from the'63 RCA Tub Man....2A3 power triode,plate 200v,3.5W mue 60, 2A5,twin diode/high mue triode,, 2A7 Pentagrid converter---- more stuff, diodes, etc... then there are the 3V stuff..... the Manuel is gud reading on long winter nights...... klc ----- Original Message ----- From: Edward B Richards <[EMAIL PROTECTED]> Date: Friday, December 30, 2005 12:09 pm Subject: Re: [AMRadio] WTB/WTS and a question
> Hi Brian; > > In my ignorance, I have never heard of 2 volt tubes. What are their > numbers? Thanks and HNY. > > 73, Ed Richards K6UUZ > Simi Valley, Ca 93065 > Home of the Air Force 1 pavilion > > On Fri, 30 Dec 2005 10:21:15 -0600 Brian K Harris > <[EMAIL PROTECTED]> writes: > > Good Morning, > > > > 1. I would like to buy or swap for two solid state plug-in > > replacements > > for the 872A mercury vapor rectifiers for my KW-1. Enuf said. > > > > 2. I am restoring a broadcast/shortwave radio set for my > brother. > > It is > > an RCA 8BT, battery operated 'farm set' from the 30's. In > addition > > to > > using three 45V batteries in series for the 135V B+, it used > four > > small > > 1.5V cells for biasing the 1st detector and the 1st and 2nd > IF's, > > and a > > multi-tapped battery to get 3V bias for the 2nd detector and > 7.5V > > bias for > > the audio driver. As my brother doesn't live on an electricity > > deprived > > farm, I am building a solid state AC supply to meet those needs. > > > > The tubes all have 2V filaments. The radio has two inputs for a > > filament > > supply, 2V or 2.5V (the 2.5V input merely inserts a series > > resistor). My > > question is....why did anyone manufacture 2V filament tubes and > what > > kind > > of battery put out 2V or 2.5V? I am building a solid state > supply > > for the > > 2V requirement as well so the question is merely to satisfy my > > curiosity. > > > > By the way, this set uses a pair of push-pull 49's for the audio > > output > > stage. These are zero bias tubes in Class B with 3.5W > capability. > > Very > > cool. > > > > Thanks for reading, > > > > Brian WA5UEK > > > > ______________________________________________________________ > > AMRadio mailing list > > Home: http://mailman.qth.net/mailman/listinfo/amradio > > Help: http://mailman.qth.net/mmfaq.html > > Post: mailto:AMRadio@mailman.qth.net > > AMfone Website: http://www.amfone.net > > AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb > > > > > ______________________________________________________________ > AMRadio mailing list > Home: http://mailman.qth.net/mailman/listinfo/amradio > Help: http://mailman.qth.net/mmfaq.html > Post: mailto:AMRadio@mailman.qth.net > AMfone Website: http://www.amfone.net > AM List Admin: Brian Sherrod/w5ami, Paul Courson/wa3vjb >
