placebo.  Nice try nik, but you neglicted to mention its not an amp, and its a piece of crap in a tin box. You neglicted a no brainer key feature of an amp.  Its called gain...  Lets see... there is no power source.... ummm were talkin about amps here?  How is that transforer(look at the definition again) doing what I was looking for??  Do some research before you slap together some nonsensical box you think its revolutionary.  Umm there is a reason why it doesn't exist in place of an amp.  You got quite an imagination for coming up with ideas. 
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The quality of an amplifier can be characterized by a number of specifications, listed below.  What does it do again?  Pay attention to the power ratio.

[edit]From wiki:

Gain

The gain of an amplifier is the ratio of output to input power or amplitude, and is usually measured in decibels. (When measured in decibels it islogarithmically related to the power ratio: G(dB)=10 log(Pout /(Pin)). RF amplifiers are often specified in terms of the maximum power gainobtainable, while the voltage gain of audio amplifiers and instrumentation amplifiers will be more often specified (since the amplifier's input impedance will often be much higher than the source impedance, and the load impedance higher than the amplifier's output impedance).

  1. Example: an audio amplifier with a gain given as 20 dB will have a voltage gain of ten (but a power gain of 100 would only occur in the unlikely event the input and output impedances were identical).

If two equivalent amplifiers are being compared, the amplifier with higher gain settings would be more sensitive as it would take less input signal to produce a given amount of power.[1]
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It seems you are entitled to an appology for my posts in this thread. 
 
Im sorry that you dont understand what I posted here. A couple people who have never even claimed to be engineering students or engineers seem to get it. 
 
Quote:
high_q said:
I guess EE school wasn't total waste of time.  :)
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May 4, 2011 at 11:42 PM Post #32 of 91
^Well as an EE, I get that its not an amp.
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  And what you have in the tin box is useless.  Get that garbage out of my thread.
 
May 4, 2011 at 11:53 PM Post #33 of 91
No, it serves a perfectly useful purpose. 
 
it provides a voltage stepdown (voltage gain of approximately -21db with the parts I used) and a current step up of about +21db. It appears as a high impedance load to the source, and provides a low output impedance to the headphones.
 
May 4, 2011 at 11:56 PM Post #34 of 91


Quote:
high_q said:
Did you end up with T3 and why?  
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Still waiting for Craig's balanced cable so I can try to Toucan balanced.  That's my last hope.  I think the Toucan might make a big difference that would be worth the size/weight out and about.  If not, it goes too.  The RSA Shadow and Pico Slim are both incredible amps that vastly exceed the T3D in the quiet of my apartment.  But outside, on the street, in the subway, on the bus, pretty much anywhere I'd use my iems, the ambient noise and the noise from my own bodily movement will cancel out all of the $200 price differences between these amps.  And in the quiet of my apartment, the DacPort out of my MacBookPro through amarra or audirvana blows them all away handily for the same price.
 
 
May 4, 2011 at 11:57 PM Post #35 of 91
Its a transformer, yes.  I know what those are.  I know what they do.  I'm looking for an amp sorry.  I want gain.  Its useless to me.
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  And for everybody.  because it for DAP source.  Its not like I have a tube amp to lower the output impedance to drive IEMs.  And you know what I still need the amp, because thats precisely what I need, to amp.  It has gain.
 
May 5, 2011 at 12:06 AM Post #37 of 91
I was questioning why you needed to make such an interesting device *look* like an amp with the use of unnecessary switches and LEDs, but I guess that question has been answered. I don't pretend to be an EE (all I took was basic E&M) but I know enough about audio (and nikongod) to know that his device works.
 
I've never had to go past half volume on my PDAPs for any of my IEMs to get to uncomfortably loud even for street usage, and even with the most inefficient IEMs (RE262, Phonak 122s). I happen to like my hearing and treasure it. To each his own, I guess.
 
May 5, 2011 at 12:16 AM Post #38 of 91
[size=small]Great idea.  CR2477 is 1000mAh.  Its great capcity for size and 3v eac[/size][size=small]h[/size]
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  I would like to get Fred's board and build it with watch battery, stack a bunch of them, or side by size wire them series depending how I implement the casing.  
 
Quote:
armaegis said:
Maybe a stack of watch batteries?

 
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May 5, 2011 at 12:38 AM Post #42 of 91
yes I do.  Then, you want me to get an amp that has no gain?
 
Quote:
limpidglitch said:
You do not want gain.
 
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@James.  Size of a zippo?  Any pics?
 
 
@Nikongod, I'll just use my volume adjuster on my DAP than add a transformer.  It just seams a bit easier.
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May 5, 2011 at 12:41 AM Post #43 of 91
voltage gain of 1. you only attenuate about 30db in software this way. 
 
With voltage gain of 1/11~=-21db you only attenuate 10db in software. You only have so much signal, it seems a shame to waste so much of it. 
 
May 5, 2011 at 12:59 AM Post #44 of 91


Quote:
jamesmcprogger said:
some time ago I saw a thread with an amp inside a zippo. are you guys up to something even smaller?
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The Zippo CMoy was not self-contained, unfortunately - it was powered via USB, and USB power only IIRC. It should be some pages back in the "Post your builds" thread.
 
 
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