Author Topic: 6V to 12V Conversion; Radio ?  (Read 185 times)

Offline jackworstell

  • Posts: 151
    • CLC Member
      CLC Member #7558
  • Name: J L Worstell CLC #7558
6V to 12V Conversion; Radio ?
« on: October 03, 2017, 07:24:45 PM »
We are thinking about converting our 1937 Cadillac series 60  from 6V to 12V.   The car still has the original 5X Wells Gardner radio and it works.

If we convert the car to 12V.......would inserting a resistor ( of appropriate ohms and wattage )   in series in the power wire to the radio take care of this aspect of the conversion ?    Or is it more complicated than this ?

Jack Worstell    #7558     jlwmaster@aol.com

Offline 1937 LaSalle coupe

  • 1937 LaSalle coupe CLC # 26365
  • Registered User
  • Posts: 214
    • CLC Member
      CLC Member #26365
Re: 6V to 12V Conversion; Radio ?
« Reply #1 on: October 03, 2017, 07:39:32 PM »
Hello Jack. You are going from 6 volts positive ground to 12 volts negative ground. I would contact a professional radio rebuilder. Good luck... John C. Lehman ...

Offline jackworstell

  • Posts: 151
    • CLC Member
      CLC Member #7558
  • Name: J L Worstell CLC #7558
Re: 6V to 12V Conversion; Radio ?
« Reply #2 on: October 03, 2017, 07:41:23 PM »
John...we would use a 12V positive ground alternator.....they are available.

Jack

Offline klinebau

  • Posts: 13
  • Name: Kurt Linebaugh
Re: 6V to 12V Conversion; Radio ?
« Reply #3 on: October 03, 2017, 09:00:55 PM »
I would not use a series resister.  Check out this article.  http://www.studebaker-info.org/Tech/6-12V/6-12-6.html
1970 Cadillac Deville Convertible
Detroit, MI

Offline TJ Hopland

  • Posts: 6712
Re: 6V to 12V Conversion; Radio ?
« Reply #4 on: October 03, 2017, 10:54:27 PM »
A resistor only sort of works for something that has a consistent load/draw.   Something like a radio likely varies somewhat depending on what is playing and how loud.   Other downside to a resistor is you are turning half the power into heat so its a waste especially for larger loads. 
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
75 Eldo rusty but trusty
80 Eldo Diesel
And other assorted stuff I keep buying for some reason

Offline jackworstell

  • Posts: 151
    • CLC Member
      CLC Member #7558
  • Name: J L Worstell CLC #7558
Re: 6V to 12V Conversion; Radio ?
« Reply #5 on: October 04, 2017, 07:34:55 AM »
Thanks

Offline bcroe

  • Posts: 2016
    • CLC Member
      CLC Member #14630
6V to 12V Conversion; Radio ?
« Reply #6 on: October 04, 2017, 08:16:42 AM »
Don't even think about trying to use a resistor.  Generally tube radios
don't care about polarity, unless it uses a 6 pin vibrator or a dynamotor. 
The simplest method could be a 12V to 6V switching (cool, efficient
operation) supply, needs to be filtered against radio interference. 

I would NOT recommend a positive ground alternator.  Your radio
likely doesn't need it, hardly anything else cares, but any modern solid
state stuff you might want to use will want negative ground.  Bruce Roe

Offline jackworstell

  • Posts: 151
    • CLC Member
      CLC Member #7558
  • Name: J L Worstell CLC #7558
Re: 6V to 12V Conversion; Radio ?
« Reply #7 on: October 04, 2017, 08:38:24 AM »
klinebau...thanks for the link....very interesting.   I found the explanation of how to make a 12V to 6V regulator complete and easy to understand

bcroe....would you happen to have a link describing a switching supply ?     No need to go into a detailed explanation here on the forum...just looking for a hint on where to go to so as to get a better understanding.

Jack




Offline bcroe

  • Posts: 2016
    • CLC Member
      CLC Member #14630
6V to 12V Conversion; Radio ?
« Reply #8 on: October 04, 2017, 12:39:19 PM »
Best to buy a switcher of the needed capacity; they are somewhat complex
but cheap on Evil Bay and other places.  Some input and output filtering
will probably be needed if it isn't designed for the specific app. 

The 7805 class reg is a LINEAR reg that will burn up the extra voltage,
dissipating as much power as the radio.  These are generally not the way
to go for this many amps. 

Bruce Roe

Offline jackworstell

  • Posts: 151
    • CLC Member
      CLC Member #7558
  • Name: J L Worstell CLC #7558
Re: 6V to 12V Conversion; Radio ?
« Reply #9 on: October 04, 2017, 02:03:16 PM »
Bruce   the factory radio in our 1937 Cadillac is a Wells Gardner 5X.  It has a six pin vibrator  ( equivalent to a Mallory 248 I think )
The vibrator has markings on it to the effect that one position is for negative ground systems and by physically  rotating it 180 degrees
it will work for positive ground systems.   From my somewhat limited understanding of vibrators..... this is a synchronous unit......it provides rectification as well as the source of an oscillating waveform.

So......based on your previous remarks,
            the Wells Gardner 5X radio would be polarity sensitive ??

 and....since the vibrator can be flipped 180 degrees.....it this particular instance this radio can be used with either positive ground systems or with negative ground systems ?

Thanks   for the advice....Jack

Offline bcroe

  • Posts: 2016
    • CLC Member
      CLC Member #14630
Re: 6V to 12V Conversion; Radio ?
« Reply #10 on: October 04, 2017, 03:44:45 PM »
Bruce   the factory radio in our 1937 Cadillac is a Wells Gardner 5X.  It has a six pin vibrator  ( equivalent to a Mallory 248 I think )
The vibrator has markings on it to the effect that one position is for negative ground systems and by physically  rotating it 180 degrees
it will work for positive ground systems.   From my somewhat limited understanding of vibrators..... this is a synchronous unit......it provides rectification as well as the source of an oscillating waveform.

So......based on your previous remarks,
            the Wells Gardner 5X radio would be polarity sensitive ??

 and....since the vibrator can be flipped 180 degrees.....it this particular instance this radio can be used with either positive ground systems or with negative ground systems ?
Thanks   for the advice....Jack 

Jack, I didn't know about the 180 degree option, but yes that is going to
be the only polarity sensitive part of the radio.  With a DC-DC converter,
the radio can stay stock (but flipped). 

There is another way around this, disconnect the transformer secondary
wires from the vibrator pins and wire in a couple diodes; then the radio
isn't polarity sensitive.  This method could also be used to convert to a 4
prong vibrator if you can't find a good 6, could be wired as an external plug
in to the 6 pin socket.  good luck, Bruce Roe