[ARC5] BIG Variacs and popping breakers.

[Rich Post]

One option for a 68 volt filament line might be a diode and a much smaller
resistor.  The diode will provide the equivalent heating of 84 volts.  The
remaining 16 volts  at 300 mA  is about 5 watts.

(I have also subbed a 6o watt candelabra bulb for a missing ballast adding
a small resistor for the pilot lamp   That really made the radio shine!!
Powered the radio with a variac to determine if the sub would be
appropriate.  Fun stuff!  )

Rich

On Sun, Dec 11, 2016 at 5:47 PM, Scott Robinson <spr at earthlink.net> wrote:

> But Arden, you miss the point: the cap or inductor supplies *only* the
> heater series string, which, for 300 mA tubes, only adds up to 68V.  The B+
> runs off the line directly; I did mention the line cord has three
> conductors..but also failed to mention that none of them were safety
> grounds.
>
> Peace, and no curtain fires,
>
> /scott
>
>
> On 12/11/16 12:43 PM, Arden Allen wrote:
>
>> This method is also useful for restoring the mid-30s AC-DC sets with
>>>
>> resistive 3 wire line cords,the kind that set your curtains on fire. You
>> don't want to use a resistor in the cabinet due to space and heat
>> problems; a capacitor is just right...or certain sizes of fluorescent
>> ballasts, just used as chokes.  ........
>>
>> The problem I have with series impedance voltage reduction is the
>> deterioration of voltage regulation.  For an AA5 current is pretty
>> constant due to the consumption of the 50L6, 50C5, etc. output tube.
>> Likewise for receivers in general.  Anything with substantially varying
>> consumption should be transformer supplied, IMMHO.
>>
>> Arden Allen
>> KB6NAX
>>
>> He who is cruel to animals becomes
>> hard also in his dealings with men.
>> We can judge the heart of a man by
>> his treatment of animals.
>> —Immanuel Kant
>>
>> ______________________________________________________________
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