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

Sat, 24 Apr 2004 23:04:52 -0600

Larry:
I didnt buy my 100.  I got them directly from the Air Force warehouse 
through Air Force MARS.

Larry, K4WLS wrote:

>Pretty sure the 6146B did not hit the scene until 1973, so do not
>see how 6146W after 1964 can be equivalent to a 6146B.
>
>Don't know where you got your info about the Navy changing specs on the
>6146W beginning in 1963. I was an electronics
>tech in the Navy from 1960 to 1985, I can tell you the specs
>were NEVER changed on the 6146W during that time period.
>Now, got to remember that not only the Navy used that tube
>in old VHF tube gear, the Army and Air Force did as well.
>If the specs had have been changed military supply system
>REQUIRES a change in nomenclature to avoid getting old
>parts mixed up with improved parts. If the specs were changed,
>it would have mostly turned out the tube would have been a
>6146WA
>
>If the 6146W's were the same as, and just as good as, the
>6146B's guarantee you that every commercial company
>that sells ham gear that has a repair facility would have bought
>them all up before you guys bought a 100 or so at the Hamfests
>for about $ 2.00 a tube. Big companies always get the word
>FIRST when the military wants to dump cargo, as the military
>likes to dump it a lot at a time.
>
>Also if you put a new pair in your rig (say your TS-850S) did
>you check the transconductance on one of the old Hickock
>tube testers to see how closely they are matched ??
>
>If you didn't and load up up the rig on CW for 250 mA, one
>tube could be carrying 150 mA (due to higher transconducance)
>while the other is carrying only 100 mA. I have even seen worse
>cases with 6146W's ( one tube carrying 50 mA, while the other
>was straining, crackling, and glowing at 200 mA).
>
>Now for Plate Dissipation. Dissipation is really a poor choice of words for
>this. Thanks to the WA2 who jogged my old brain
>which has not been in too much use lately (technically). Look
>up the word in a dictionary (any), They give as a definition:
>to dispel, disperse, drive away,exhaust, expend, waste, or
>squander.
>
>I had an old EE professor at Clemson who I had in a class
>for RF Power Amplifers. This being back in the mid 1950's,
>electron tube ciurcuits were primarily taught, and we had to
>use slide rules as no electronic calculators. Anyway, everytime
>he referred to the Plate Input Power of a Tube (VP X Ip),
>he referred to it as Plate Dissipation. Well, one day in class,
>I made the mistake of correcting him and telling him that
>plate dissipation was the power that the plate had to expend in
>the form of heat due to the efficiency of the amplifier.  He got
>very hot right quick and told me that plate had to dissipate
>Vp X Ip either in the form of power out, heat from not only the
>plate, but other electrodes as well...........and He finished with
>Mr. Duncan, since the 1st Law of Thermodynamics says that
>energy can neither be created or destroyed, the plate does
>not dissipate, get rid of at any power at all, it merely coverts
>the electrical power to heat energy.
>
>So...he made some good points there even though the definition
>of Plate Dissipation is the plate input power to the tube that doesn't make
>it as outout power so therefore is converted to
>heat energy by the plate. Other losses in an RF Tube Amp as well, such a
>power dissipated [electrical power converted to heat energy :-)  :-)] by
>cathode and screen resistors, I squared R
>losses in tank circuit, etc.
>
>Now, I just pulled a muscle and got a few good sneezes from
>pulling my old 1972  RCA Transmitting Tube Manual from my dusty book shelf.
>It says:
>
>Plate Dissipation for 6146 and 6146A is 25W. 6146B not listed.
>Hmmmmm.....bet it not around yet as I suspected.
>PlateDissipation for 6146W is 25 W.
>
>Pulled down my 1976 RCA Transmitting Tube Maual. It says
>Sneeze, sneeze Oooops !!  SRI:
>6146/6146A Plate Dissipation is 25 W
>6146B Plate Dissipation is 33 W
>6146W Plate Dissipation is 25W  (don't look like upgrade yet).
>
>By the way the 6146B's in parallel in the TS-520 thru 830S
>(which is only Kenwood Rigs I intimate with) the final amp
>runs Class AB1 (the 1 means that the driver does not draw
>any grid current. They run Class AB1 in both CW and SSB.
>Class AB necessary for linear operation of power amp in SSB
>mode.
>
>About the max efficiency you going to get with Class AB
>in parallel is 60 %. So for 180W DC input, you can expect
>to get no more than about 108W output. If the two tubes
>were in push-pull, the maximum theoretical efficiency would
>be 79.8 %. Push-pull tube amps for RF can be a pain.
>
>The old Drake TR-4C:  3 - 6BJ7's (???) in parallel, and it
>operated Class AB2. On voice peaks when operating SSB,
>the Driver would draw some grid current from the finals and
>that is how the ALC was derived. The TR-4C ran Class AB1
>in CW however.
>
>Now you may run 6146W's the rest of your life in your
>Kenwoods and never have a problem, but if I ever get any
>more Kenwood tube gear - it would have to be a matched
>pair of 6146B's in finals for me. Finding a brand new set of RCA
>matched pair 6146B's, would be like Earl Scruggs finding
>a pre WWII Gibson banjo in somebodys attic !!
>
>73,  Larry
>
>
>
>When I was usiung 6146B's in the Kenweood tube gear, I
>always had oretty good luck getting Matched Pairs from
>RF Parts out in CA. Pretty sure they made in Mexico. I
>always looked them over to check for element sagging,
>loose plate caps etc, then checked them for transconductance
>on a Hickock to see if they really matched. I then put them in my
>bench TS-520S with final covers off, and with light off checked]
>for any arcing in tubes or bluish or yellow glow with key down at
>20 Ma.  If all that OK, I made sure I could neuteralize them and get 80W
>output 0n CW on 10M with the test rig. All this using a
>50 Ohm 1 KW Dummy Load.
>
>----------------------------------------------------------------------------
>------------
>
>I think this from Glen Zook is pretty definitive....
>
>Any 6146W tube made after 1964 should be the
>equivalent of the 6146B.  The military changed the
>requirements but did not change the nomenclature.  As
>such, the very old 6146W are the equivalent of the
>6146A but, depending on the individual contract with
>the tube manufacturer, the 6146W tubes started being
>basically an equivalent of the 6146B in mid-1963 and
>all contracts were converted by the end of 1964).
>
>The 2001A is the Japanese equivalent of the 6146B.
>
>Collins had to redesign the neutralization circuitry
>of the 32S-3 series and KWM-2 series to allow the
>military to use the "new" 6146W tubes.  When a 6146B
>or "new" 6146W is installed in the S-Line equipment
>usually the neutralization circuitry "burns up" within
>a very short period of time.  On those units with the
>"improved" neutralization circuitry any of the 6146
>series tubes can be utilized.
>
>Actually, the TS-520 will work with the 6146 / 6146A /
>8298 tube.  But, the power should be reduced to no
>more than 75% of what it will run with the 6146B /
>8298A (and the "new" 6146W) tubes.  He is correct in
>saying that the 2001A is replaced by the 6146B.  If he
>wants to only install 6146B tubes in the units that he
>services, then that is definitely his option.  But, a
>direct substitute for the 6146B is any 6146W with a
>code date after 1964.  In fact, most 6146W tubes with
>a code date of 1964 are going to be the 6146B
>equivalent.  However, there were a very few
>manufacturers that were completing original contracts
>and were still manufacturing 6146A equivalents.
>
>Also, there was a certain manufacturer (I have
>forgotten which one, but it was not a "major" tube
>manufacturer) that produced many thousands of 6146W
>tubes that were not good for anything but audio!  The
>company got paid for the tubes, and then went bankrupt
>before any of them got into service.  When they were
>tried in Collins S-Lines most of the tubes wouldn't
>put out but a few watts on 80 meters and by the time
>they were tried on 10 meters they didn't work at all!
>
>Those tubes sometimes show up in the amateur market.
>Of course they are brand new.  However, unless you are
>going to use them in a modulator (like in the Johnson
>Valiant) they are useless!  Unfortunately, the bulk of
>these tubes go on eBay.  I don't have any manufacturer
>information or even code dates except that I believe
>these were made in the mid-1970s.
>
>Glen, K9STH
>
>--- Ray Friess <[email protected]> wrote:
>
>The Kenwood group has been discussing putting 6146W
>tubes in the ts 520, which I have done with no
>problems.  Your discussion on when you can use a W in
>place of a B has been brought up, but this guy
>apparently doesnt believe you..... I think youre
>right, he's wrong.
>
>The TS520's were designed for the S2001A tube. The
>direct replacement for the S2001A is the 6146B. Nuff said.
>
>=====
>Glen, K9STH
>
>Web sites
>
>http://home.comcast.net/~k9sth
>http://home.comcast.net/~zcomco
>
>
>
>
>Clif Holland wrote:
>
>  
>
>>The TS520's were designed for the S2001A tube. The direct replacement for
>>the S2001A is the 6146B. Nuff said.
>>
>>Clif Holland, KA5IPF
>>AVVid
>>Authorized Kenwood and Icom Service Center
>>816 W Shady Grove Rd
>>Irving, TX 75060
>>
>>www.avvid.com
>>
>>1-800-214-5779
>>972-870-0630 (local)
>>
>>
>>----- Original Message ----- 
>>From: "Ray Friess" <[email protected]>
>>To: "Larry, K4WLS" <[email protected]>
>>Cc: "Donald E. "Buck" Stiles" <[email protected]>; <[email protected]>
>>Sent: Saturday, April 24, 2004 9:31 AM
>>Subject: Re: [Kenwood] TS-520/TS-520S Neutralization
>>
>>
>>
>>
>>    
>>
>>>I got my information and 6146 tutorial from Glen Zook K9STH, who is an
>>>acknowledged expert
>>>on 6146 tubes and their successors.  He has answered the question about
>>>using 6146W tubes
>>>many times....   I have used them in one of my ts 520 rigs for a couple
>>>years now without any
>>>problems at all.  When the original tubes in my second ts 520 go, I will
>>>replace them with W's
>>>as well.   I have 100 of the tubes........   all brand new.
>>>Here's his web site and here's a portion of what he said just recently...
>>>
>>>http://home.comcast.net/~k9sth
>>>http://home.comcast.net/~zcomco
>>>
>>>Unless you want some pretty "hairy" experience with
>>>neutralization (and they may or may not neutralize) do
>>>
>>>not use 6146B tubes or any 6146W tubes with a "code
>>>date" later than 1964 (which are basically the same
>>>tube as the 6146B).  Sometimes the 6146B works in
>>>equipment that was originally designed for the
>>>6146/6146A/8298 series, but using the 6146B/8298A
>>>often results in all sorts of problems.
>>>
>>>
>>>
>>>Larry, K4WLS wrote:
>>>
>>>
>>>
>>>      
>>>
>>>>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
>>>>>
>>>>>
>>>>>- - -
>>>>>
>>>>>Your moderator for this list is:
>>>>>Larry Wilson KE1HZ [email protected]
>>>>>
>>>>>_______________________________________________
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>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>          
>>>>>
>>>>- - -
>>>>
>>>>Your moderator for this list is:
>>>>Larry Wilson KE1HZ [email protected]
>>>>
>>>>_______________________________________________
>>>>Kenwood mailing list
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>>>>http://mailman.qth.net/mailman/listinfo/kenwood
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>        
>>>>
>>>- - -
>>>
>>>Your moderator for this list is:
>>>Larry Wilson KE1HZ [email protected]
>>>
>>>_______________________________________________
>>>Kenwood mailing list
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>>>http://mailman.qth.net/mailman/listinfo/kenwood
>>>
>>>
>>>
>>>      
>>>
>>
>>
>>
>>
>>    
>>
>
>- - -
>
>Your moderator for this list is:
>Larry Wilson KE1HZ [email protected]
>
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