What's the deal with Broskie's iPod buddy? - diyAudio
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Old 21st July 2006, 03:06 AM   #1
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Default What's the deal with Broskie's iPod buddy?

I don't understand the reasoning behind Broskie's "normal" Aikido low-Z headphone amp:

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and his "iPod buddy" version:

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The latter version features higher gain in the front stage and a feedback loop in order to implement it. Why would you need higher gain when iPod's and MP3 players can already drive headphones directly?
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Old 21st July 2006, 04:46 AM   #2
poobah is offline poobah  United States
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The circuits have much different input impedances.

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Old 21st July 2006, 09:33 PM   #3
moamps is offline moamps  Croatia
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Default Re: What's the deal with Broskie's iPod buddy?

Quote:
Originally posted by leadbelly
The latter version features higher gain in the front stage and a feedback loop in order to implement it. Why would you need higher gain when iPod's and MP3 players can already drive headphones directly?
Hi:

The use of higher open loop gain and NFB will result in smaller output impedance than in a non-NFB design, which is important when small-impedance phones need to be driven. Also, in this case, the application of NFB lowers the headphone amplifier gain to an acceptable value.

Regards,
Milan
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