[Hallicrafters] Re: [Boatanchors] Replacing rect tubes with diodesquestion

[WA5CAB at cs.com]

I think that a better method (than the resistor and/or the Variac) is as 
follows.  If the original rectifier was a 5R4, 5U4, 5W4, 5Y3 or 5Z3, and if you 
disconnect the 5.2 volt winding from the rectifier socket, is to reconnect that 
winding in series with the primary in the buck direction.  This effectively 
drops the line voltage by about 5 volts (actual drop depends upon actual line 
voltage and relative number of turns in the two windings).  Of course if the 
original rectifier was a 6X5GT or other type using the same filament winding as 
the rest of the tubes, you can't do this.

In a message dated 2/13/2008 10:16:57 AM Central Standard Time, 
km1h at jeremy.mv.com writes: 
> A dropping resistor simply generates more heat and provides no useful 
> function. The tubes are all rated at a higher voltage than is used, 
> recapping takes care of that area and the output transformer has sufficient 
> insulation. The extra B+ current drain is well under 10W.
> 
> Benefit of a resistor in a rebuilt radio =  Zero.
> 
> Benefit of a SS surge protector =  Zero also since they function at the zero 
> 
> crossing of the sine wave.
> 
> Carl
> KM1H
> 
> ----- Original Message ----- 
> From: "Rodger" <wq9e at dtnspeed.net>
> To: "WØQFC" <erastber at tampabay.rr.com>
> Cc: <boatanchors at mailman.qth.net>; "HALLICRAFTERS" 
> <hallicrafters at mailman.qth.net>
> Sent: Wednesday, February 13, 2008 9:36 AM
> Subject: [Hallicrafters] Re: [Boatanchors] Replacing rect tubes with 
> diodesquestion
> 
> 
> >Hi Gene,
> >
> >You also need a dropping resistor to reduce the voltage to close to what 
> >would normally be supplied by the tube rectifier.

Robert Downs - Houston
<http://www.wa5cab.com> (Web Store)
MVPA 9480
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