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

[Peter Markavage]

Having had several B  and C lines, TR-4, TR-4C, and several TR-6's over
the last 25 years, I have never experienced any tube degradation (cathode
stripping or any other anomaly) due to the "instant on" of the HV power
supply. I also presently use several of the National NCX series
transceivers(3, 5, 200, 500) with the same type of "instant on" power
supply and suffer no tube problems. 

As to your other post concerning "electrically matched sweep tubes", I
only "match" my sweep tubes most of the time by manufacturer. I will
agree that some manufacturers, because of probably different
manufacturing processes, developed identical tube types that were
slightly different in their physical and electrical parameters. For me to
find electrically matched sweep tubes is a waste of time because it would
also require that I constantly verify all the circuitry components
surrounding the tubes to  be "electrically matched". No two tubes age at
the same rate so after several hours of operation, your electrically
matched scenario crumbles.

Pete, wa2cwa


On Fri, 23 Jul 2004 09:30:45 -0400 "Sherrill E. Watkins"
<SEWATKINS at dgs.state.va.us> writes:
> Pete: My experience with Drake equipment does not substantate that 
> position.
> I am not talking about audiophiles. - 73- k4own.
> 
> -----Original Message-----
> From: Peter Markavage [mailto:manualman at juno.com] 
> Sent: Friday, July 23, 2004 1:38 AM
> To: > Subject: Re: [Johnson] Are there " good" modifications ? -yes!
> 
> 
> 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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