[Johnson] Are there " good" modifications ? -yes!

[Peter Markavage]

And the audiophiles also worry about too much oxygen in their speaker
wires and a burn-in period for their AC line cord too.
In our boatanchor communications type gear, stripping electrons from the
cathode is generally the least of our problems.

Pete, wa2cwa

On Thu, 22 Jul 2004 20:42:17 -0700 "David Harmon" <K6XYZ at comcast.net>
writes:
> There is a condition called 'cathode stripping' when B+ is applied
> before the filaments are hot.
> The audiophiles mostly are concerned about this. 
> I'm not sure that this condition will cause a detectable 
> performance
> degradation over a lifetime or two but it does exist.
> 
> Regards
> 
> Dave Harmon
> NSRCA 586
> K6XYZ[at]comcast[dot]net
> Torrance, Ca.
> 
> -----Original Message-----
> From: johnson-bounces at mailman.qth.net
> [mailto:johnson-bounces at mailman.qth.net] On Behalf Of Gary Schafer
> Sent: Thursday, July 22, 2004 7:49 PM
> To: Sherrill E. Watkins
> Cc: Johnson at mailman.qth.net
> Subject: Re: [Johnson] Are there " good" modifications ? -yes!
> 
> There is nothing wrong with applying B+ to a cold tube. It is done 
> all 
> the time in lots of equipment. Look at all the Heath equipment. 
> Hw101, 
> sb101 etc. They all have solid state supplies and the HV comes on 
> the 
> instant the switch is turned on. Cold filaments and all.
> 
> Hallicrafters made the HA6 and HA2, 6 and 2 meter transverters, that 
> 
> operated from the same power supply. All the voltages were fed to 
> both 
> units at the same time. The way one or the other was selected to 
> operate
> 
> was to turn on the filament power on only the one you wanted to use. 
> The
> 
> other one sat there with cold filaments and all the high voltages 
> applied. Worked fine.
> 
> Small tubes do not have a problem with voltages applied before they 
> are 
> warmed up. When you get into larger tubes with over 1000 volts on 
> the 
> plate then you start worrying about that.
> 
> 73
> Gary  K4FMX

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