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What are you using to substitute 1614 mod tubes in Ranger I with no mods? Best results?

Because of voltage ratings, you can use 6L6GC (not 6L6, 6L6G, 6L6GA or 6L6GB).
I used Russian 6550s in mine as well (the old coke-bottle 6550s won't fit)
1614s were a higher voltage version of the metal 6L6.

Good luck.

I'm not sure there is any real difference in ratings.  I seem to recall that they are nothing more than metal 6L6s that passed certain more stringent QC standards than what was acceptable for the standard 6L6.

I'm going to have the same concerns for spares for my Gates BC-1J since it uses 4 of them in the audio driver. I did find this little piece on the web...

http://www.tubecad.com/december2000/page19.html

"The difference between the 6L6 and the 1614 span two ratings systems: design-center to design-maximum and design-maximum to absolute maximum. If the tubes were really the same, the 1614's ratings should be 20% higher than the 6L6's. The power is only 10% higher, the plate voltage is 4% higher, but the screen dissipation is 40% higher. The ICAS ratings are quite a bit higher, except for the screen dissipation.

The 1614 is basically a selected 6L6 intended for class-C RF amplifier use. Its CCS and ICAS ratings are based around this type of usage, hence its different-than-expected ratings. In a sense, the difference between a 6L6 and a 1614 is in the ratings, not the tube itself."

There's a chart at the link with the various ratings.
   
   
      

Also the data sheet on the 1614...

http://tubedata.tigahost.com/tubedata/sheets/049/1/1614.pdf

How about using NOS 5881s or current production Russian/Sovtek 5881s as substitutes?

I believe the pin-out is the same as the 6L6 family of tubes, and the 5881 was also nomenclatured as the 6L6WGB at one time.

Small-sized envelope, and a durable and rugged tube.

N0WEK; I think the Gates "Twin-Drive" audio driver circuit in the BC-1J used 5881s interchangeably with 1614s and 1622s in production.

73,

Bruce

I totally agree. Every 1614 I have ever seen is clearly marked "6L6" around the base crimp.

Darrell, WA5VGO

Otoh, I have heard that the 1614 can be run upside down in a liquid cooling bath... this may be urban legend, or not...

              _-_-bear

That will work with about any tube without a cap on top.  My very first modulator used for the audio driver a single 6AQ5 inverted into a glass of water.  Otherwise, after a few minutes it would heat up and the audio would become (more) distorted.

I forget, was the envelope tied to one of the pins in those?

It's all about voltage ratings. The plate voltage in the Ranger I runs around 550, with solid state rectifiers a bit over 600 volts on the modulators and 6146.

According to the RCA HB3 data sheet for the 1614 dated 12/1946, the tube is called a "Transmitting beam power amplifier". In ICAS AB1 modulator service like the Ranger's, the 1614s max plate voltage rating is 550 volts for 50 watts of audio outpoot.

In the same RCA HB-3 dated 11/1954..6L6 and 6L6G, the max rated plate voltage in AB1 is 360 volts. Max power out at 360 volts is 26.5 watts, nowhere near enough to plate mod a 6146. OTOH, the 6L6-GC is rated for a max of 500 plate volts, it's a completely different animal than its predecessors.

The Johnson engineers selected the proper tube by the book for the Ranger I modulator.

In the Ranger II they switched to a 7027 modulator tube, a 'super' 6L6 variant which had a maximum Ep or 600 volts.

A pair of 7027s would make a great replacement for 1614s, too. The pinout is similar to the 1614/6L6.

I have used:

Metal 1614
Metal 6l6
Glass 6l6
glass 6l6gc

All with about the same results.  They will all work just fine. 

For more audio power, Try some 8417s but you must change the bias a bit.  I had a pair running 150 % mod,  Later removed them and put the rig back to stock. I got worried the iron would fry.

C

I used the Sovtek KT88/ 6550's and they worked great without any mods whatever in a Johnson Ranger. The pin out is the same. I got 150 percent pos peaks too. The rig as far as the power supply is concerned was solid stated and the audio driver transformer was removed in favor of a phase splitter.

The only thing dumb that I did twice was put my hand on operating 1614 tubes and the envelopes were at plate potential due to a carbon path.

It was interesting to compare the data sheets, 6L6, 1614, 6L6GB, 6L6GC, 807, AND 6146.

Seems that tuvbes listed for RF Amp service would have heater to cathode ratings included. note worthy is that the 1614 had the highest rating. perhaps they were selected for seom special RF amp service that needed the higher cathode to heater rating. Perhaps cathode wobulation. hi

From time to time I've seen adapters that have a socket and a plate cap and take a 6bg6 and convert it into a 6L6.

From a cost perspective, 6bg6's seem to be lowest of all the 6L6 equivalents. Plus they will take a higher plate voltage like an 807 (due to the plate cap).

The adapters might make the combination too tall for a Ranger -- don't know about that.

Don, the idea is/was that the metal was a fairly efficient thermal conductor, the glass not so much... and the temp differential on two sides of a glass envelope will cause cracking... but I don't remember if the metal tubes had an inner glass envelope with the metal outer or not. But anyhow that is what I heard or read, put it in liquid cooling and let it rip...  ;)

                      _-_-bear

There are two versions of the 6BG6, the newer ones had more scrot. The metal tubes have a glass liner inside. I wonder how the plates differed from metal to glass. Me thinks the metal ones had to be different for work at RF.

The 6L6 and 1614 have pin 1 connected to the outer metal. It is amusing if the designer of the amp or whatever has used it as a tie point.
The 1614 is rated for full input to 80MHz.