Antique Electronics Supply has been running a "25% off sale" on many NOS vacuum tubes for the summer. They recently added a list of tubes priced at 50% off. I went through the entire list looking for tubes that interested me, and found a few real bargains. The list does contain plenty of tubes that just won't work for audio, or some that I already have too many of, and some that I can buy elsewhere for less even at 50% off. Here is the short list that I ordered and why:
6AQ4 for $5.70. SY and others have proclaimed this a great tube but I have never seen them below $12 each, therefore I have never tried it.
6MF8 for $1.65. Another tube that I have never seen but it looks like an excellent canidate for a spud amp.
6DG6 for $1.70. This is another name for a 6W6. These are capable of operating well below 100 volts, thus can be used for hybrid "super tube" and low voltage amp experiments.
12L6 for $1.13. This is one of Wavebourne's favorites. It will also work well below 100 volts (maybe better than the 6DG6). For $1.13 I can do some "testing" without worrying about blowing up something expensive. They are limiting customers to a maximum of 8 on this tube.
6CB5A for $2.00! I remember this one from my days as a TV repair tech. It was one of the strongest sweep tubes available in the 1950's. It is no 6LW6 but for $2 who cares. Expect some serious testing on these!
Curves look good for a P-P output tube. Screen drive curves look good too.
6AQ4 for $5.70. SY and others have proclaimed this a great tube but I have never seen them below $12 each, therefore I have never tried it.
6MF8 for $1.65. Another tube that I have never seen but it looks like an excellent canidate for a spud amp.
6DG6 for $1.70. This is another name for a 6W6. These are capable of operating well below 100 volts, thus can be used for hybrid "super tube" and low voltage amp experiments.
12L6 for $1.13. This is one of Wavebourne's favorites. It will also work well below 100 volts (maybe better than the 6DG6). For $1.13 I can do some "testing" without worrying about blowing up something expensive. They are limiting customers to a maximum of 8 on this tube.
6CB5A for $2.00! I remember this one from my days as a TV repair tech. It was one of the strongest sweep tubes available in the 1950's. It is no 6LW6 but for $2 who cares. Expect some serious testing on these!
Curves look good for a P-P output tube. Screen drive curves look good too.
Yeah, I know. I started out looking at this list. I looked up each and every number. Then I called the Tube Center to check prices. Then I bought some tubes for experiments from each place. That cost me about $300.
Some tubes are going into projects that I already have planned. Most are for "science." There will be more photos of glowing tubes in the near future.
I bought some surplus Plitron 400 watt toroidal P-P OPT's on impulse last year. How many of those 6CB5's do I need to wire in parallel to wake those things up? At $2 each I can afford to find out.
I better add these into my cart and commitThanks for the heads up, George!!
If you are getting any of these for your own experimentation, go for it. Don't buy them based on my purchases. The only thing that I can guarantee is some glowing tubes, and some smoke! Many of my "educated guesses" don't work out. I have no problem trying experiments with $2 (or less) tubes that I would never try with expensive stuff. I may even sacrifice a pair to find the limits, although the 6BQ6GA's that have been seen glowing like light bulbs are still alive! The $0.98 6BQ6GTB's from AES are not the same and will not take that sort of abuse. I have verified this! I have some more 6BQ6's coming from a different source that will be tested.
My long term plan is to develop a "universal P-P driver board" that can drive anything from a bunch of sweep tubes in parallel, to a pair of 845's, to the usual pair of 6L6GC's - 6550's - EL34's. Screen driven applications will be supported too. Now you know why I have been collecting different sweep tubes with different drive requirements.
Don't forget the dollar sale at RES: http://vacuumtubes.net/
I picked up some 6LU8's and 6JW8's for $1 based on some of your posts.
I picked up some 6LU8's and 6JW8's for $1 based on some of your posts.
Wow, some fascinating tubes there. That 6CB5A looks really nice. A slightly derated 6LQ6 in octal socket for 1/30th the price... what is not to love?
I also note that they have the 6BQ7 for $1.55. Wouldn't that one make a nice general purpose preamp tube for voltage amps and as CFs? How do they perform in the noise and microphonics department?
Man I never have the money to take advantage of this stuff.
I also note that they have the 6BQ7 for $1.55. Wouldn't that one make a nice general purpose preamp tube for voltage amps and as CFs? How do they perform in the noise and microphonics department?
Man I never have the money to take advantage of this stuff.
I have used that one for an LTP phase splitter. It works good for that service. I can't speak for the noise and microphonics performance since I used it at a relatively high signal level. Some TV tuner tubes are purposely designed to have a semi variable Mu. This can cause excessive 2nd harmonic distortion in SE use. The 6ES8 is an example. I did not notice this effect with the 6BQ7. I did not test its cousins the 6BK7 and the 6BZ7 yet.
The 6CB5A is a much older design than the 6LQ6. I first spotted this one in an Emerson color TV from about 1956. I rebuilt the TV in 1968. It was rescued from the trash and was the only color TV in our neighboorhood at the time. There were about 20 people in my room during the lunar mission that was televised in color. Note the difference in specs from the Sylvania and other data sheets. I haven't seen one of these tubes since that TV, but I will soon be "testing" some.
"Why would companies make that many numbers with the same ratings?"
From looking thru the GE handbook, it looks to me like the tube sections are just plucked out of more common twin triodes or single pentodes. They probably just put whatever the TV guys wanted into a bottle for space efficiency. Some are just different pinouts of the same combo too. (6BN11 6V11)
Don
From looking thru the GE handbook, it looks to me like the tube sections are just plucked out of more common twin triodes or single pentodes. They probably just put whatever the TV guys wanted into a bottle for space efficiency. Some are just different pinouts of the same combo too. (6BN11 6V11)
Don
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