[ARC5] 24V B+ supply for "command" receivers.

[john rose]

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> From: brokenthumb at live.com
> To: wa5cab at cs.com
> Subject: RE: [ARC5] 24V B+ supply for "command" receivers.
> Date: Sun, 10 Mar 2013 01:17:05 -0700
>
> Did the R808 also run the tubes at 24v B+ without using the control grid as an attractor/accelerator?
> The R389, R390, R390A, R391 and my 392 all use tube filaments in series/parallel. 12AU7 grounded grid triodes as diodes in the 392.
> If the filament voltage is the only thing special, what 6/12 will replace it without hacking up the rest of the circuit? At one time, a long time ago, when 392 IF strips were cheap. I thought about setting up several HF Command RX and converting their IF strip outputs to 455kc and then through the 392 module so these are not idle questions. I would have preferred to use 6/12 filaments in parallel with high B+ 'just because'. Didn't really want a separate 24v power supply and have you priced these 26v tubes lately? The national debt.
> ----------------------------------------
> > From: WA5CAB at cs.com
> > Date: Sun, 10 Mar 2013 01:17:29 -0500
> > To: arc5 at mailman.qth.net
> > Subject: Re: [ARC5] 24V B+ supply for "command" receivers.
> >
> > The only thing special about the tubes in the R-392/URR is their filament
> > voltage rating. R-808/GRC-14, the competitor to the R-392, uses common 6V
> > and 12V filament tubes like the 6BE6 and 12AT7 in the common up until that
> > time series/parallel hookup.
> >
> > In a message dated 03/09/2013 23:25:00 PM Central Standard Time,
> > brokenthumb at live.com writes:
> >> I have read the responses to my questions with interest. None of them
> >> have addressed my questions. I shall restate them.
> >>
> >> The R392 uses a series of tubes designed to run at 24v on the filaments
> >> and B+. However the tube spec sheets I have read all go out to at least 200v.
> >> Question; will a tube designed for 24v B+ SAFELY run with B+ at 200v or
> >> more? Question; if it does, then is this series of tubes really 6/12v tubes
> >> "in drag" so to speak? Comment; obviously these tubes run on 24v B+ and run
> >> very, very well. In my (not even close to humble) opinion, the R392 as an
> >> SWL rig is very nearly the equal of the R390. Collins designed both and if
> >> you lift the lids on both, they very nearly look the same except for size.
> >> Oh, BTW if you compare the selectivity graphs of the 85kc IF of the '453/R23
> >> with that of the 392 at 2kc, they are virtually identical. 6 gain stages
> >> at 455kc will do that.
> >>
> >
> > Robert Downs - Houston
> > wa5cab dot com (Web Store)
> > MVPA 9480
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