[Kenwood] TS-520/TS-520S Neutralization

Sat, 24 Apr 2004 06:34:29 -0400

Since Kenwood only recommends 200ma anyway(at least if memory serves me
correct), any of them will be fine.

----- Original Message ----- 
From: "Peter A Markavage" <[email protected]>
To: <[email protected]>
Sent: Saturday, April 24, 2004 2:28 AM
Subject: Re: [Kenwood] TS-520/TS-520S Neutralization

> Larry:
> You must have found some pretty healthy 6146/A/B/W's to have plate
> dissipation power of 75 and 90 watts. In my RCA manual for a typical RF
> power amplifier running Class C, the max ICAS plate dissipation rating on
> the 6146/A/W is 20 watts max. and the 6146B rating is 25 watts. Some of
> the earlier Tube manuals initially claimed 35 watts for the "B" but later
> versions toned that number down. You're probably referring to typical
> max. power output for these various tubes not what the plates will
> dissipate per tube.
> Anyway, the difference between 150 and 180 watts won't be noticed on the
> receiving end, so if you run a pair of 6146/A/W's, set the max. plate
> current at around 200 ma. and, if you run a pair of 6146B's, you can run
> them a higher current to squeak a little more power out of them, but
> who's going to notice. Run them at 200 ma also, and they'll last a long
> time.
>
> Pete, WA2CWA
>
> > From: "Larry, K4WLS" <[email protected]>
> > Subject: Re: [Kenwood] TS-520/TS-520S Neutralization
> >
> >
> > 6146W's are NOT a direct replacement for 6146B's. The
> > 6146W's are the miltary version of the 6148B. Nice thing
> > about the 6146W is they are built to Mil Specs and are more
> > rugged than the 6146B. They were originally conceived to
> > run in the old military VHF equipment. Big problem, the plate
> > dissipation power of the 6146W is only 75W compared to
> > 90W for a 6146, 5146A, and 6146B.
> >
> > The 6146B has a plate dissipation power of 90W, so two
> > of them in parallel can be run at 180W input on CW.
> >
> > The 6146W only has a plate dissipation power of 75W, so
> > two of the can be run in parallel for 150W input on CW. If
> > you are running 6146W's better lower the Drive Level on
> > CW or the Mic Gain on SSB. Otherwise you are risking
> > lowering the life of the tubes, failure of a tube, and associated
> > damage to other components in the finals, especially the
> > sreen grid resistors.
> >
> > Plate Dissipation Power (Power Input per Tube) = 1/2 Ip
> > (total plate current - actually cathode current minus screen
> > current) X (plate voltage or key down HV on meter). This is assuming
> > both
> > tubes are perfectly matched and are conducting the same amount of
> > current.
> > Unless you have a matched pair of finals (which you should always
> > run in
> > parallel power amps), most
> > likely one tune is conducting more than the other. All the more
> > reason to stay away from 6146W's.
> >
> > If you have 6146W's in your rig, tune up on CW and advance
> > Drive Level to 225 mA (180W input with key down HV of 800V).
> > Hold key down one or two seconds and watch Ip start
> > dropping. Hold key down longer and listen the the crackling
> > as the plates start getting very hot as the plate dissipation
> > power is being exceeded. If rig covers were off, and final
> > cage removed, hold key down a bit longer and watch the plates
> > start glowing cherry red as the crackling due to heat gets more
> > intense.
> >
> > If your key down HV is more than 800V, do Ip = Key Down HV/
> > 180W to get the Ip to advance the Drive Level to, to try this
> > little
> > test on 6146W's.
> >
> > If you use 6146W, they only good for 150W input - you should
> > always run a matched pair of 6146B's in your Kenwood tube
> > rigs for best performance.
> >
> > Also, you most certainly can use a 6146 or 6146A as a
> > replacement for a 6146B in all TS-520 thru TS-830S as
> > long as the tubes are good.
> >
> > You guys need a good Transmitting Tube Manual such as that
> > put of by RCA or GE, EIMAC - they are still in print.
> >
> > Larry,  K4WLS
> >
> > From: "Ray Friess" <[email protected]>
> > Subject: Re: [Kenwood] TS-520/TS-520S Neutralization
> >
> >
> > Don:
> > I also have a ts 520 .... two of them in fact.  I recently retubed
> > the
> > finals in one of them using
> > 6146W tubes and have had no trouble with neutralization once done.
> > The 6146B is the American version of the finals that come with the
> > Kenwood, and you can use
> > 6146 W in place of 6146B, but NOT for a 6146 or 6146A...
> > Ray wa7itz
> >
> >
> > Donald E. "Buck" Stiles wrote:
> >
> > >Kenwood listees,
> > >
> > >I needed replace the tubes and my TS-520.  I have a 6146W tubes
> > available,
> > >however, I am concerned that I will not be able to neutralize these
> > tubes.
> > >The normal tubes are the 6146/6146A variety.  Has anyone had
> > experience
> > >neutralizing the 6146W in the TS-520/TS-520S?
> > >
> > >Any suggestions appreciated.
> > >
> > >73 de N8CSP k
> > >
> > >
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