[ARC5] BC-946

[Ian Wilson]

Well, 5k primary speaker transformers were more readily available than
others, so it wouldn't surprise me if you might get 2x the audio power from
a 6V6 setup than a 12A6 one *using a 5k output transformer and running
on 250v*. This would be a whopping 3dB :)

73, ian K3IMW



On Tue, Apr 29, 2014 at 1:55 PM, D C _Mac_ Macdonald <k2gkk at hotmail.com>wrote:

> BFD - all of ~1.09 dB more output!
>
> * * * * * * * * * * *
> * 73 - Mac, K2GKK/5 *
> * (Since 30 Nov 53) *
> * k2gkk hotmail com *
> * Oklahoma City, OK *
> * USAF & FAA (Ret.) *
> * * * * * * * * * * *
>
>
>
> > Date: Tue, 29 Apr 2014 13:21:04 -0700
> > From: ianmwilson73 at gmail.com
> > To: vk2bcu at operamail.com
> > CC: arc5 at mailman.qth.net
> > Subject: Re: [ARC5] BC-946
>
> >
> > 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
>