[Milsurplus] Morale Audio on Ships - oops

[J. Forster]

Oops -

RBO not RDO

My bad. Typo.

-John

=================



Hi Nick,

Thanks very much.

The diagram I have uses a single-ended amplifier with a 117N7 tube, line
operated (no power transformer). It does have the notation RDO on the
print.

What is very useful is to know the characteristics of the audio bus (6 mW
@ 600 Ohms).

I'd presume that each amp has a fairly high bridging input impedance
(>20KOhm maybe ???)so that bus loading would not be an issue? Anybody
know, please?

Best,

-John

=================



> Spoke too soon - here is a photo and info on NT-49545
> http://www.hnsa.org/doc/ecat/cat-1327.htm
>
> and the  NT-49620 (8"speaker)
> http://www.hnsa.org/doc/ecat/cat-1330.htm
> and it's predecessor  NT-49131 (5" speaker)
> http://www.hnsa.org/doc/ecat/cat-1325.htm
>
> Aha! - I thought I had been imaging things as my 49620 is quite a bit
larger than a unit I had seen shipboard.
>
> Nick
>
> On Thu, Jan 13, 2011 at 2:29 PM, Nick England <navy.radio at gmail.com> wrote:
>> Hi John -
>> Look at the NT-49620 selector/amp/speaker here (toward bottom of page).
http://www.navy-radio.com/rcvr-spkr.htm
>>
>> There is also the NT-49545 selector/amp/speaker but I don't have any
photos - just a drawing-
>> http://www.navy-radio.com/navpers/3-58.jpg and this description
Amplifier-Speaker Unit NT-49545
>>    The Navy type 49545 amplifier-speaker unit, seen in figure 3-58, is
a combination audio amplifier and loudspeaker assembly. Its
>> reproduction qualities are considered good. Aboard most ships, it is
installed in berthing and messing compartments as an entertainment
loudspeaker.
>>    All operating controls of the unit are located on the front panel.
They consist of a power on-off switch, a power-on indicating lamp, a
tone control, a volume control, and a channel selector switch that
permits selection of up to five different entertainment (or
>> communication) channels.
>> cheers,
>> Nick
>> www.navy-radio.com
>>
>> On Thu, Jan 13, 2011 at 2:04 PM, J. Forster <jfor at quik.com> wrote:
>>> Hi,
>>>
>>> Does anybody have any info on the distribution of Morale audio to
Officer's compartments on WW II ships.
>>>
>>> Apparently thyere wasw one (or several) line level audio busses and each
>>> space had a selector switch, volume control, small line powered amp (1
tube, 117N7), and speaker.
>>>
>>> Does anybody actually have an amp (or manual for it) that could be duped,
>>> or info on how the audio signal was distributed. Was there a
>>> distribution
>>> amp also?
>>>
>>> Best,
>>>
>>> -John
>>>
>>
>
>