[ARC5] Low B+ supplies for BC-454-B RX?

[Dennis Monticelli]

I'd like to add just one thing.  I've found that the BFO often does
not start up on 24V.  I like to use the BFO, so I run mine on about
70V where all of mine startup readily.  You definitely have to pay
more attention to the capacitors at 70V, but not nearly as much as
250V.  There is the added benefit of more audio.  If you prefer to
keep as many original caps as you can, then try 24V first and see if
you are satisfied with the performance.

Another thing to point out is that the low voltage operation makes it
easier to go portable.  I've taken mine to Field Day and run purely
off batteries.

Dennis

On 4/9/06, David Stinson <arc5 at ix.netcom.com> wrote:
>
> ----- Original Message -----
> From: "Roger Basford" <roger at new-gate.co.uk>
> Subject: [ARC5] Low B+ supplies for BC-454-B RX?
>
>
> > Hi All,
> >
> > I believe that it's quite feasible to run a BC-454, etc from a 50 volts B+
> > supply, is this correct?
>
> Your BC-454 will run spendidly on +50 VDC.
> I run mine on 24 VDC.
> You will have somewhat less audio out.
> I use an external amplified speaker
> (cheap as dirt from any computer surplus outlet).
> In larger receivers, I tack-in a cheap little audio amp
> or LM-386 and run it off the filament power.
> You will find you have less need to replace leaky caps,
> since leakage currents often drop to microamps or less at low voltage
> and the cap still works fine without the stress of +250 volts.
> I have several that work just fine without changing a single
> componant.  I clean switches/contacts, power it up and align
> it and away she goes.  Dead short caps and flat open resistors
> still need changing, but at low B+ that amounts to a small fraction
> of the work that needs doing if you're going to run +250.
> And another big plus for me, since I tend to get
> "scatter-brained" and get "bit" by high-voltage:
> +24 volts don't hurt much.  +250 volts will kill you.
>
> The radio runs cooler and stablizes faster.
> Sensitivity is not much affected- at least, not in any meaningful way.
> Low B+ in boatanchor receivers is, IMHO, the most desireable
> way to run them, providing the enjoyment of using them while
> preserving the maximum amount of original workmanship.
>
> 73 Dave S.
>
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