[ARC5] BC-946

[Ian Wilson]

Possibly not the reason for the substitution, but the 6V6 has higher
plate dissipation and can provide more audio power (4.5W with a
plate load of 5k) compared to the 12A6 (3.5W / 7.5k) with 250V
supplies.

(When I was looking for alternative tubes to use in a Paraset
lookalike, I hoped the 12A6 was the answer - but you can squeeze
quite a bit more RF power out of a crystal-controlled self-oscillating
6V6 than a 12A6).

73, ian K3IMW



On Tue, Apr 29, 2014 at 11:00 AM, Leslie Smith <vk2bcu at operamail.com> 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.
>
>   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.  By reducing the cathode resistor
>   (from the 1.5k as wired) the 12A6 will supply good volume.
>
>   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?  The 12A6 seems
>   virtually the same.
>   Both are beam tetrodes; the 12A6 is a neat 'toob" - and it's metal!
>
>   It may be that my questions are pointless.
>   A fool can ask more questions in 5 minutes than a wise man can answer
>   in a day.
>
>   73 de Les Smith
>   vk2bcu at operamail.com
>
>
> On Tue, Apr 29, 2014, at 2:46, Mike Everette via ARC5 wrote:
> > I wonder if the "conversion" referred to, might be the infamous "BC-946
> > to Hi-Fi AM Tuner" that was in either Volume 1 or Volume 2 of the Surplus
> > Radio Perversion Manuals.
> >
> > Hmm, years ago I was fortunate to find a NEW BC-946-B in its original
> > cardboard carton, with the dynamotor and a local tuning knob which must
> > have been shipped with it as-new.  And so it has remained, except briefly
> > when it was plugged into a rack to be checked out (worked perfectly); and
> > so it shall remain.  NFS.
> >
> > 73
> >
> > Mike
> > WA4DLF
> >
> > --------------------------------------------
> > On Sun, 4/27/14, Kenneth G. Gordon <kgordon2006 at frontier.com> wrote:
> >
> >  Subject: Re: [ARC5] BC-946
> >  To: "WA5CAB--- via ARC5" <arc5 at mailman.qth.net>
> >  Cc: "Arc5 mail list" <arc5 at mailman.qth.net>
> >  Date: Sunday, April 27, 2014, 7:52 PM
> >
> >  On 27 Apr 2014 at 19:32,
> >  WA5CAB--- via ARC5 wrote:
> >
> >  > Les,
> >  >
> >  > You would probably be time and certainly
> >  final results ahead (if not money)
> >  > to
> >  acquire a decent condition unmodified BC-453-B with
> >  nameplate mounted in
> >  > the same position
> >  and of the same type finish (probably clear matte
> >  > anodize).  Get it working first.  Then
> >  transplant the nameplate and tuned circuits
> >  > out of the BC-946-B into the BC-453-B.
> >  If you are careful with the wires to
> >  >
> >  the BFO transformer, it would look totally original.
> >
> >  Les:
> >
> >  Yes! I would absolutely recommend that you
> >  follow Robert's suggestion.
> >
> >  As he points out, it will be far less expensive
> >  and would show far better
> >  results than
> >  attempting to restore the derelict you have there now.
> >
> >  As has been pointed out, other
> >  than the tuned circuits, the circuitry is
> >  identical between the BC-453 and the BC-946
> >
> >  You would also have to
> >  transplate the dial, but that is only held to the
> >  receiver by one large nut, and is easily
> >  loosened.
> >
> >  Ken W7EKB
> >  ______________________________________________________________
> >  ARC5 mailing list
> >  Home: http://mailman.qth.net/mailman/listinfo/arc5
> >  Help: http://mailman.qth.net/mmfaq.htm
> >  Post: mailto:ARC5 at mailman.qth.net
> >
> >  This list hosted by: http://www.qsl.net
> >  Please help support this email list: http://www.qsl.net/donate.html
> >
> > ______________________________________________________________
> > ARC5 mailing list
> > Home: http://mailman.qth.net/mailman/listinfo/arc5
> > Help: http://mailman.qth.net/mmfaq.htm
> > Post: mailto:ARC5 at mailman.qth.net
> >
> > This list hosted by: http://www.qsl.net
> > Please help support this email list: http://www.qsl.net/donate.html
>
> --
> http://www.fastmail.fm - Email service worth paying for. Try it for free
>
> ______________________________________________________________
> ARC5 mailing list
> Home: http://mailman.qth.net/mailman/listinfo/arc5
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:ARC5 at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>