Forums :: Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives :: Books
Support This Site: The Souvenir Shop :: Contributors :: Advertise


It is currently Apr Wed 23, 2014 11:15 am


All times are UTC [ DST ]



Post New Topic Post Reply  [ 2 posts ] 
Author Message
 Post subject: Hallicrafters S-77 question
PostPosted: Nov Sat 03, 2012 7:24 pm 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 833
Location: Germantown, IL USA
Hello,
The schematic shows a 110 ohm, 10 watt resistor across the heater of V-5, a 6H6. All the tubes are in series and have 300 Ma heaters, so I don't understand the need for this resistor. Why is it necessary to lower the heater voltage on the 6H6?

Tom Ackerman


Top
 Profile  
 
 Post subject: Re: Hallicrafters S-77 question
PostPosted: Nov Sat 03, 2012 8:15 pm 
Moderator

Joined: Jan Thu 01, 1970 1:00 am
Posts: 15495
Location: Utica, NY 13502 (USA)
In some cases, it was found that the 6H6 and other detector tubes work better at a slightly reduced filament voltage. A resistor in parallel with the filament when the tube is in a series string filament circuit will accomplish this. If the tube were in a parallel connected filament circuit, there would be a resistor in series with the 6H6 filament. Maybe someone else can explain why the tube works better with a reduced filament voltage.

Dave


Top
 Profile  
 
Post New Topic Post Reply  [ 2 posts ]  Moderators: Marcc, Norm Leal

All times are UTC [ DST ]


Who is online

Users browsing this forum: douglee50, Google [Bot] and 7 guests



Search for:
Jump to:  














Privacy Policy :: Powered by phpBB