8950 tube ??

[AALmachineandtool]

I have been doing some researce,and I see if not mistaken. I can take a 8950 tube and exchange the heater pins 1 & pin 12 from the socket,and place a 6lf6 in and use it in place of the 8950! 6LF6 is just a broke down verson of the 8950 but at 6 volts........any thoughts

The 8950's and the 6LF6's both use the pin configuration 12GW from the ARRL radio amateur handbooks. The 6KD6's are an analogue to these tubes as is the Maco M-2057. The 2057 and 8950 have 12 volt filaments, while the remaining tubes have 6 volt filaments. The pin-out schematics are the same.


Pins 1 & 12 are the filament pins. The 12GW schematic has the grid/screen and suppressor pin-outs. The other tube differences are the plate capacitance figures. You may have to manipulate the loading coil, as well as the tune & load capacitance values. Otherwise, it's an easy swap. The 8950 and the 2057 are more scarce than the 6KD6's and 6LF6's. The cost will be higher.

 

[AudioShockwav]

They have become extremely expensive.
Often the tubes are 3x the worth of the Amp.

73
Jeff

 

[lonestarbandit]

I used to think the 6LQ6s were expensive 10 years ago when I had my tubers. Wow!

 

[AudioShockwav]

I remember when my 300a needed tubes and I went to Thrifty Drug store to test them on the floor model tester.
It's been too long but I think we payed $9 bucks for new 6lf6 tubes.
I used to throw away anything that tested below 70%.

There used to be a old Air Force reserve base north east of Madera CA.
When they de-commissioned it they tossed cases of tubes like the 811 and sweep tubes into the land fill and buried them.
I saw wooden bins of surplus radio equipment sold at a auction......

73
Jeff

 

[nomadradio]

Often the tubes are 3x the worth of the Amp.

Just means that for every person looking for an amplifier, there are three people looking for tubes.

73

 

[jtrouter]

Just means that for every person looking for an amplifier, there are three people looking for tubes.

73

So friends and my wife think i am crazy, I have been looking for 8950's and 6LQ6's and a few others for the last ten years or so. I have 24 of each enough that will last my lifetime and more for my collection of sweep tube amps that i have and keep on buying. It is a bad? habit that i have from my early days of CB going back to my first tube amp that i bought new in 1976. Say what you want about sweep tube amplifiers but i do know that my signal is as clean as possible. IF you send a clean signal into a good amplifier design EVEN using sweep tubes. Run it correctly it is amazing how (clean) they can be. Verified using a spectrum analyzer a proper tuned radio and amp together not only does it sound great everyone around me appreciates it too. Now thats what i call a win-win.
Merry Christmas and Happy Holidays to all of my Worldwide DX radio family.