Hello: as you can see I'm a new user to this forum but not new to car / truck building. Started in 1957.the parts rebuilding ,modifying and changing is old stuff for me. As is bodywork and painting so most of the time I don't have a problem I can't solve somehow without asking sombody . I bet the problem I have has been here before but where do I look? I have a 51 f2 with a perfect radio, 6 volt pos. ground, I am not familar with pos. ground. I am changing to 12 volt neg. ground. Can I make this work safely without burning up my radio and truck ? Or should I just put a 12 volt light in it for show and tell ? The truck will not be original, it will be updated with modern guages but I like the look of the original radio . Will have 289 ,c4 , ford overdrive , or T/10 4/sp. Or 292Y block and T/10 4/sp. I have those and 460 with C/6 , I need to make up my mind soon .After reading a lot of the threads I bet there is somebody out there that can help me even if it bothers me to ask for help .

 

Jim go hunt down Jim Speckman radio . I think he is still in Floridia. You would bewise to replace the tubes with 12 V tubes and be done with the problem incured with the Variance you will have with the 6 V system. Yes you can change the polarity of the ground but since the tubes run almost 45.00 a piece sometimes , why the heck not ? Jim used to advertise heavily in Hemmings Motor News and I used to buy stuff frpm him sporaticly. Hey , got a radio from a 56 ya don't want ? Ed Shaver

 

Thanks; ED that is a lot of help I was not aware that could be done with the ground. I guess thats what I get for working on them old chevys with neg. ground. I may not be to old to learn a little about the old fords after all . How many tubes do they have ? I assume the vibrator or what ever it's called would need to be changed to ? No ,Sorry I don't have a 56 radio but I do have a 55 pasenger car round face 6/v I bought about 20 or 25 years ago and never did use. The only reason I bought it was to save it for somebody to use someday. I am thinking about putting it on ebay soon I am watching to see what they are going for.

 

If you have five pushbuttons on the front then it is the standard radio with 6 tubes. Six pushbuttons up front and it is the deluxe with 8 tubes. To convert to 12v need to change all tubes, vibrator, dial lights and have power transformer rewired. Deluxe radio pulls about 7-8 amps and the standard pulls about 5 amps if want to consider a dropping resistor or regulator. I've fixed quite a few of them but haven't done a 12v conversion yet.

 

I've seen on other forums that they don't care what voltage or polarity is fed to them, check around. Sounds hard to believe, but tubes are very different than transistors.

Edit: this seems to contradict that:
http://classiccarradiodoctor.com/6to12.htm

 

Polarity doesn't matter but voltage does.

 

Thanks everybody, I am listening, auto electrical is the part of car / truck building I'm always a little afraid of. I have installed wire kits but that is different. I saw some add where they used just the front face from older radios, maybe thats for a few different radios only. I thought the add meant they had modern parts inside, but again thanks.

 

Ran a little experiment today. Hooked up the radio to a 6 Volt battery normal polarity, that is positive ground. Turned it on with no problem. Then wired it with a negitive ground, it did'nt like that and blew the fuse.
So this information about how the radio doesn't care about polarity has been debunked.