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[Amps] Johnson 226-3 Roller Inductor

To: "AMPS" <>
Subject: [Amps] Johnson 226-3 Roller Inductor
From: "Bob Maser" <>
Date: Thu, 1 Nov 2007 17:36:21 -0400
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I have a question on how to connect the 226-3 roller inductor into an 
amplifier tank circuit.  I am currently using one of these roller inductors 
in a homebrew 3CX3000 amp and another one in a Henry 4K Ultra.  The one in 
the Henry is the original one used by Henry.  On the Henry, the non grounded 
side of C1 is connected to the wide spaced end of the coil and C2 is 
connected to the rail that has the (wiper)traveler on it and this makes 
contact with the turns of the coil as it is rotated.  The homebrew 3X3 is 
wired up exactly the same.  The difference is on the Henry the top rail is 
also connected to the narrow spaced end of the coil with a strap but on my 
HB amp it doesn't have this connection.  My question: does this connection 
between the far end of the coil and the rail  short out the unused part of 
the coil? I think I already know the answer(yes).  What benefit does this 
provide?  Is it an absolute necessity? I don't use the amp above 20M.   If 
so I have been using the 3X3 amp unshorted out for 4 years.  Maybe this is 
why everytime I tune up the amp my garage door opener needs to be reset in 
order to work.


Bob Maser  W6TR 

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