Most likly the arcs are happening between g1 and cathode or between the beam formimg plates and anode. I would add around 8 neon bulbs too the feedback coil connection with a resistor and fast diode in seried to clamp the negative pulse the tubes already "clamp" the positive pulse but not the negative one
Yes i had more problems with arcing when i had 12 turns for the feedback (now 10) its the g1 i think too. Already tryed it with neon bulbs😃 but only on my small teslacoil.
impressive!!.... about the three windings and their arrangement, it seems approved that the primary must be fairly wide compared to the secondary, like double the diameter or slightly less, then you can make it higher, this has a beneficial effect for both VTTCs and SSTCs but for different reasons probably, a VTTC seems to need some ratio of resonant freq. between prim. and sec., not identical (primary higher), and the more the two coils are coupled the more complicated and unstable it becomes, you put the two coils on different heights instead of making the primary larger (it's probably worse but not by much).... about the feedback coil, IN MY OPINION, it's more important the amount of turns you make rather than its position, better make a bit less of turns, and i'm having satisfactory results with a FB coil on the bottom and wound on a piece of pipe intermediate in size between prim. and sec. ... and obviously the highest part of the outer pipe is better to be primary to improve the coupling VS the risk of arcing... nonetheless your coil is AWESOME!! :D
Wow thanks for that nice informative comment!😊 Yeah somehow i got to the point where it is build different, but also kind of works😅 Yes i reduced the feedback down to 7 turns and it worked better.
Soon i will get my gu81m... i know, like everyone build a VTTC with that, and it feels like a littlebit "mainstream"😂 but with this tube, i want to build a "standard" VTTC and hunting for the longest arcs possible😄
@@marvswelt2587 you should look at the coils "tested to destruction" makes if you want to see good coils made with that tube, but i'm not sure if he still shares some details, also there are a pair of russian videos with that tube with really good results... you find several schematics but those are mostly entry level... i have a GU81M but i did quite little with it
Really cool, I am still trying to get decent arcs myself, sadly yesterday i fried my GU-81M tube by overcurrenting it, the grids melted and shorted part of the filament
@@marvswelt2587 Well we leanred that the maximum current for the gu-81m is 0.7A and thats pushing it past rated grid dissipation already. Datasheet maximum is 0.6A. Please keep an eye on your voltages. I wonder how this tesla coil would work using the hartley oscillator that you can see on my channel. Remmeber that your feedback ratio needs to be very small, half a turn should already work for your tubes
@@janno288 i think i stay with the scheme like it is. I just have to tune it better. The pl36 plate dissipation is around 10w In comparison with the gu81m (400w) the tubes are a joke😄 they are driven completely out of specs. The gu81m can do it too. I think the problem is somewhere different with the gu81m
Hmm good question! At first i love tubes! They ever had something magical to me as a kid. And tubes are cheaper, can be well heavily overdriven, you can actually see when they get too hot and the circuits are fairly simple🙂 Or in short: cheap, simple, more room for error
@@Electronichub_05 dankeschön🙂 Ui ok die röhre kannte ich noch garnicht! Immer schön mal was neues zu finden. Die kann was😃 Ja, ich hab mir jetzt 2 gu81m röhren bestellt, ich denke das "Preis leistungsverhältnis" ist unschlagbar... aber ja billig ist das ganze nicht🫠
@@Electronichub_05haha ne aber die hatte ich auch schon im blick😄 ebay hab ich nicht vertraut.. hab dann nach ewig langer sucherei einen kleinen onlineshop aus süddeutschland gefunden, der noch 2 Stück hatte😊 55€ pro röhre (neu) ist echt ok!
amazing output for those little tubes
@@ElectronHVChannel thanks mate🙂
Most likly the arcs are happening between g1 and cathode or between the beam formimg plates and anode.
I would add around 8 neon bulbs too the feedback coil connection with a resistor and fast diode in seried to clamp the negative pulse the tubes already "clamp" the positive pulse but not the negative one
Yes i had more problems with arcing when i had 12 turns for the feedback (now 10) its the g1 i think too.
Already tryed it with neon bulbs😃 but only on my small teslacoil.
impressive!!.... about the three windings and their arrangement, it seems approved that the primary must be fairly wide compared to the secondary, like double the diameter or slightly less, then you can make it higher, this has a beneficial effect for both VTTCs and SSTCs but for different reasons probably, a VTTC seems to need some ratio of resonant freq. between prim. and sec., not identical (primary higher), and the more the two coils are coupled the more complicated and unstable it becomes, you put the two coils on different heights instead of making the primary larger (it's probably worse but not by much).... about the feedback coil, IN MY OPINION, it's more important the amount of turns you make rather than its position, better make a bit less of turns, and i'm having satisfactory results with a FB coil on the bottom and wound on a piece of pipe intermediate in size between prim. and sec. ... and obviously the highest part of the outer pipe is better to be primary to improve the coupling VS the risk of arcing... nonetheless your coil is AWESOME!! :D
Wow thanks for that nice informative comment!😊
Yeah somehow i got to the point where it is build different, but also kind of works😅
Yes i reduced the feedback down to 7 turns and it worked better.
Soon i will get my gu81m... i know, like everyone build a VTTC with that, and it feels like a littlebit "mainstream"😂 but with this tube, i want to build a "standard" VTTC and hunting for the longest arcs possible😄
@@marvswelt2587 you should look at the coils "tested to destruction" makes if you want to see good coils made with that tube, but i'm not sure if he still shares some details, also there are a pair of russian videos with that tube with really good results... you find several schematics but those are mostly entry level... i have a GU81M but i did quite little with it
Really cool, I am still trying to get decent arcs myself, sadly yesterday i fried my GU-81M tube by overcurrenting it, the grids melted and shorted part of the filament
Oh nooo sorry for your loss🤕
@@marvswelt2587 Well we leanred that the maximum current for the gu-81m is 0.7A and thats pushing it past rated grid dissipation already.
Datasheet maximum is 0.6A.
Please keep an eye on your voltages.
I wonder how this tesla coil would work using the hartley oscillator that you can see on my channel.
Remmeber that your feedback ratio needs to be very small, half a turn should already work for your tubes
@@janno288 i think i stay with the scheme like it is. I just have to tune it better.
The pl36 plate dissipation is around 10w
In comparison with the gu81m (400w) the tubes are a joke😄 they are driven completely out of specs.
The gu81m can do it too.
I think the problem is somewhere different with the gu81m
🇧🇷Tell me: why not use High Voltage Semiconductors instead of Valves❓
Hmm good question! At first i love tubes! They ever had something magical to me as a kid.
And tubes are cheaper, can be well heavily overdriven, you can actually see when they get too hot and the circuits are fairly simple🙂
Or in short: cheap, simple, more room for error
Sehr schön :)
Muss demnächst mal eine weitere basteln mit einer GK-71.
So ein Murks das die Teile immer so teuer sind :(
@@Electronichub_05 dankeschön🙂
Ui ok die röhre kannte ich noch garnicht! Immer schön mal was neues zu finden.
Die kann was😃
Ja, ich hab mir jetzt 2 gu81m röhren bestellt, ich denke das "Preis leistungsverhältnis" ist unschlagbar... aber ja billig ist das ganze nicht🫠
@marvswelt2587 die von ebay wo da ein sockel dabei ist? Die hab ich auch bestellt gehabt und die waren echt am günstigsten 😅
@@Electronichub_05haha ne aber die hatte ich auch schon im blick😄 ebay hab ich nicht vertraut.. hab dann nach ewig langer sucherei einen kleinen onlineshop aus süddeutschland gefunden, der noch 2 Stück hatte😊 55€ pro röhre (neu) ist echt ok!
🇧🇷Tell me: why not use High Voltage Semiconductors instead of Valves❓
@@claytonsulivan because it's not as cool :)