[ARC5] BC-453 (or R-23) in AM reception

[WA5CAB at cs.com]

Les,

Basically yes.  Except that when you write just "BC-453" with no suffix 
letter you are lumping the low production quantity BC-453-A with the very high 
production quantity BC-453-B.  Which was not what I meant.  The BC-453-A is 
the only one with only Hi-Z output and the BC-453-B is the only one with 
both Lo-Z and Hi-Z output.  The -B was produced in much higher quantities than 
the -A.  Probably more than all the rest combined.  But I miscounted.  
Actually there were seven models.  So the odds are less than 1 in 7 by model and 
probably less than 1 in 15 by production count, given the substantially 
higher production of the BC-453-B.  However, you can get just as much audio out 
of the BC-453-A as out of the others if you use a 4000 ohm to voice coil 
transformer.

The 7 models, with their output impedances, are as follows:

RAV                              500  (very few of these made)
ARA                              500
SCR-274-N BC-453-A     4000
SCR-274-N BC-453-B     4000 & 250
R-23/ARC-5                   500
R-23A/ARC-5                 500
R-148/ARC-5X                500

As far as the amplified speaker goes, certainly it will work so long as you 
get a reasonably close impedance match (say within 2:1).  Regardless of 
which receiver you use, you might want it if operating the receiver on 60V B+ 
in a very noisy environment with a loudspeaker instead of head phones.

In a message dated 01/12/2014 21:20:00 PM Central Standard Time, 
vk2bcu at operamail.com writes: 
> 
>   Hello Robert,
>    When you say "low-Z" audio output "only or as on option", I think 
> you're saying two things.
>    First is that the "low-Z" amounts to 600 ohms (rather than 2000 or 4000 
> ohms).
>    Secondly, because the BC-453 ALONE has hi-Z output I'd be unlucky to 
> not find a "low-Z" set.
>   
>    Do I understand you correctly?
>    Others find the "amplified speaker" works well, so maybe I'm just 
> behind the times!
>    I gotta get "with it!"
>   
>   
>   
>  73 de Les Smith
>  vk2bcu at operamail.com
>   
>   
>  On Mon, Jan 13, 2014, at 10:55, WA5CAB at cs.com wrote:
>  
> >> There were five differently named modes of the LF/MF receiver.  Of 
>> them, all but the BC-453-A have Lo-Z audio output either only or as an option.
>> 
>> In a message dated 01/12/2014 17:32:20 PM Central Standard Time, 
>> vk2bcu at operamail.com writes: 
>> >>> The 500-8 impedance match is close to ideal for matching the 
>>> "command"
>>>   phone output to a speaker.
>>>   This gives modest but useful volume for a loud-speaker (provided I get
>>>   a set with the lower "Z" output impedance).
>>>   This is when I run the set from a 60v B+ supply. 
>>>   I imagine a set running from 150v or 250v would have a good output.
>> 
> 
> 
> 
> 

Robert & Susan Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480