8950 / 6LF6 / 6MH5 / 6LB6 / Etc

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KC4VWU:
Shane, you must have a boatload of 8950's. That's the very reason why I gave up on the Swans and such. I can easily get a good pair or three 4-400's for the price many dealers want for those sweep tubes.

I was thinking of building a multiband sweep tube amp just to get a little extra "ooomph" for the PW tx's I like to play with. But after a lot of reading and thought, I've pretty much gave up on that idea. I was thinking of using the cheaper, higher heater voltage tubes such as 31LQ6, 31JS6C, 35LR6, 42KN6, etc; there are quite a few more. BTW, not to be advertising here but since we're on the subject, I have quite a few NOS sweeps that I would like to sell; mostly the higher heater voltage ones.

If your really determined though, have you ever given consideration to the 6KN6? You could buy approximately 6 NOS ones to one 8950.

I see nothing wrong with experimenting, that's what we're supposed to do.

On the Messenger I conversion, I have several here that maybe someday I'll get to play with and I've contemplated that (band change) before. A neighbor, Mike KF4QKR, has converted one to a 75M transmitter and has been using it for several weeks now. He has posted about it here a week or so back.

Phil

K4TLJ:
Some not all 6LB6 are in fact 8950 with a six volt heater. You have to examine the tube elements and base connections. I have a box of various 6LB6 and there are differences. The two Westinghouse labeled tubes are identical to 8950 tubes. The GE labeled tubes are missing the curved shield around the plate lead and some do not have the double base pin connections for the screen.

KD6VXI:
Quote from: K4TLJ on October 23, 2009, 05:21:54 PM

Some not all 6LB6 are in fact 8950 with a six volt heater. You have to examine the tube elements and base connections. I have a box of various 6LB6 and there are differences. The two Westinghouse labeled tubes are identical to 8950 tubes. The GE labeled tubes are missing the curved shield around the plate lead and some do not have the double base pin connections for the screen.


I have an actual GE Datasheet to the 8950, and no, it's not identical to ANY other sweep tube, physically.  Electrically, yes.  Physically, this tube has pin 6 tied with pin 2 to the cathode, and was sold, marketed and designed as an RF amplifier tube to 30 mhz.  I was REALLY surprised at this, as I was led to believe the M2057 was the "RF" version of that tube...  Guess it was more a "ruggedized" version...  In any shape, it was made for Maco.

As to do I have a boatload?  Nope, just these two tubes.  BUT, the amplifier is pretty clean, cosmetically, and has original tubes in it.  I DON'T want to kill them, hence me not "fudging" around to find what the impedance on input is.  I've already cherried them once, and my next move was down to here to ask.

Had fun this weekend.  CQWW /mobile.  3 contacts.  Turkey, Japan and Canada..  Next year, I'll be legal limit on 20 and 40 mobile.

--Shane

W3RSW:
Pete said,
Quote

And, on a "serious" note, I've never seen a CB linear that was worth the time and effort to convert over for use on a ham band unless you stripped it down to bare bones first and then rebuilt it using some sound technical logic and components.

Well!
I'm insulted.  ;D

A certain unnamed ham and "()" built a beautiful CB amp way back in the day. A 6JB6 driving a trio of 6LF6's, all four in GG.  Plate tranny from a Link xmitter, meters by Motorola, the finest variables from ARC-5's, ... I mean , you name it we had quality schtufff... 

I'm sure it got burnt up by "ignerant lak of tunin'up" knowledge, but it 'shore was purty. '

We were so worried that we labeled it as the "10 Meter Intensifier."

"()" still has a wierd growth wiping out a fingernail on left had from sticking hand behind rig to pinch final coil for resonance while energized. Um.. yeah, first Darwin moment 'fer shure.'

Detroit47:
Quote from: KD6VXI on October 25, 2009, 09:56:37 PM

Quote from: K4TLJ on October 23, 2009, 05:21:54 PM

Some not all 6LB6 are in fact 8950 with a six volt heater. You have to examine the tube elements and base connections. I have a box of various 6LB6 and there are differences. The two Westinghouse labeled tubes are identical to 8950 tubes. The GE labeled tubes are missing the curved shield around the plate lead and some do not have the double base pin connections for the screen.


I have an actual GE Datasheet to the 8950, and no, it's not identical to ANY other sweep tube, physically.  Electrically, yes.  Physically, this tube has pin 6 tied with pin 2 to the cathode, and was sold, marketed and designed as an RF amplifier tube to 30 mhz.  I was REALLY surprised at this, as I was led to believe the M2057 was the "RF" version of that tube...  Guess it was more a "ruggedized" version...  In any shape, it was made for Maco.

As to do I have a boatload?  Nope, just these two tubes.  BUT, the amplifier is pretty clean, cosmetically, and has original tubes in it.  I DON'T want to kill them, hence me not "fudging" around to find what the impedance on input is.  I've already cherried them once, and my next move was down to here to ask.

Had fun this weekend.  CQWW /mobile.  3 contacts.  Turkey, Japan and Canada..  Next year, I'll be legal limit on 20 and 40 mobile.

--Shane



Shane a M2057 is an 8908 with a 12 volt filament and a compactron base.

73 N8QPC

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