[ARC5] BC-946

Tue Apr 29 16:08:04 EDT 2014

On 30 Apr 2014 at 4:00, Leslie Smith wrote:

>   Hi Mike,
>   You answer prompted me to check the three surplus conversion manuals.
>   I found the article you mentioned in volume #1 - but the mods
>   suggested there are not in the set I have.

That is not unusual: many hams used the Surplus Destruction Manuals' 
articles as guides, adding their own mods to the mods.

>   Basically the BFO is removed and that stage re-wired to be used as an
>   AF pre-amp.
>   In my view, that's un-necessary.

I most emphatically agree.

>  By reducing the cathode resistor
>   (from the 1.5k as wired) the 12A6 will supply good volume.

ARC reduced that resistor to 1K in later models for that very purpose.

>   On the point of details in the article, a 6V6 (or similar) is used in
>   place of the 12A6.
>   Question:  What real advantage would the 6V6 give?

It has a 6.3 VAC filament, while the 12A6 has a 12.6 VAC filament. That is 
the ONLY "advantage" I could ever think of.

>  The 12A6 seems
>   virtually the same.
>   Both are beam tetrodes; the 12A6 is a neat 'toob" - and it's metal!

Well, **I** really like it. It also works very well as an RF amp too.

>   It may be that my questions are pointless.

Not even remotely...

>   A fool can ask more questions in 5 minutes than a wise man can answer
>   in a day.

Ha! Yes. However, I have yet to hear or read a really "stupid" question: here 
or almost anywhere else.

BTW, have you yet decided whether or not to remove your BC-946 parts and 
swap them over to a BC-453 chassis?

You know that there were substantially more BC-453s made than all other 
"ARC-5" receivers put together? Something like 400,000 of them.

Ken W7EKB