TV Tubes

[stingray_65]

I just aquired a tv repairmans case full of tubes (200+)

There were only a couple 12xx7's and 4 5u4gt's. this thing is loaded with a bunch of different tubes I've never even heard of
I'll post an inventory in the sale/trade later this afternoon
if any one need/ wants any on the inventory list I'll send them out for the cost of shipping.

most are NOS in the box, some are used in the box that I am assuming he put good pulls in. I do not have acesses to a tester to verify any of them.


Ray

[Rob Mercure]

SR,

If you don't get caught up in the trap of what I call "boring common tubes" you might find some jewels that you can design around. Despite all the hoopla from those who wish to sell premium tubes and ascribe philosopher's stone like properties to them one has to realize that audio is just about the least taxing application for a tube and most TV tubes had to work with higher frequencies where tighter tolerances were a must. DC is the "lowest frequency" that tubes operated at with audio being the next lowest. So signal and power application tubes in the video, vertical, and horizontal circuits work well at audio frequencies the only problem being finding circuits designed around them is you don't do design work yourself. And if you don't it's a simple matter to substitute an "other than audio" tube for an audio one and then play with the components/parameters until you get something you like. Fer example the 6GK6 is identical to the 6BQ5/EL84 'cept the basing is different and the supressor grid isn't internally tied to the cathode. And there are scads of other tubes that are identical to audio ones but uncommon in audio. Get a copy of a later RCA Receiving Tube Manual and perhaps Sidley's "Tube Lore" for starters. After all some of the better known HiFi manufacturers such as MacIntosh used HO (horizontal output) tubes in some of there designs as they were cheaper and more rugged than audio designs. Yeah, more rugged as a TV duty is pretty much "continuous duty" while audio applications are a shorter duty cycle.

With all this said and one you'll probably not be able to use the innumerable damper and HV diodes you've gotten although they do make rugged single diode rectifiers nor will you be able to use the 6EK4 type high voltage regulator shunt triodes (although a few hearty souls have!) and there are a few other classes that aren't easy to adapt but the RCA manual will make these clear. But I've never found any of the output tubes - vert, vid, or horrible - to now work well for audio applications and there are probably some audio specific tubes such as 6AQ5s and such in most TV collections.

For the holiday season you can wire a bunch of damper diodes in series until you equal the line voltage for a low-light radiant heater. If you're careful with a propane torch you can heat them until the vacuum pulls the envelope around the elements and if you slowly cool them you can have a really funky tube heater/glow sculpture <grin>. Oh, while some really hate the idea I've had success using the series heater string designed tubes with the "odd" filament voltages in designs that used the heaters in series across the mains to heat them while using a separate B+ only power tranny to provide line isolation. AFter all this is the heater scheme that the tubes were designed for and they have really high heater/cathode breakdown voltages - this allows you to use odd trannies made for SS applications with voltage multipliers to provide B+. Also most less than common heater voltage tubes (6.3 & 12.6) can be used with a series resistor to drop the heater voltage while those higher can have voltage multipliers and/or odd SS trannies provide heater supply (I've got lots of 18-30 VAC SS trannies that power high heater voltage tubes well).

So your use of these valves is only limited by your imagination.

Rob

[Enzo]

But a 1B3 is such a classy looking tube...

[Prairie Dawg]

SR,

If you don't get caught up in the trap of what I call "boring common tubes" you might find some jewels that you can design around. Despite all the hoopla from those who wish to sell premium tubes and ascribe philosopher's stone like properties to them one has to realize that audio is just about the least taxing application for a tube and most TV tubes had to work with higher frequencies where tighter tolerances were a must.

So your use of these valves is only limited by your imagination.

Rob

True...I always wondered why I could hear CB radios on the west coast when I was in Nebraska...it was all those lovely 6JE6 sweep tubes and the bootleg linears people cooked up. It must suck to be an FCC man.

[stingray_65]

!
learnin more every day!

I havent got to inventory them like I thought I would get to do yet, nice weather and family have kept me away.

there has to be a half dozen of those 6AQ5's and 6BG6GT's wich are 6L6's with an anode cap.

I'd like to build a couple odd ball amps. I'm not much into hi output amps, 2 - 10 wattshas a lot to offer if you ask my ears.

I did remove 3 full sets of tubes for AA5 radios. I had to supliment 1 of those with a 50C5 that i had already


well any how I'll still offer what I got here first I'm likely to EBay the rest.

My son said he wanted the caddy, but that was a big reason I paid the entire $10 for the getup and didn't try to dicker with the lady at the garage sale

Ray

[Mark Hammer]

I'm in sort of a similar position, though not quite as plentiful. Clearing stuff out of my late father-in-laws house, my wife found a bag of tubes and set them aside for me. To my delight, there were a bunch of NOS 6GW8s in there, which I am given to understand are essentially the equivalent of an EL84 and a half-12AX7 in one package.

[Prairie Dawg]

!
learnin more every day!

I havent got to inventory them like I thought I would get to do yet, nice weather and family have kept me away.

there has to be a half dozen of those 6AQ5's and 6BG6GT's wich are 6L6's with an anode cap.

I'd like to build a couple odd ball amps. I'm not much into hi output amps, 2 - 10 wattshas a lot to offer if you ask my ears.

I did remove 3 full sets of tubes for AA5 radios. I had to supliment 1 of those with a 50C5 that i had already


well any how I'll still offer what I got here first I'm likely to EBay the rest.

My son said he wanted the caddy, but that was a big reason I paid the entire $10 for the getup and didn't try to dicker with the lady at the garage sale

Ray

I've got a pair of NOS 47s that would make a nice amp...I've even got a schematic somewhere.

[tubeswell]

I'm in sort of a similar position, though not quite as plentiful. Clearing stuff out of my late father-in-laws house, my wife found a bag of tubes and set them aside for me. To my delight, there were a bunch of NOS 6GW8s in there, which I am given to understand are essentially the equivalent of an EL84 and a half-12AX7 in one package.

AFAICT, the ECL86/6GW8 are the most robust of the combined triode/pentode family. They should also make a good reverb driver/recovery in the right location. Check out the driver and output stage in the "low-cost" amp here: ECL86 @ The National Valve Museum

[Rob Mercure]

SR-65

Was thinking about designing with TV and other "orphan" tubes and one thing to do is to see how many of an interesting type you've got and then figure out how long you want the amp to work and set back a "lifetime" supply of tubes. I'm 55 and so at this point of life with many amps if I've got one good set of tubes and another spare I'm probably covered and with a third assured of having a sufficient supply. If you make an amp for sale I'd provide the customer with a "lifetime" supply right off - or make sure to let him/her know that this is necessary just to ensure that your creation will work for a long time. There are many TV "Compactron" tubes which within a 12 pin based envelop packed as many as 4 individual tubes - or more counting diodes. So if you were to design around a compactron you might want to leave enough chassis space so that a future owner could add aditional sockets if they had replace one compactron with 2 9-pin miniatures, for example (compactrons are neat but it's hard to find good chassis mount sockets as TV manufacturers tended to solder the sockets directly to the PCB when the compactrons were popular - sometimes you can get the metal shell of a large 6 or 7 pin tube to fit around a compactron PCB socket). Also if you should design for long life with an orphan tube. While some little bottles like the 6AQ5 like to be run screaming hot - and there are so many of these around that it's not a bad idea - the some desirable compactrons are getting scarce enough that limiting the dissipation and such is a good design practice.

Just some thought that popped into to my head late last night.

Rob

[black_labb]

i made an amp with 2 6bl8's in the preamp/PI. they are a combined pentode and triode. the triode is similar to a 12ay7(maybe 12au7, whichever is the one with gain of 20). there are a number of similar tubes that have the same pin out and are quite similar. i saw a list somewhere, but cant remember where. they were used in the tuning mechanism in a tv.

the amp sounds great imo. i kind of wish i had a separate channel with a 12ax7 or similar just to judge the difference, but i'm very happy with the sound.

[Rob Mercure]

BL

If you get a hold of one of the lat RCA receiving tube manuals you'll find scads of crazy tubes for complex wave generators and such. Triodes with 4 plates or various sorts of electrostatic deflection of signal from one plate to another. I'll probably never have time (unless me health dramatically improves) but someone with some creativity could probably cobble up some fun swept effects and such - I know of at least one experimenter that used an ordinary single triode (6AV6 if I remember correctly) with a coil wrapped around it to achieve an insteresting sort of tremelo where some odd feedback scheme altered the waveform every time it swept the triode - wish I could find that schemo again as it was simple. But even simpler may be taking one of the 4 plate triodes and feed a different filtering circuit from each plate then sweep the plates wither sequentially or semi-randomly. Hell, every other type stage effect has been used so why not see if something catchy might come out of the TV tubes - one may discover a gold mine if the right "name" liked the circuit.

And little amps are so easy to build it's not funny. For those who like 6V6 characteristics but want lower output and quicker breakup try the 6G6. Some hifi mag had a circuit for an OTL amp using line voltage output tubes (50L6, etc.,) with about 20 in push-push parrallel (but this dingo did it without an isolation tranny - something that I strongly disrecommend - but iso's are so easy to cobble up I'm not sure why this guy bothered [I do remember that he was in a 240V line country]).

Just wanted to keep folks thinking - you can copy iconic amps forever - and you can buy "kit" 350 Chevy cars by the walmart full - but it takes some creativity to use interesting tubes or to "blow" a Datsun L-20B - 4 cyl using the smog pump from a road tractor. Remember the "flymo" lawnmowers?" I'd like to find about 6, bolt them together with some sort of controller, and see if I can make an "extension cord" hovercraft. Afterall someone did reach several thousand feet in a lawn chair with a dozen or so weather balloons strapped to it <grin>.

Rob

[black_labb]

thanks rob, i'll have to do some research once i have some spare time.