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Guitiar Negative Impedance Converter
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Inventor
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PostPosted: Sat Sep 27, 2008 8:42 am    Post subject: Guitiar Negative Impedance Converter
Subject description: Just an idea
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Hi, I came up with an idea for a guitar pedal box. It is very simple, you build a negative impedance converter and in place of one of the resistors you put a duplicate of your guitar's pickup. In my paper calculations, the negative impedance can be made to cancel out the source impedance of your pickup, thereby leaving a flat pickup response. What do you think of this idea? Will it work? Has it been done before? Stoopid or kewl?
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Uncle Krunkus
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PostPosted: Sat Sep 27, 2008 8:47 am    Post subject: Reply with quote  Mark this post and the followings unread

What's a negative impedance converter?
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blue hell
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PostPosted: Sat Sep 27, 2008 10:21 am    Post subject: Re: Guitiar Negative Impedance Converter
Subject description: Just an idea
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Inventor wrote:
In my paper calculations, the negative impedance can be made to cancel out the source impedance of your pickup, thereby leaving a flat pickup response.


Would it not oscillate easily?

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Jan
also .. could someone please turn down the thermostat a bit.
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blue hell
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PostPosted: Sat Sep 27, 2008 10:25 am    Post subject: Reply with quote  Mark this post and the followings unread

Uncle Krunkus wrote:
What's a negative impedance converter?


Some info on it : http://en.wikipedia.org/wiki/Negative_resistance - impedance would be generalized resistance, adding an "imaginary part" to it - making the numbers complex.

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Jan
also .. could someone please turn down the thermostat a bit.
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Stream Operator


Joined: Oct 13, 2007
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Location: near Austin, Tx, USA
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PostPosted: Sat Sep 27, 2008 11:29 am    Post subject: Reply with quote  Mark this post and the followings unread

Aye, this be the beastie:

http://en.wikipedia.org/wiki/Negative_impedance_converter

You can replace either R1 or R3 with the pickup. In my calculations I put the pickup in place of R3, though that might not be the correct place. R1 might be better.

It might be prone to oscillations, yes. That could be it's Achilles heel. It might be possible to dampen those oscillations. Perhaps the tone control knob would dampen them.

The beauty of using a pickup to cancel a pickup's source impedance is that all impedance characteristics, including the distributed nature of the impedance, could perhaps be accounted for automatically. Or not, I'm not certain but that's my guess.

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