Would like to use E130L in Triode mode with 400-450V on the plate and g2 and -80 to -100V on g1 (should work but I have not tried yet). Should giv at least 25W into a Zpp of 8-10kohm with real good efficience.
Has anybody ever tried a E130L in class B triode connection?
Also other alternatives (like driving both grids or only g2) migth be worth trying as long as the ratings (and I dont mean the published rating for 250V on g2) arent exeded.
Please let me know what you guys think ...
Has anybody ever tried a E130L in class B triode connection?
Also other alternatives (like driving both grids or only g2) migth be worth trying as long as the ratings (and I dont mean the published rating for 250V on g2) arent exeded.
Please let me know what you guys think ...
I take your point that g2 power rating is usually the problem, but exceeding g2 voltage rating can result in sparks. However, help is at hand. Have a look at two current threads:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=96649
http://www.diyaudio.com/forums/showthread.php?s=&threadid=97384
http://www.diyaudio.com/forums/showthread.php?s=&threadid=96649
http://www.diyaudio.com/forums/showthread.php?s=&threadid=97384
hmmm...long thread....interesting reading....
but back to the flashover you mentioned...must open such a bottle and take a look how those grids are spaced...if im lucky then g3 is connected in the socket to the kathode and I can eliminate 1 crucial flasover point, but first I gotta get some more of those tubes...
but back to the flashover you mentioned...must open such a bottle and take a look how those grids are spaced...if im lucky then g3 is connected in the socket to the kathode and I can eliminate 1 crucial flasover point, but first I gotta get some more of those tubes...
This most certainly won't work. E130L is constructed for LOW screen voltages, usually 150 V (which is also marked as recommended voltage for safe operation in its datasheet, the absolute limit being 250 V). Everything above will result in sparking one day.... - I've had some bad experience with that, not on this expensive tube, but with EL36.... screen limit there is 250 V, too, and I tried 280 V - and soon one tube was flashing over. Now, with 225 V, they are running safely.
So 400 V or more on the screen will kill these tubes almost instantly!!!
The only way to get some reasonable power in triode mode out of this tube is operation in "enhanced triode mode" - so using the first grid only for biasing with AC level on cathode or ground, and driving the screen grid with the signal. In that way surely you need a bit a more powerful driver stage.
On the other hand, in conventional triode mode, this should give a good low-voltage tube for OTL and Circlotron designs...... It has quite a powerful cathode.
I'm currrently building such an enhanced-triode-amp with this tube. Should give some neat results. If you are interested, I'll keep you informed. But I beg you some patience, I' don't have much time to work on it at the moment....
So 400 V or more on the screen will kill these tubes almost instantly!!!
The only way to get some reasonable power in triode mode out of this tube is operation in "enhanced triode mode" - so using the first grid only for biasing with AC level on cathode or ground, and driving the screen grid with the signal. In that way surely you need a bit a more powerful driver stage.
On the other hand, in conventional triode mode, this should give a good low-voltage tube for OTL and Circlotron designs...... It has quite a powerful cathode.
I'm currrently building such an enhanced-triode-amp with this tube. Should give some neat results. If you are interested, I'll keep you informed. But I beg you some patience, I' don't have much time to work on it at the moment....
Hi Ulibub
I know E13L is not intended to work the way I am thinking off, but neither is the 6146 wich certainly can be used with a max of
over 900V between g1 and g2.
I think looking at the Datasheet wich only states operation in class A triodemode with 250max is NOT the same than my intended operation in class B. Look at 6146 data, it is also only 250V on g2 in class A triode and say NOTHING about the possibility to run this tube with 400V on g2.
I know E13L is not intended to work the way I am thinking off, but neither is the 6146 wich certainly can be used with a max of
over 900V between g1 and g2.
I think looking at the Datasheet wich only states operation in class A triodemode with 250max is NOT the same than my intended operation in class B. Look at 6146 data, it is also only 250V on g2 in class A triode and say NOTHING about the possibility to run this tube with 400V on g2.
I think the bad thing with using the tube with g1 used to set the gm of the tube and g2 for the drive is that you then just get an other low gm tube and propable need hefty gridcurrent on g2, but I am looking forward on the results of driving this tube only at g2, hopefully they turn out promissing
Salut Corresta!
indeed. Operation mode is completely unimportant for this problem. The only thing that matters is the voltage between g1 and g2, and it is not only the high positive screen potential that accounts for this issue, but also the high negative g1 bias, especially in triode mode. So with - assumed - +400 V on g2 and -100 V on g1, there is a complete voltage of 500 V between these two grids. And so it is ONLY a matter of distance, until field emission will start and arcing over takes place - the more in hot tubes with additional free thermionic electrons available.
but everybody has to make his own experience....
Uli
indeed. Operation mode is completely unimportant for this problem. The only thing that matters is the voltage between g1 and g2, and it is not only the high positive screen potential that accounts for this issue, but also the high negative g1 bias, especially in triode mode. So with - assumed - +400 V on g2 and -100 V on g1, there is a complete voltage of 500 V between these two grids. And so it is ONLY a matter of distance, until field emission will start and arcing over takes place - the more in hot tubes with additional free thermionic electrons available.
but everybody has to make his own experience....
Uli
Yes, Ulibub, exactly my point, it is the voltage between g1 and g2 that counts (and maybe g2 to g3 also). Now, since I dont know how much this tube really can take it is worth a try to find out for real, I hope I can do that in the near future. As for high frequency oscillation, I think that wont be the real problem, offcourse a high gm-tube cant be treated like any old bottle....
or...to be more exact...not the average voltage but the max fieldstrength at the most critically shaped points of the internal construction, emissivity of the used material, temperature a.s.o, I
know all that...only thing I dont know are the practical limits of those tubes because I havnt ever used it, I used some EL3010
but only at low voltages in pentode mood and EL3010 is a bit to expensive to do experiments so I thougth the next best thing is the E130L.....its still comparable cheap ;o)
know all that...only thing I dont know are the practical limits of those tubes because I havnt ever used it, I used some EL3010
but only at low voltages in pentode mood and EL3010 is a bit to expensive to do experiments so I thougth the next best thing is the E130L.....its still comparable cheap ;o)
Yes for sure Gorgon53, 
But as i found most my E130Ls in 75 ohms video line amps, i can say that the mechanical and the wiring should be as short as possible, and not, for example, a single rewiring of a 807 with long wires everywhere. IN fact, the OT should be "reversed" and the G2 should see an OA2 at the foot of the solder . What's an EL3010 ???
But as i found most my E130Ls in 75 ohms video line amps, i can say that the mechanical and the wiring should be as short as possible, and not, for example, a single rewiring of a 807 with long wires everywhere. IN fact, the OT should be "reversed" and the G2 should see an OA2 at the foot of the solder . What's an EL3010 ??? coresta said:... What's an EL3010 ???
a high gm pentode:
http://frank.pocnet.net/sheets/128/e/EL3010.pdf
Andreas
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