I found a box of 50 of them for near nothing and they have not been opened. I've never heard of them used in audio tube gear.
What do you guys think?
What do you guys think?
I see them used in radios where the screen, which is not attached internally, is used for the oscillator. A mixing tube. Not sure if they are all that good for anything wired as a pentode; maybe headphone amp? They have high filament current.
Dual control pentode used in early computers.
Also used as Blaxshep says in radio transmitters not really for use in serious hi-fi.
Also used as Blaxshep says in radio transmitters not really for use in serious hi-fi.
It's interesting that the data sheet shows they were seeing it used as pentode, tetrode, or triode. What does that mean? I don't know, Jack of all trades not terribly good at any one? or what?
The most promising thing I see in a quick myopic look is that they're good for a bit of current. It gives some room to play.
Did you already pick up the case? If so I would take the time to make some triode curves.
The most promising thing I see in a quick myopic look is that they're good for a bit of current. It gives some room to play.
Did you already pick up the case? If so I would take the time to make some triode curves.
I said screen but it's really the suppressor grid that is not attached, so that being the case I an see how it could be wired as triode, tetrode or pentode as well as a dual control grid mixer. The tube has a lot of possibilities but an amp is not one of them. The high current would make them good power regulator tubes.
No, I didn't want to buy them if I couldn't use them. I was thinking about an OTL amplifier with so many.
Looks similar to 7AK7, there was a thread on this at Can the 7AK7 computer tube work as audio output tube ?
Well spotted Sorento the 7AK7 is the same tube but an earlier version with a different base --B8B base (Loctal )---still not ideal in audio hi-fi.
Nearly any tube can be used for "serious hifi" when some conditions are true.
This makes for a nice, low power pentode. Its long lifetime, low failure rate.
The curves look nice, too.
The asians use so many tubes with great success, that weren't intended for "serious hifi", specially the computer tubes are interesting.
Build a simple circuit, listen and you'll know. No forum can give you own experiences. If I would have heard of the thousand pro/cons in any forum, my amps would have never served. And they serve my quite well.
Nearly any tube/valve can be made to do what you want or prove any theory --that's not my point .
In days gone by tube/valve manufacturers specially made audio tubes--that's right audio tubes but if you spend too much time on websites where "tube rolling" takes place they will try to talk you into believing VM tubes are "great " for audio .
Look you can fit a powerful engine into a mini van but just think of all the modifications you need to do to keep it stable-braking ability - uprated suspension etc etc and that costs at least in time and effort .
And by the way why do so many people think virtual circuits are perfect ?
Time and time again not just here you see the same persons say--well it worked in virtuality but I need help as such and such doesn't work right.
Just read the pages of EW even professional engineers have problems with their "perfect designs " --so "modifications " have to take place in real life .
In days gone by tube/valve manufacturers specially made audio tubes--that's right audio tubes but if you spend too much time on websites where "tube rolling" takes place they will try to talk you into believing VM tubes are "great " for audio .
Look you can fit a powerful engine into a mini van but just think of all the modifications you need to do to keep it stable-braking ability - uprated suspension etc etc and that costs at least in time and effort .
And by the way why do so many people think virtual circuits are perfect ?
Time and time again not just here you see the same persons say--well it worked in virtuality but I need help as such and such doesn't work right.
Just read the pages of EW even professional engineers have problems with their "perfect designs " --so "modifications " have to take place in real life .
You could run the 6888 in ultralinear mode. This would result in lower THD but also with some reduction in gain. I explored running a 6888 in this mode for an AM transmitter.
Antique Radio Forums • View topic - Ultralinear 6888 AM Transmitter
Antique Radio Forums • View topic - Ultralinear 6888 AM Transmitter
Baring in mind the significance of the number 8 in Asian culture, an amplifier with a quad of these tubes would be the luckiest device ever!
The asians love a tube called 6350, a computer triode.
Myself I'm listening very satisfied with Deutsche Post tubes, not intended for audio but for telephone lines (although Klangfilm used those tubes, too).
Its not that kind of simple to sort those tubes out because their intention in the design wasn't audio at first.
I have heard gear with TV tubes, some were implemented to work in very fine sounding phono circuits like EF184 and E83F, D3A and some more.
Thats why I wrote, give it a try, maybe it works. I didn't wrote " simulate the circuit and see how it will sound" because I know, thats not the way it will work out.
In audio, its all about the best implementation of parts and those people, who are not able to implement a tube often say it couldn't be done, but in fact, it just couldn't be done by themselfes, maybe others have better ideas or more knowledge to do it the right way.
Myself I'm listening very satisfied with Deutsche Post tubes, not intended for audio but for telephone lines (although Klangfilm used those tubes, too).
Its not that kind of simple to sort those tubes out because their intention in the design wasn't audio at first.
I have heard gear with TV tubes, some were implemented to work in very fine sounding phono circuits like EF184 and E83F, D3A and some more.
Thats why I wrote, give it a try, maybe it works. I didn't wrote " simulate the circuit and see how it will sound" because I know, thats not the way it will work out.
In audio, its all about the best implementation of parts and those people, who are not able to implement a tube often say it couldn't be done, but in fact, it just couldn't be done by themselfes, maybe others have better ideas or more knowledge to do it the right way.
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There are linear valves and valves that get misused in audio circuits at the wrong place. The 6211 switching tube is a notorious case, not able to linearly put out more than 10V, hyped for having the same guts as ECC802S. Folk working without measurement equipment love its openness (from H3) while dismissing the often times better ECC82 for having "too much distortion".
This is what I was getting at Painted but it doesn't seem to sink in .
Never mind your right I have the Mullard industrial manual and it specifically refers to the ECC82 as specially designed for audio use and gives a long list of operating conditions including Ra anode (plate ) resistors/Rk cathode resistors/Rg grid resistors -- different voltages and distortion values .
The Tube Museum promotes the ECC802S which is probably where all the hype is coming from .
The 802S is a special quality tube designed for military and industrial use not specifically for audio use .
Whats missing is a large range of voltages and operating conditions to give a real perspective of its use in audio .
I suspect its limited to certain operating conditions to achieve optimization.
Never mind your right I have the Mullard industrial manual and it specifically refers to the ECC82 as specially designed for audio use and gives a long list of operating conditions including Ra anode (plate ) resistors/Rk cathode resistors/Rg grid resistors -- different voltages and distortion values .
The Tube Museum promotes the ECC802S which is probably where all the hype is coming from .
The 802S is a special quality tube designed for military and industrial use not specifically for audio use .
Whats missing is a large range of voltages and operating conditions to give a real perspective of its use in audio .
I suspect its limited to certain operating conditions to achieve optimization.
The triode curves linked to in post #10 look OK, but not spectacular like a DHT. Grid 2 is only rated at 150V max on the datasheet, which is kinda low for triode use. (probably can run it up to 250V peak in triode mode) Triode Mu looks around 8.
The given pentode curves look horrible, but like 7AK7, you can put around +12V on grid 3 to square the knees up. The plate to grid 3 capacitance will be higher than a similar pentode, by an extra 50%, due to the finer grid 3 mesh. Not really a show stopper for audio, but it needs to be checked into when designing for pentode like gain. The +12V on grid 3 will keep grid 2 current lower, so you might be able to up rate the tube's plate Watts by a Watt or two.
The max DC current rating of 80 mA does not look promising for OTL.
The given pentode curves look horrible, but like 7AK7, you can put around +12V on grid 3 to square the knees up. The plate to grid 3 capacitance will be higher than a similar pentode, by an extra 50%, due to the finer grid 3 mesh. Not really a show stopper for audio, but it needs to be checked into when designing for pentode like gain. The +12V on grid 3 will keep grid 2 current lower, so you might be able to up rate the tube's plate Watts by a Watt or two.
The max DC current rating of 80 mA does not look promising for OTL.