[Amps] Hallicrafters HT-41

Jim Thomson jim.thom at telus.net
Mon Nov 9 06:20:06 EST 2015


Date: Sun, 8 Nov 2015 06:38:48 +0000
From: "Fuqua, Bill L" <wlfuqu00 at uky.edu>
To: James Branch <jamesbrookesbranch at gmail.com>, "amps at contesting.com"
<amps at contesting.com>
Subject: Re: [Amps] Hallicrafters HT-41

   There is very little difference between the forward drop of mercury rectifiers and solid state ones. On the order of a few volts at best.
A mercury rectifier forward drop would be about 15 volts that is a string of a little more than 20 silicon rectifiers. If the ss rectifiers replaced vacuum rectifiers then there would be an issue.
73
Bill wa4lav

##  why would there be an issue using SS rectifiers to replace a 866 , 816 or even a 5u4g ??   There is no issue, its been done for decades now.  Just use the correct number of diodes
in series, that’s it.   Flip side to all this is.... the oem fil xfmr for the 866 would have to be tossed.   In the oem FWCT, the B+  comes off of the CT of the fil xfmr.   Depending on
how much uf used in the B+  supply, you might want to add step start, etc. 

Jim   VE7RF



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