[Boatanchors] Was a "mix" of 6V & 12 Volt tubes common in National radios?

[Bill Cromwell]

Hi Phil,

Once upon a time manufacturers did whatever was the cheapest way. I have 
a postwar ('45) radio here with a mix of 12 volt and 35 volt heaters 
originally designed for AC/DC radios. However, there is a transformer 
and none of the heaters are in series strings. Apparently it cost a few 
cents less for an extra winding on the iron than use of other tubes. 
Apparently they got a boat load of those tubes *cheap*.

Manufacturers these days would never take any shortcuts like that.

73,

Bill  KU8H

On 10/24/2017 10:43 PM, Phil wrote:
> I've been checking out this NC-140 a bit more, as well as studying the
> manual.  One thing that I noticed is it uses a mix of 12 Volt & 6 Volt
> tube filaments.  Three are 6V, four are 12 Volt, like the 12BE6, 12BA6,
> 12AV6 and so forth.  The transformer has a 12 Volt filament winding with
> a tap at 6V for the 6V tubes and pilot lamps.  Seems like an odd way to
> do things to me. The rectifier is a 5Y3.
>
> Also, the transformer seems a bit "small" for the tube complement and
> runs quite hot, even with the Variac set on 110VAC (looks like the
> filter can was replaced in 2010).
>

-- 
bark less - wag more