[R-390] 6080 in place of 6802

Tue, 8 Jan 2002 17:25:10 -0800 (PST)

Thanks, Barry,

But the 6080's work nice in the Tek scopes so they're
worth the $2 each I paid for mine!

hehehe

Joe

--- "Barry L. Ornitz" <[email protected]> wrote:
> Rodney Bunt <[email protected]> wrote:
> > 6080's can be used in place of 6082's in the R-390
> 
> > (NON A), if you series the filament for both
> tubes....
> > OR you could put a single Diode in series with the
> 
> > filaments if you have no aversion to "sand state"
> devices 
> > in your R-390 (NON A).
> 
> The 6080's filament is rated for 6.3 volts at 2.5
> amps 
> while the 6082 filament is rated at 26.5 volts at
> 0.6 
> amps.  Two 6080 tubes with the filaments connected
> in 
> series would require 12.6 volts to run the filaments
> - not 
> 24 to 28.
> 
> Adding a single diode in series with the filaments
> will not 
> do the trick either.  For the umpteenth time, the
> RMS 
> voltage of half-wave rectified AC is 0.707 times the
> RMS of 
> the original waveform.  The misconception that
> adding a 
> diode in series will allow a 6 volt tube to run on
> 12 volts 
> appeared in several early tomes on the R-390
> receivers and 
> sadly it still persists today.  
> 
> In the case Rodney suggests, the 6080 tubes would
> have over 
> 9.3 volts RMS on the filament of each tube leading
> to very 
> short life.
> 
>            Dr. Barry L. Ornitz     WA4VZQ    
> [email protected]
> 
> 
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