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eHam Forums => Boat Anchors => Topic started by: KB2WVO on September 10, 2017, 11:07:33 AM



Title: 6146??? 6146B - w
Post by: KB2WVO on September 10, 2017, 11:07:33 AM
wondering can 6146B's / 6146W's run in place of 6146/6146A's ???   manual doesnt say a thing on if yes or no..
HK SB110.


Title: RE: 6146??? 6146B - w
Post by: WA5VGO on September 10, 2017, 12:06:24 PM
They'll work fine.


Title: RE: 6146??? 6146B - w
Post by: KB2WVO on September 10, 2017, 12:49:10 PM
They'll work fine.

awsome ty ...
i did try them.. seems radio is outputin only around 50 watts... i know the tubes are good as i took them out of my 101ZD.. they tuned to 100 there..

it might be just that only 50 watts on 6. the manul doesnt give much info .. at least the one i found so far.. grrrr lol ..


Title: RE: 6146??? 6146B - w
Post by: W1BR on September 10, 2017, 01:52:17 PM
What is the grid current in tune-up?  Can you drive to at least a few mA of grid on those tubes?  This could be a driver, alignment, or other issue.

Pete


Title: RE: 6146??? 6146B - w
Post by: WA5VGO on September 10, 2017, 05:13:36 PM
What is the grid current in tune-up?  Can you drive to at least a few mA of grid on those tubes?  This could be a driver, alignment, or other issue.

Pete

Agree. See if you can draw grid current. If you can't, you don't enough drive.


Title: RE: 6146??? 6146B - w
Post by: KB2WVO on September 10, 2017, 05:18:23 PM
radio meter shows 250ma. she seems to tune up... and the MAs do adjust. the output is in a xtern watt/swr. SX200 thats trustworthy. i checked it with other meters n radios n such ..
the W's were in a 101zd givin to me from a ham who had gotten it with the cough 11m job done to it. grrrrr.....
so they might be tired... tho they did do 100 on 80m in the 101zd..



Title: RE: 6146??? 6146B - w
Post by: WW7KE on September 10, 2017, 06:34:25 PM
Back in my Novice days (1970-71), I swapped the 6146 in my Heathkit DX-60B for a 6146B.  Worked perfectly, and supposedly could even be tuned up to run 120 watts input instead of the "regulation" 90.  Never tried it, though.


Title: RE: 6146??? 6146B - w
Post by: W1BR on September 10, 2017, 07:16:23 PM
radio meter shows 250ma. she seems to tune up... and the MAs do adjust. the output is in a xtern watt/swr. SX200 thats trustworthy. i checked it with other meters n radios n such ..
the W's were in a 101zd givin to me from a ham who had gotten it with the cough 11m job done to it. grrrrr.....
so they might be tired... tho they did do 100 on 80m in the 101zd..



What about GRID current??

Pete


Title: RE: 6146??? 6146B - w
Post by: KB2WVO on September 10, 2017, 10:19:19 PM
radio meter shows 250ma. she seems to tune up... and the MAs do adjust. the output is in a xtern watt/swr. SX200 thats trustworthy. i checked it with other meters n radios n such ..
the W's were in a 101zd givin to me from a ham who had gotten it with the cough 11m job done to it. grrrrr.....
so they might be tired... tho they did do 100 on 80m in the 101zd..



What about GRID current??

Pete
the radio meter  shows grid ??? iam still learning some of this.. tuning up radio . sset final knob to show max meter reading. it does do that. ...
if i need to check from in the radio.. how to  ???
so grid no idea to be truthful.

goin to make video and post to youtube... link soon..


Title: RE: 6146??? 6146B - w
Post by: KB2WVO on September 10, 2017, 10:54:23 PM
heres a video.. if anything you like to see to help give a idea.. let me know. ill try and do a video for it..
these same valves.. 6146W's in a 101ZD show about 50 watts on 10m and 100 watts on 75m... no idea if it helps....the 6146A's that been in radio for over 20 plus years are only giving about 35 watts on 6m...
 
https://youtu.be/ARlLnCEvrQY (https://youtu.be/ARlLnCEvrQY)


Title: RE: 6146??? 6146B - w
Post by: G3RZP on September 11, 2017, 02:01:40 AM
6146W is a mechanically ruggedized 6146A for use in equipment subject to shock and vibration. It has a 25 watt plate dissipation rating - some people say 35 watts like the 6146B, but I haven't found a data sheet that says that. Or been given a lead to one that says that...

6146B is 35 watt plate dissipation tube. Claimed to be directly interchangeable with 6146 or 6146A, but in some Motorola and Collins transmitters, it wasn't.


Title: RE: 6146??? 6146B - w
Post by: W1BR on September 11, 2017, 06:06:44 AM
Had to dig out the manual... looks like they skipped the grid current function, and just go by being able to drive the plates to 250 mA.  Usually you'd want to see around 2 mA drive on those grids, but the SB-110 has no provision for metering grid current in tune up.

Pete


Title: RE: 6146??? 6146B - w
Post by: KB2WVO on September 11, 2017, 11:06:18 AM
is it possiable ?? valves go bad on some bands?  as they do 100w on 75m but 50w on 10m and and 6m ??
iam still learnin on this stuff. soo i have no idea..


Title: RE: 6146??? 6146B - w
Post by: W1BR on September 11, 2017, 11:17:57 AM
If they made 100 watts output on ten meters, then they are probably good tubes.

There are too many variables to answer your question.   Grid drive, plate and screen voltages, state of the SB-110 radio's alignment, or other issues. And, unless you can verify the wattmeter's accuracy,  or whether the RF impedance of the antenna is even close to 50 ohms--which directly affects the wattmeter's accuracy, this will be a hard question to answer without guessing. 

Pete


Title: RE: 6146??? 6146B - w
Post by: KB2WVO on September 11, 2017, 12:29:37 PM
If they made 100 watts output on ten meters, then they are probably good tubes.

There are too many variables to answer your question.   Grid drive, plate and screen voltages, state of the SB-110 radio's alignment, or other issues. And, unless you can verify the wattmeter's accuracy,  or whether the RF impedance of the antenna is even close to 50 ohms--which directly affects the wattmeter's accuracy, this will be a hard question to answer without guessing.  

Pete

the antenna is 50 ohms. the watt meter has been checked with other meters also the ones radios . they all matched. the tubes did 100 watts in a 101zd on 75m. not 10m. 10 meters was 50 watts.
i took the valves out of it to see what the sb110 would do and see if the 6146As that were in it were good. so the 6146Ws do a lil better but they could be bad also ...
as said the 6146Ws from the 101ZD did 100 watts on 75m same radio 10m did 50ish watts..
in the sb110 the 6146Ws do 50ish watts.

dummy load , 2 diff antennas.. all the same 50 watts.

PS:/// on the SB110 has a switch marked... 50.0 - 50.5 - 51.0 -51.5
so i set it to 51.5 on the switch ... then the dial in middle is at 40....  puts it at 51.540  it puts out 100 watts...

no idea what this meens.. but hope someone knows ..
SWR is 2 at 51.540 and 1.3 at 50.125



Title: RE: 6146??? 6146B - w
Post by: KD0REQ on September 11, 2017, 12:43:35 PM
did you neutralize the tubes in the new rig? yah, yah, yah, negligible differences Cpg Cps etc. they put neutralization instructions in the manual for a reason.


Title: RE: 6146??? 6146B - w
Post by: KB2WVO on September 11, 2017, 01:50:59 PM
did you neutralize the tubes in the new rig? yah, yah, yah, negligible differences Cpg Cps etc. they put neutralization instructions in the manual for a reason.
iam lookin thru the build manual i see nothing .. on the rite way to do it for this rig.. iam sure its a basic idea. but i would like to be 1000% sure on how its done ..


Title: RE: 6146??? 6146B - w
Post by: KD0REQ on September 11, 2017, 02:08:57 PM
To expand... power tube specs are rated in a band of ranges. They indicate manufacturing tolerances, and the chances of two random tubes matching what you had installed are not great. This means different gains and thus different reactions to stuff around them. So on changes of power tetrodes, you have a different system at RF. So you need to neutralize and likely change the drive level. The equipment intolerant of 6146B tubes do not have a wide enough neutralization range (or none at all, if the designers intended you buy their own selected tubes.)


Title: RE: 6146??? 6146B - w
Post by: KD0REQ on September 11, 2017, 02:13:31 PM
Neutralization is generally capacitive, a trimmer or bendable wire or plate. Generally, you take the B+ off the plates, set a CW signal on at the top frequency, and adjust the measured output down to some value with the neutralization cap. If your manual does not have the directions, ask around.


Title: RE: 6146??? 6146B - w
Post by: KB2WVO on September 11, 2017, 04:30:32 PM
Neutralization is generally capacitive, a trimmer or bendable wire or plate. Generally, you take the B+ off the plates, set a CW signal on at the top frequency, and adjust the measured output down to some value with the neutralization cap. If your manual does not have the directions, ask around.

ill have to check around for a heathkit group of some sorts.. this old girl is in great shape.. untouched for 22 years. as i owned it 22 years ago.. sold it and got it back sunday .. and the old valves that were in it them were still in it..

so a good goin over might be in store. and the ham i sold it to. knew tons more then i ever will.. tho he is SK now. sadly missed to ..

lil by lil ill figure it out i guess. lots to learn for sure. the fun of the hobby .. never stop learning something new every day .


Title: RE: 6146??? 6146B - w
Post by: KD0REQ on September 11, 2017, 06:24:57 PM
on the classic Heathkits, the instructions are the same for the HW-100, 101, SB-100,101, 102.  it's in all those manuals, floating around behind the build instructions.  you lift two wires on a terminal strip, and follow the instructions.  danger, warning, fattening, that's up to 800 volts, spark it off to ground and unplug the power supply from the wall, just in case, before lifting the B+ and before replacing it. the circuitry is almost identical one to the other, especially in the final cage.


Title: RE: 6146??? 6146B - w
Post by: KB2WVO on September 11, 2017, 07:50:09 PM
i read thru the manual. found the area.. its under transmitter alignment..
about 20 or so steps.. and iam about 99% sure it hasnt been done in at least 22 years..
so iam reading it a few 100 times to absorb it. and understand it a lil..

lordy i love radios.. so much fun..


Title: RE: 6146??? 6146B - w
Post by: KB2WVO on September 11, 2017, 10:01:37 PM
on the classic Heathkits, the instructions are the same for the HW-100, 101, SB-100,101, 102.  it's in all those manuals, floating around behind the build instructions.  you lift two wires on a terminal strip, and follow the instructions.  danger, warning, fattening, that's up to 800 volts, spark it off to ground and unplug the power supply from the wall, just in case, before lifting the B+ and before replacing it. the circuitry is almost identical one to the other, especially in the final cage.

will not trusting the meter on radio persay.. i did the neutraliz with a xtern watt meter. got her stable at around 80 watts on 50.125. thats fine for now. and thats with the old 6146A's that were in it. that i resoldered the tophat on .. darn thing is just slidin rite along. friend is goin to post video of how i sound form his side.. ill post link for it .. also when he spoke from my side. video will be posted for those who like to see.

https://youtu.be/RZjpQ8bCLec (https://youtu.be/RZjpQ8bCLec)


Title: RE: 6146??? 6146B - w
Post by: G3RZP on September 12, 2017, 01:49:21 AM
One point to note with all the 6146 family is that the specification allows for given plate, screen and bias voltages for the plate current to vary over approximately a 2:1 range. So if the tubes are not matched, you could set the bias for 50mA for two tubes and in the extreme, have one tube drawing 16.6mA and the other drawing 33.2mA. Tubes from the same batch tend to match reasonably well, which is how you get away with it in manufacture, but it is not quite so easy these days to find tubes from the same batch.


Title: RE: 6146??? 6146B - w
Post by: W1BR on September 12, 2017, 01:08:46 PM
One way to check neutralization quickly is to see if the plate dip (when tuning the plate) coincides with maximum power output.  If power out increases either side off of resonance--the lowest plate current dip, it might indicate the neutralization is incorrect.  Just a tip for the future.

Pete


Title: RE: 6146??? 6146B - w
Post by: G3RZP on September 13, 2017, 01:00:04 AM
 I basically agree Pete, but there can be a problem in that most rigs measure cathode current and the dip in plate current corresponds to a peak in screen current: especially if the screen supply isn't well regulated, this can result in misleading answers. Something to be aware of...A lot depends on the ratio of screen to plate currents, so the test is best done at full power where the ratio is greatest.


Title: RE: 6146??? 6146B - w
Post by: KB2WVO on September 13, 2017, 07:48:10 PM
One way to check neutralization quickly is to see if the plate dip (when tuning the plate) coincides with maximum power output.  If power out increases either side off of resonance--the lowest plate current dip, it might indicate the neutralization is incorrect.  Just a tip for the future.

Pete

pretty darn close.. like neddle width.
now to get the 101zd in tune. grrrr... i get almost all bads but 15 i think it was that would oscar on itself..  o will no big hurry with it. probey could use a recap .. and alignment. and and lol


Title: RE: 6146??? 6146B - w
Post by: N2DTS on September 15, 2017, 12:12:36 PM
There are differences between 6146, 6146a, 6146b and 6146w tubes.
You need to adjust the radio to the tube type, mostly the grid circuit as the tubes will have different amounts of capacitance and the grids are in a resonant circuit.
On some radios the preselect knob tunes the grid circuit as they use it as a preselector on RX.

Read the manual carefully. Be aware of the high voltage, turn off and short to ground before touching anything, use insulated tools for adjustments.


Title: RE: 6146??? 6146B - w
Post by: KB2WVO on September 15, 2017, 04:16:43 PM
There are differences between 6146, 6146a, 6146b and 6146w tubes.
You need to adjust the radio to the tube type, mostly the grid circuit as the tubes will have different amounts of capacitance and the grids are in a resonant circuit.
On some radios the preselect knob tunes the grid circuit as they use it as a preselector on RX.

Read the manual carefully. Be aware of the high voltage, turn off and short to ground before touching anything, use insulated tools for adjustments.
i need to learn the inereds of tubes. as i will be goin thru the radio down the road for a tune up and such.



Title: RE: 6146??? 6146B - w
Post by: AK0B on September 29, 2017, 09:24:17 AM
6146 series of tubes are very sensitive to gird current.  I love the them but have destroy several by over driving the grid.  I no longer use them for that reason.  I seem to remember 2 ma would give full output on CW.

Stan ak0b


Title: RE: 6146??? 6146B - w
Post by: KB2WVO on September 29, 2017, 04:16:07 PM
6146 series of tubes are very sensitive to gird current.  I love the them but have destroy several by over driving the grid.  I no longer use them for that reason.  I seem to remember 2 ma would give full output on CW.

Stan ak0b

what do you use in place of them?

and the radio is very hard to set... seems only about 80 to 90 watts out. so more to read in manual and check. it is a heathkit sb110. manual says check this n that for voltages. they seem on. 105 volt range. doing what the build manual says. thats the highest i can get the voltage. yet it doesnt say if 105 volts is good or not..

this is off the drive tube i think. spot 2 on the plug. if anyone reading knows heathkits.. the 100ohm removed. from the thru cap to the one 6146.

anyone who knows the rite way and more so then manuals. hints tips tricks? votlages so on..
not a lot of videos on the old girl ..


Title: RE: 6146??? 6146B - w
Post by: KB2WVO on September 29, 2017, 10:45:01 PM
wow only .3 on the swr and the radio WOKE up.. full 100 watts..
from a 1.5 on 50.125 to a 1.2 and its barking out 100 watts...

touchy old girl she is... but i love it ...

so i must be learning from the great folks out here a little something..
ty all for the help..

cold , hot or BOG to all.. 


Title: RE: 6146??? 6146B - w
Post by: K1DA on November 21, 2017, 05:45:24 PM
Glen Zook wrote a fine article called "The 6146 family of tubes" which can be found by Google.   In some radios, like the early S lines the "B" is not a direct replacement.


Title: RE: 6146??? 6146B - w
Post by: WA4JQS on November 22, 2017, 01:16:37 PM
YES  the read write up from Glen. Glen and I talked about this years ago. a lot of old tube radios would not let you do a direct replacement from 6146-/A to the B tube line. the W ruggizied  tubes caused problems in a few of the rigs. Collins rigs were picky if i recall. I had trouble running B's in one of my rigs can not recall if it was the HW 100 or the Swan 250C . there was a lot of talk about this back 25 years ago.
73 Tony WA4JQS / V31SS


Title: RE: 6146??? 6146B - w
Post by: KOP on November 22, 2017, 09:06:37 PM
https://frrl.files.wordpress.com/2008/08/6146tubefamily.pdf (https://frrl.files.wordpress.com/2008/08/6146tubefamily.pdf)


Title: RE: 6146??? 6146B - w
Post by: WA5VGO on November 23, 2017, 08:13:32 AM
This is nothing but urban myth. The 6146B is an exact replacement for 6146 and 6146A. Just take a look at the RCA spec. sheet. Are you going to believe RCA or a internet rumor? I’ve put 6146B’s in dozens of radios that originally had 6146’s. Every one of them worked flawlessly. I’m referring to US manufactured tubes. In the case of off-shore tubes, all bets are off.

http://www.mif.pg.gda.pl/homepages/frank/sheets/079/6/6146B.pdf

By the way, my HW-100 came from Heathkit supplied with 6146B’s.



Title: RE: 6146??? 6146B - w
Post by: KOP on November 23, 2017, 08:52:18 AM
B's in my HW-101, TS-830, Tempo 2020.
      In each case neutralization is important. I've only had one issue with an old tube in the TS-830 when the screen laid over with the predictable screen and cathode resistor failures along with the plate choke up in smoke. This would have happened regardless of what tube variation it was. I've actually never used anything but B's in these radios so I don't  have an idea what the difference would be. 
       I have read about the differences extensively and since I have a glut of B's it's what I use.


Title: RE: 6146??? 6146B - w
Post by: K9AXN on November 24, 2017, 09:10:32 AM
Read the entire tube data sheet for the 6146 and 6146B paying special attention to the operating range of values.  Glen was right --- they are not the same tube but the B version will usually work as a replacement in most radios --- BUT NOT ALL.

When RCA designed the B model, it was to compete with the growing popularity of Sweep tubes used in class AB1 radios.

The precision alignment of the control and screen grids are slightly off in he B model requiring the idle bias of the tube to be increased.  This enables the leveraged increase in output when running AB1 mode.

Net result, if the radio has a wide enough range of bias and neutralizing adjustments --- no problem; provided the operator actually understands neutralizing requirements and techniques.  There are as many techniques as Ham radio folks --- most are SWAG.

Have a great day ----  Regards Jim     






Title: RE: 6146??? 6146B - w
Post by: WA5VGO on November 24, 2017, 02:24:11 PM
"The 6146B/8298A is unilaterally interchangeable with the 6146, 6146A and 8298."

That sounds pretty definite to me.


Title: RE: 6146??? 6146B - w
Post by: K9AXN on November 24, 2017, 07:00:37 PM
"The 6146B/8298A is unilaterally interchangeable with the 6146, 6146A and 8298."

That sounds pretty definite to me.

You read that in the 6146B romance sheet --- who wrote that statement?  Did you read the range of operating parameters? 

I won't repeat the litany of damage reports involving the use of the 6146B in radios that are not designed to use them.  Have you ever heard anyone suggest mixing the 6146B with a 6146 --- that to sounds pretty definite and contradictory to "The 6146B/8298A is unilaterally interchangeable with the 6146, 6146A and 8298".

Have a great day.

Regards Jim 
   


Title: RE: 6146??? 6146B - w
Post by: VK6HP on November 25, 2017, 12:56:14 AM
It may be that there's an element of myth around the topic but it's also clear, if only from the Collins experience, that a tier-1 radio company's line required well-documented and widely implemented modifications to make the 'B' tubes backwards compatible in early serial number radios.  I think there probably is almost "unilateral" compatibility, but it's in the direction of A --> B, not the other direction, regardless of any marketing hype of the day.  That of course assumes the "A" tubes are then operated within their limits.

Perhaps of more contemporary interest is where some of the currently available variants sit on the compatibility list.  For example, I've long wondered about some of the central European vendors advertising Siemens QE 05/40 tubes.  I eventually tracked down some probably applicable German data sheets and it looks to me as if the advertised tubes might be closer to an "A" than a "B" variant, despite one reputable advertiser's by-line.  When queried he acknowledged that this might be the case but, probably correctly, noted he'd had no complaints when the tubes were used in e.g. the Kenwood hybrids.  Maybe it's another example of essentially 6146A-->B compatibility, with power limits respected.  Perhaps some European readers might have more direct knowledge of the 05/40 claims - were they ever advertised as a direct 6146B equivalent?

I'd be very interested to hear of any experiences with the Siemens tubes, particularly in terms of neutralization and sustainable power output.  Until now I've collected NOS RCA or similar but they are getting rarer and the German tubes look more plentiful.  

73, Peter.



Title: RE: 6146??? 6146B - w
Post by: G3RZP on November 25, 2017, 02:17:54 AM
Other than matching tubes or separate bias adjustments for each or just ignoring the problem, what is suggested for the 2:1 range of plate current between tubes possible at fixed bias?

see: http://frank.pocnet.net/sheets/079/6/6146B.pdf on then bottom right of page 3.

This range is much the same for all the 6146 family.


Title: RE: 6146??? 6146B - w
Post by: VK6HP on November 25, 2017, 03:19:23 AM
Well, those are all valid coping mechanisms :)  I guess you could add choice of a circuit topology where matching is somewhat less critical, such as parallel rather than push-pull.  I must say that I have not personally observed anything like a 100% anode current variation across known good tubes. In practice, my starting point is to pick a pair of tubes of the same internal construction and which are sensibly close on a quick tube tester run.  I then run them individually in my "spare" TS-830S and check that the bias values and anode currents are OK.  With that done, I've never had a practical issue in achieving good to very good IMD figures in my Kenwood and Collins gear, both of which use parallel PA stages with local feedback.

A few weeks ago my "good" TS-830S started getting very hot in the PA area and, eventually, blew the mains fuse.  It turned out that one of the RCA 6146Bs had decided to let the side down badly and leave the very great fraction of the work to its partner.  I'm sure the single hard-working tube wasn't the greatest in IMD terms but, while I didn't bother to connect the spectrum analyser at that time, the output was certainly not horrible.

The replacement tubes are again RCA types but I'm now down to 1 spare set of those, hence the interest in the 05/40s.


Title: RE: 6146??? 6146B - w
Post by: G3RZP on November 25, 2017, 04:02:38 AM
When I get around to doing it, I'm going down the separate bias pot route for each valve, especially as the FT102 has three of them. My remaining other 13 valves show a 2:1 variation between them. Fortunately, at one time, I had a practically limitless supply of 6146Bs.......


Title: RE: 6146??? 6146B - w
Post by: KM1H on November 26, 2017, 03:25:46 PM
Ive mixed around most of the 6146 family and the Kenwood supplied Japanese S2001 in TS-830's without anything more involved than a neutralization tweak.

I do run them at 100W, and not balls to the wall like a CBer, and the IMD is more than reasonable.

The hybrids are notorious for the carbon composition resistors in the cathode and screen circuits becoming way out of spec, something the general tube swapper does not realize.

Carl


Title: RE: 6146??? 6146B - w
Post by: K9AXN on November 27, 2017, 10:59:04 AM
Both the TS-830 and FT-102 implement two stage feedback.  The TS-830 also uses progressive swamping for the lower bands.

I believe the FT-102 states an IMD# of -40db and the TS-830 -35db which can be attributed to the two stage feedback design.  That forgives a good portion of the linearity hit when using mismatched or different models of the 6146 at reduced power. 

The single stage feedback in the other radios doesn't have that advantage; they rely on the negative feedback from band to band neutralization which has only a fraction of the effect that two stage feed back provides.

There is one statement in the tube romance sheet that's calls into question the validity of the document; the max Plate to CG capacity is said to be .22pf for both tubes.  Have you ever replaced a pair of 6146's with 6146B's and not had to dial in more neutralizing capacity and bias?

It's easy to say that I stuck B's and all sorts of variations in my radio and they work just fine; but there's a lot of radios out there that were not designed with that latitude of variation.  The users of those radios may not be capable of making the changes necessary to accommodate those tube variations.

   


Title: RE: 6146??? 6146B - w
Post by: G3RZP on November 29, 2017, 03:34:08 AM
I've changed a pair of 6146Bs from RCA with another pair of RCA 6146Bs from a different date code and re-neutralisation was not absolutely necessary - it didn't oscillate - but highly desirable.

Looking at the ARRL test results, the levels of IMD from the TS830 and the FT102 really stand out as being so much lower, especially on the high order IMD, than the solid state rigs that followed them.


Title: RE: 6146??? 6146B - w
Post by: AB1MN on November 30, 2017, 06:40:56 AM
Hi All,

While a bit off topic, but relevant I think. I recently replaced a pair of 12DQ6b tube in my Hallicrafters SR-150 and found that I could not neutralize the rig with the new tubes (neutralized fine with the old tubes). The problem was that the new tubes (made in Japan) had a somewhat different internal capacitance than the old tubes and the neutralizing circuit did not have enough range to compensate. By replacing the neutralizing cap with one having a greater range I was able to neutralize the rig properly. Clearly, this is not a situation limited to 6146s.

The reason that I think this is relevant is that there are likely differences in the internal capacitance among the tubes in the 6146 family and the neutralizing circuit in some rigs may not be able to accommodate the difference . Other than this, I tend to believe that one can use any of the 6146 variants in most circuits.

I also believe that many problems attributed to neutralization are really other issues. If you can remove the plate and screen voltages and get a proper null at the output of the final amp, the problem probably lies elsewhere and is not a neutralization problem. The method I use for the (preliminary) neutralization is to remove the plate and screen voltages from the final, monitor the output at the antenna jack (I use a wideband scope, but one could use a VTVM with an RF probe) and adjust the neutralizing cap for minimum feed through while in tune mode. This procedure is well described elsewhere and I won't repeat the details here.

Assuming the final neutralized properly with a good null but instability still exists one might consider the possibility of parasitic oscillations (the resistor in the parasitic chokes may have opened up or increased so much in value that is no longer damps VHF oscillations), defective or faulty bypassing, layout, or shielding or instability in the driver stage.

Just my 2 cents worth,

Bob, AB1MN


Title: RE: 6146??? 6146B - w
Post by: KM1H on November 30, 2017, 01:26:06 PM
Quote
I've changed a pair of 6146Bs from RCA with another pair of RCA 6146Bs from a different date code and re-neutralisation was not absolutely necessary - it didn't oscillate - but highly desirable.

In the late tube years RCA was known to throw quality out the window including RX, sweep, and power tubes. National Radio had been all RCA from the late 30's and finally dropped them in favor of Sylvania and Telefunken.....no more erratic specs and failures.

On another note I tried a a GE and RCA 6146B in my HT-32B (original specs were for 6146's which were down to 70W) this morning and all was well after a minimal neutralizing cap tweak.

The B is also in several other rigs here from DX-60B, Ranger, Viking II, Valiant, Elmac AF-67, as well as several brands of 2 way FM radios when I helped out a friend with the repairs in his 2 way shop.

Carl


Title: RE: 6146??? 6146B - w
Post by: KM1H on December 02, 2017, 06:08:24 PM
Typo corrected:

National Radio had been all RCA from the late 20's and finally dropped them in favor of Sylvania and Telefunken.....no more erratic specs and failures.


Title: RE: 6146??? 6146B - w
Post by: WY9C on December 09, 2017, 10:33:16 AM
I dont know my way around this web site but I read where the 6dk6 tubes could be used in place of the 6146s. I cleaned out some buildings this year and have thousands of tubes. I have an old Palimar 150 bi linear amp that I was thinking about putting a couple of these tubes in but I do not remember enough about these old rigs to know what I am doing. If you or anyone needs tubes of any sort let me know. I might have them. Text me at 765-363-0338. WY9C.


Title: RE: 6146??? 6146B - w
Post by: VK6HP on December 10, 2017, 04:10:54 AM
I'm guessing you mean a 6KD6 TV sweep tube, since a 6DK6 is a small-signal tube.  6KD6s and 6146s were used in amateur RF power amplifiers but that's about where the similarity ends. The bases and operating requirements are quite different.  However, if you have a stock of 6KD6s you might find they are attractive to collectors of older transceivers from the 60s and 70s.  My old Yaesu FTDX-560, like a number of similar radios of the era, uses a couple of 6KD6s in the PA. Despite a big CW output, the intermodulation performance is pretty terrible and I don't think you'd find anyone throwing out their e.g. Collins 6146 PAs to use a 6KD6-based radio, at least at the power output such radios were advertised.


Title: RE: 6146??? 6146B - w
Post by: KM1H on December 10, 2017, 06:29:53 PM
Quote
Despite a big CW output, the intermodulation performance is pretty terrible and I don't think you'd find anyone throwing out their e.g. Collins 6146 PAs to use a 6KD6-based radio, at least at the power output such radios were advertised.

Im partial to TS-830's with their longevity and superb 6146 IMD.

At one time I had a pair of Drake C Lines using 6JB6's, short life since I operated all over 6 bands contesting and chasing DX and a lot of retuning didnt help. A muffin fan on top of the final cage brought life from about 6 to 18 months.

Carl


Title: RE: 6146??? 6146B - w
Post by: VK6HP on December 10, 2017, 11:07:17 PM
Carl,

After a severe existential crisis I did manage to part with a TS-530S hybrid which I'd restored - just in order to get some much-needed shelf space.  But the two TS-830S transceivers, one of which was going to be a donor radio before I couldn't help myself and brought it back to full health, are both going strong.  They are immaculate cosmetically and I've fitted 1st and 2nd IF CW filters in both. For various reasons I recently used one of the 830s as a primary radio for a few weeks, and it was fun to run the test gear over it and remind myself of just how well it works.  There's indeed not much to touch it terms of PA cleanliness and I'm going to a fair bit of trouble and expense to do as well with a forthcoming SDR transceiver and LDMOS amplifier.

I do sometimes use an audio DSP filter on the 830 receiver output, just to knock some of the urban noise down.  But with good receiver operating practices, judicious use of the notch and passband tuning, and the processor between the ears, a lot can be achieved.  Listening during the recent worldwide CW contest I used an 830 alongside my TS-590S and I concluded that the 590 had the edge - but not by much, and about half the time largely due to the Kenwood 'NR2' CW noise reduction algorithm.  I guess there has to be something to show for 35 years of progress.

73, Peter.


Title: RE: 6146??? 6146B - w
Post by: KM1H on December 12, 2017, 01:00:35 PM
Peter, I have 4 TS-830's, all have a full slot of CW and SSB filters plus several mods to minimize filter blowby and improve 15-10M noise figure.

Three replaced a couple of TS-940's which had excessive TX and RX phase noise even after several mods to be really useable for weak signal and very low external noise VHF to microwave work with transverters. Another mod was to add outboard Jackson Brothers 10:1 reduction drives as I found the 25 kHz per revolution intolerable.
The last one lives on the amp repair and 6M conversion bench where amp problems wont blow up anything plus I give all repairs a good workout for a day or so before shipping back. A very modified 60's transverter covers the 6M side at 50-140W.

The newest rig I have is still old, a TS-950SD. After trying just about everything available and find them wanting, including SDR so far, Im in no hurry to change any longer....I'll be 77 tomorrow :o ::)   

Carl


Title: RE: 6146??? 6146B - w
Post by: HAMHOCK75 on December 12, 2017, 11:47:32 PM
Happy Birthday KM1H!!!


Title: RE: 6146??? 6146B - w
Post by: VK6HP on December 13, 2017, 02:58:13 AM
The tuning rate is a funny thing, Carl. I got along fine when using the 830S as my main radio, but it annoys me when I have to mix and match with other radios.  I have two VFO-230s which I use for routine HF work and I might get around to doing the tuning rate modification on those.  But they do detract a little in terms of phase noise, of course.

Having been away from amateur radio for a good number of years, I have a "missing link" period from the 830S era until a couple of years ago, so the 940 and their contemporary's issues passed me by. I've enjoyed the journey back into the hobby and am heading, cautiously and critically, into the SDR/LDMOS era, while keeping my interest in the older gear.

Happy birthday - and we must be close to sharing a birthday.  I have a decade rolling over tomorrow and figure I'm now officially OK with the grumpiness. Might even be obligatory ;)

73, Peter,


Title: RE: 6146??? 6146B - w
Post by: K1DA on December 13, 2017, 03:00:30 PM
The Glen Zook article is well worth reading.  He ran a large factory authorized Motorola shop at a time when
many of the VHF products had 6146 or 12 volt filament variants of the tube  as power amps. Was  was also chosen to rehab KWM 2s left over from the  Vietnam era for the first Gulf war.  To dismiss his observations as an internet rumor is a classic example of Dunning-Kruger syndrome. 


Title: RE: 6146??? 6146B - w
Post by: WA5VGO on December 13, 2017, 03:32:25 PM
"Was  was also chosen to rehab KWM 2s left over from the  Vietnam era for the first Gulf war."

KWM-2's were serviced by Dennis Brothers, not Glenn Zook. And that's not the only thing you're mistaken about.


Title: RE: 6146??? 6146B - w
Post by: K1DA on December 15, 2017, 06:57:19 AM
You're making it up as you go along, Sparky, Mr. Zook writes of the trailer load of M2s which showed up at his company when he agreed to do rehab work for the military.  Calling him a liar are you?  That's a Dunning Kruger tipoff.  Whatever you do, DON'T read his article on the 6146 family,  it's always best to comment on things you haven't read, right?


Title: RE: 6146??? 6146B - w
Post by: K8BYP on December 15, 2017, 01:22:56 PM
"replacing the neutralizing cap with one having a greater range I was able to neutralize the rig properly. Clearly, this is not a situation limited to 6146s."

yes, not limited to 6146. Neut capacitance is a function of Miller capacitance which is a function of (A+1) (gain plus 1) and with a different Miller capacitance, the neut cap wasnt the correct range.

Its not so easy to get small HV air variables at a wide range..


Title: RE: 6146??? 6146B - w
Post by: K9AXN on December 16, 2017, 09:08:08 AM
Dave,

Your story along with a large number of others having to increase the value of the neutralizing capacitor and the neutralizing capacitor melting in the Collins radios when using the 6146B would seem to confirm the tube data sheets are incorrect for the 6146B.

The data sheets claim that the Plate to grid capacity is .22pf MAX for both the 6146 and 6146B.  If you take six 6146's and six 6146B's and insert them in your radio, the neutralizing feedback and bias required collectively will be higher for the B version. 

The 6146B was deliberately designed to compete with sweep tubes especially in class AB1 mode.  What do you do to a beam type tube to accomplish this.

Use different diameter wire for the screen or control grid or slightly misalign the SG and CG.  The misalignment happens in the production of beam type tubes without exception.  That is what causes the 2/1 range of operational values and the need to hand pick matched pairs.  The higher the bias required, so to will be the achievable increased output in AB1 mode ---- but so to will be the CG to P capacity. 

Glens observations were correct.

Have a great day Dave. 

Regards Jim       


Title: RE: 6146??? 6146B - w
Post by: KM1H on December 16, 2017, 12:14:55 PM
There is a lot more than simply reading a spec sheet and stumbling blindly ahead in amplifier design. Collins and Motorola were far from technical leaders with the 6146/6146B interchangeability while many more companies had no to minimal trouble.

Matched pairs was not necessary for most products and the 2:1 issue is at the extreme edge of a bell curve and when US tube manufacturers were building thousands of quality tube the majority were well within the middle. RCA started the migration to garbage quality but one person has tried to convince everyone it was a never shall the two meet compatiblity issue to start with which is PURE BS. I use that "paper" as an example of Hammy Hambone at its worst.
K1DA made a good point to remember.

Carl


Title: RE: 6146??? 6146B - w
Post by: K9AXN on December 16, 2017, 01:04:21 PM
There you go again partner, take it easy you should take a nap and read a good book.

A good day to you --- your friend jim    


Title: RE: 6146??? 6146B - w
Post by: KM1H on December 16, 2017, 01:22:42 PM
Quote
There you go again partner, take it easy you should take a nap and read a good book.

A good day to you --- your friend jim 

Still cant take anyone not in lock step with you I guess and have to resort to insults; no surprise you havent changed over the decades, it is sad also.

You are no friend of mine either.


Title: RE: 6146??? 6146B - w
Post by: K9AXN on December 16, 2017, 03:08:59 PM
Carl, it wasn't an insult.  Also, I wish you a happy birthday.

Regards Jim


Title: RE: 6146??? 6146B - w
Post by: KM1H on December 16, 2017, 05:09:53 PM
Just go away Jim I dont believe you and want nothing to do with you..OK, got it?


Title: RE: 6146??? 6146B - w
Post by: K9AXN on December 16, 2017, 05:45:37 PM
Just go away Jim I dont believe you and want nothing to do with you..OK, got it?

Carl, No I don't got it!  I was simply trying to find a way to have a friendly conversation with you.  If this can't be done I would suggest removing me from your read list and cease writing sarcastic comments to my posts.  I won't be going anywhere soon and will continue to submit material to this and many other lists.

Have a good evening

Regards Jim


Title: RE: 6146??? 6146B - w
Post by: KM1H on December 16, 2017, 06:11:07 PM
You have never had a friendly conversation with me and many others, just syurpy words to mask your deviousness and hate when ANYONE dares to question you and/offers alternative comments.
The real you is very transparent.

Stop the "have a great day" or similar phony comments when replying to me, they make me want to barf.



Title: RE: 6146??? 6146B - w
Post by: G3RZP on December 17, 2017, 02:25:48 AM
Transmitters that I designed were made in sufficient quantity to have used about 9,000 6146Bs, while those done by colleagues used about another 6,000. Generally speaking, tubes from the same batch matched reasonably well when new, but mixing batches could give problems, and separate bias controls for each tube made life much easier. Especially for a marine radio that might need work doing on it in some small fishing village where spares are hard to come by.

'Used' 6146Bs that still meet spec on RF output power can have a wide variation - I have measured plate currents of 4 to 28 mA over 13 of them, all except 2 with different date codes. Those two with the same date code matched reasonably well.


Title: RE: 6146??? 6146B - w
Post by: K9AXN on December 14, 2018, 10:19:38 AM
The following url contains information that may help to explain the differences in the 6146 tube family.

http://k9axn.com/_mgxroot/page_10935.html

It should help to decide what tube to use in what class of service and what benefits and risks are involved.


This post does not suggest that you choose any specific course of action; it simply provides factual data and time lines to make common sense choices available. 

A Merry Christmas and Happy Holliday season to you!

Regards Jim K9AXN
       


Title: RE: 6146??? 6146B - w
Post by: KD0REQ on December 15, 2018, 08:48:36 AM
neutralization of the finals in most rigs will drop the output slightly at 10 meters due to feedback. I would try another driver tube. if that doesn't do it, there might have been Golden Screwdriver visits to the band coils, and it's worth considering a realignment.


Title: RE: 6146??? 6146B - w
Post by: K1DA on December 30, 2018, 11:52:26 AM
Google "Glen Zook  The 6146 family of tubes"   One tidbit is that a 6146W could be a 6146B.   They have a bit higher gain and the neutralization circuits of some early S Lines could not keep them stable on the higher bands.  I stick with 6146A tubes in mine. 


Title: RE: 6146??? 6146B - w
Post by: G3RZP on December 30, 2018, 02:29:45 PM
Quote
One tidbit is that a 6146W could be a 6146B.

Not if you believe the RCA data sheet.....or the Mazda Belvu one.


Title: RE: 6146??? 6146B - w
Post by: WA5VGO on December 31, 2018, 07:17:37 AM
I get my information from the manufacturer’s data sheets. Never had a problem.

Darrell


Title: RE: 6146??? 6146B - w
Post by: KAPT4560 on December 31, 2018, 10:03:48 AM
 The nostalgickitscentral website has some Heathkit service bulletins about tube brand/suffix/build date problems. I have incorporated some of the bulletins to improve performance.
 https://www.nostalgickitscentral.com/heath/heathkit.html


Title: RE: 6146??? 6146B - w
Post by: KX4OM on December 31, 2018, 04:38:31 PM

......

The 6146B was deliberately designed to compete with sweep tubes especially in class AB1 mode.  What do you do to a beam type tube to accomplish this.
.....
Regards Jim       

Which sweep tubes, exactly? I haven't seen that in the literature.

Ted, KX4OM


Title: RE: 6146??? 6146B - w
Post by: G3RZP on January 01, 2019, 02:43:06 AM
Back in 1953 when the 6146 first appeared, there were very few (if any) commercial amateur rigs using sweep tubes. Most used 807s at that power level, one reason being that they and the 12 volt version, the 1625, were extremely cheap because of the number of WW2 surplus ones around. Some early post war TV sets in the UK even used 807s in the horizontal sweep function because of the low price.


Title: RE: 6146??? 6146B - w
Post by: KD0REQ on January 01, 2019, 08:44:21 AM
I always thought the 6146 was a higher power upgrade of the 2E26 for a larger market.


Title: RE: 6146??? 6146B - w
Post by: K9AXN on January 01, 2019, 06:17:21 PM

......

The 6146B was deliberately designed to compete with sweep tubes especially in class AB1 mode.  What do you do to a beam type tube to accomplish this.
.....
Regards Jim       

Which sweep tubes, exactly? I haven't seen that in the literature.

Ted, KX4OM


When did the 6146B come to market?  Were there any sweep tubes available and for how long?  Both the low and high power sweep tubes were integrated into ham gear.  Exactly what are you asking??

     


Regards Jim


Title: RE: 6146??? 6146B - w
Post by: K9AXN on January 01, 2019, 06:50:12 PM
Back in 1953 when the 6146 first appeared, there were very few (if any) commercial amateur rigs using sweep tubes. Most used 807s at that power level, one reason being that they and the 12 volt version, the 1625, were extremely cheap because of the number of WW2 surplus ones around. Some early post war TV sets in the UK even used 807s in the horizontal sweep function because of the low price.

Interesting info.  History is full of surprises. 

Regards Jim


Title: RE: 6146??? 6146B - w
Post by: KX4OM on January 03, 2019, 02:56:33 PM
Jim,
What I am asking is what is your source for your statement about 6146B tubes were being designed to compete with sweep tubes, (especially in Class AB1 mode.)

The Kenwood TS-520 came with the Japanese equivalent of the 6146A, the


Title: RE: 6146??? 6146B - w
Post by: KX4OM on January 03, 2019, 03:43:10 PM
Darned tablet, I hit send prematurely by accidentally. Then I couldn't type fast enough in "modify post" to add more. Short version is that I think the land mobile, military and industrial markets drove the enhanced 6146B development. By the time new rigs like the Uniden/Tempo 2020 (I have one) and the Yaesu FT-101 ZD were made, they used the Japanese equivalents to the 6146B, as did the Kenwood TS-530S, which I had. Galaxy kept on producing their twin-tube sweep tube PA rigs, topping out with the GT-550 at 550W PEP input. I have a working Galaxy V Mk2, and retired V Mk3 and GT-550.

Ted, KX4OM


Title: RE: 6146??? 6146B - w
Post by: K9AXN on January 03, 2019, 07:03:39 PM
Darned tablet, I hit send prematurely by accidentally. Then I couldn't type fast enough in "modify post" to add more. Short version is that I think the land mobile, military and industrial markets drove the enhanced 6146B development. By the time new rigs like the Uniden/Tempo 2020 (I have one) and the Yaesu FT-101 ZD were made, they used the Japanese equivalents to the 6146B, as did the Kenwood TS-530S, which I had. Galaxy kept on producing their twin-tube sweep tube PA rigs, topping out with the GT-550 at 550W PEP input. I have a working Galaxy V Mk2, and retired V Mk3 and GT-550.

Ted, KX4OM


Ted,
Please review the following url:  http://k9axn.com/_mgxroot/page_10935.html , the story and timeline and look at the visible and infrared signatures of the various tubes.  One thing that is not included is the FAA 6146W which was a super hardened 6146 that I believe you had purchased several of, encountering trouble.  When you say the 6146B equivalent, it generally speaks to the RCA 6146B and it's claim to being "Unilaterally replaceable for the earlier 6146's" --- it's not so and as Glen stated they rescinded the statement.  The RCA 6146 family that were built after 1963 are Sylvania technology for the heater and tube characteristics but the plate was not enhanced --- they simply stated that the tube temp could be run 40C higher from 220C to 260C    The Matsushita S2001A is also Sylvania technology but further improved.  The url above will divulge the details.  As for sources, the paper above speaks for itself or USN NSD ESO Great lakes Sylvania and RCA vendor interviews and personal testing of the Matsushita S2001A.


Read the url --- should answer all of your questions.  There is more detail to the story but still looking through the archives for notes.


Hope you had a Merry Christmas and Happy New Year!


Regards Jim




Title: RE: 6146??? 6146B - w
Post by: K3UIM on January 04, 2019, 07:50:47 PM
heres a video.. if anything you like to see to help give a idea.. let me know. ill try and do a video for it..
these same valves.. 6146W's in a 101ZD show about 50 watts on 10m and 100 watts on 75m... no idea if it helps....the 6146A's that been in radio for over 20 plus years are only giving about 35 watts on 6m...
 
https://youtu.be/ARlLnCEvrQY (https://youtu.be/ARlLnCEvrQY)
I may be out in left field, but it looks like your meter comes to rest below the zero point with the rig "off". Perhaps if you zero the meter at rest, you'll get a more accurate output reading.
Just my 2 cents.
Charlie, K3UIM


Title: RE: 6146??? 6146B - w
Post by: KX4OM on January 09, 2019, 07:27:11 AM
I'm wondering where the GE tubes fit in all of this, design-wise. If I remember correctly, the K9STH document addressed the issue of Heathkit and the integrating of the 6146B, labeled as a 6146A.

Also, series connection of different versions: the tubes would have the same current in the filaments, with different voltage drops if the resistances were different. How about if they were connected in parallel? The tubes would have different filament currents with equal voltages. It seems to me that either would be bad.

Ted, KX4OM