Hello, My apologies for the intrusion. but I have a question that I am hoping someone has an answer to. I have never posted to a news group, so again, my apologies if this does not meet the standard protocol.
I have a bunch of Raytheon Subminiature tubes that I inherited from my Father, who was an electronics bugg (I followed a different path) that have code QF-721. In searching the internet I have found a bunch of identical looking tubes such as one labeled CK6088. I have done lots of searches on the internet and I cannot find out anything about these and am wondering if you know about these, or if you can point me to a website that might shed some light on these.
I am considering the possibility of donating these to someone but if I cannot find out what they are for, I cannot imagine how I can find who to donate them to -- perhaps a school or something.
The 7435 looks similar to what you have; it's a detector diode. Most of the 5-lead subminis in this (small) databook are diodes of one type or another, although one or two may be single triodes with indirectly heated cathodes. Almost all of the tube data manuals ever printed are online somewhere; I can't find anything at all about that particular number. One possibility may be that what you have is a part with a "house number" put on it by Raytheon for a manufacturer who was interested in protecting his design (or in selling $3 replacement tubes for $30...) so it might be anyone's guess. Your best shot at this point is to shoot an e-mail to Raytheon (try tech support or customer service) and hope that some old silverback sees it and has the info rolling uselessly around inside his noggin. I have an RCA HB-3, the biggest and most comprehensive tube data book ever produced, and your number isn't in it. Of course, RCA might not have built that particular device due to patents or low demand, so that might not mean anything. I'm one of the best tube detectives on the planet, and I can't find squat on that one.
I agree, what he may have is an experimental tube. It looks like the QF usually means experimental. the 248 is interesting, I'm wondering if that is a date code or an assembly plant.
Raytheon made a variety of tubes in this style for hearing aids.
In guided missiles (Bloodhound) designed in the UK after WWII there were similar tubes in the guidance systems but I can not remember who made the tubes. Ferranti made the quidance systems and I should be able to remember, but 1960 is a long while ago.
A particularly impressive feat was the development of proximity fused shells with about 3 of such valves to make a sort of doppler radar detonator that could survive being fired from an anti-aircraft artillery gun.
Schools sure are not interested in tubes and one reason might be because of the high voltages involved and litigious parents who have a habit of suing schools for killing kids by electrocution during science classes, and besides, tubes are like horse and buggy technology, nice ride, but slow, and well out of date, and there's a
1,001 other more important things to teach kids about.
If you can't find data at such tube data sites like
formatting link
then to find out what's inside any tube you just have to experiment to find out. Not so easy, but the principles of operation of the sub-mini tubes is the same as most others, you need a heater voltage just right, anode to cathode voltage just right, grid and other electrode voltages just right, and see what you get using meters and oscilloscope.
Some sub-minies were used for hearing aid apps, so B+ was not high, nor was filament voltage and current. But principles are the same.
Not many people I know bother trying to use sub-minies for anything because most apps these days use octal, mini 9 pin or 7 pin tubes and plugs and sockets. Some ppl are say the best audio preamp might be made using a sub-mini with soldered in tube leads. I can't argue with them because I've never heard a preamp using sub-minies but I have an order from a guy wanting me to build such an amp. If you search around you'll find quite a few type numbers were made, but only very few have been given special status for hi-fi amps, and those tend to be high gm twin triodes. If you donate the truckload of sub-minies you have to Mr X who says he might like to use them it is most likely they will lurk on Mr X's garage shelf until he dies and never get used, and then be chucked out to the tip within 10 years by his relatives who don't care about the useless junk.
I'd put them on Ebay in lots of 5 pieces. Just start with one lot and see how much money it fetches. If you don't like the money, donate the money to any charity you like.
--
Failure does not prove something is impossible, failure simply
indicates you are not using the right tools...
nico@nctdevpuntnl (punt=.)
--------------------------------------------------------------
Our eBay sales of subminiature Raytheon tubes have been abysmal. The market is zero.
<
formatting link
>
--
Many thanks,
Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email: don@tinaja.com
Please visit my GURU's LAIR web site at http://www.tinaja.com
Thats because your pictures look weird (not like the actual item), the prices are a tad high and you don't ship overseas.
--
Failure does not prove something is impossible, failure simply
indicates you are not using the right tools...
nico@nctdevpuntnl (punt=.)
--------------------------------------------------------------
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.