[Milsurplus] WW II Morale Amp

[mac]

The first tube radio I ever tried to build (late 1940s) was a BC band  
regen that used a single 117N7GT tube, pentode side only, with a 4.5  
volt "C" battery supplying the B+.  Circuit out of Popular Mechanics  
if I remember correctly.  Finally got the thing to work (kind of) with  
the help of my Elmer.  Bought the tube from Allied with paper route  
money.  Used it later in an modulated oscillator circuit that allowed  
me to play phonograph records through the family BC radio (Philco  
cathedral).  Reason I bring this up now is that since that time the  
only "commercial" (or other) use of the 117N7 I've ever run into is  
the one identified in this thread.  Ditto it's brother the 117L7.  The  
tube obviously designed for the thread identified kind of application  
by offering a pentode and a half wave rectifier in one compact octal  
package.  Would guess was used in low end record players too but have  
never run across one.

Dennis D. W7QHO
Glendale, CA

*****************
On Jan 17, 2011, at 3:57 PM, J. Forster wrote:

>> On Mon, Jan 17, 2011 at 3:19 PM, J. Forster <jfor at quik.com> wrote:
>>
>>> Opinions please:
>>>
>>> The more I look at a 1 tube Morale Amp from the MASSACHUSETTS the  
>>> more I
>>> believe it was a modified cheap phonograph. The design is AC/DC  
>>> with a
>>> single 117N7 tube; input and output transformers, and very little  
>>> else.
>>> The purpose was to amplify audio from a 600 Ohm bus to drive a small
>>> speaker in the officers' staterooms. The buses were driven by RBOs  
>>> in
>>> Radio 2.