First VTTC!
Desmogod, Sat Apr 08 2006, 07:17AMOk, It looks like I have just organised a pair of 811A Vacuum tubes.
I have been lurking on HV sites for years, and although I am building a DRSSTC at the same time, I have always wanted a VTTC, there is just something so nice and almost pure about them.
Now once again, Mr Ward comes to the rescue. http://stevehv.4hv.org/VTTC1.htm
Now does anyone have any hints/tips etc on this? I'm pretty confident with the whole thing, so this is just asking for anything non obvious.
Also steve says that the output could have been improved, how? by how much? and to what detriment on reliability?
Re: First VTTC!
HV Enthusiast, Sat Apr 08 2006, 01:03PM
You could try emailing John Freau (search GOOGLE for his email address). The circuit Steve Ward is using for his dual 811A is John Freau's original circuit, so if you email John, he might have some additional insight to what could be improved etc...
HV Enthusiast, Sat Apr 08 2006, 01:03PM
You could try emailing John Freau (search GOOGLE for his email address). The circuit Steve Ward is using for his dual 811A is John Freau's original circuit, so if you email John, he might have some additional insight to what could be improved etc...
Re: First VTTC!
..., Sat Apr 08 2006, 06:58PM
I should point out my 811a coil just for the heck of it... Running at ~1.5mhz and a .65nf tank cap I could use a single 811a tube at 2kv or a pair at 4kv no interupter (yes, 811a'a can hange much more than 2kv)
Adding a sttataco (interupter) woud increase streamer length...
..., Sat Apr 08 2006, 06:58PM
I should point out my 811a coil just for the heck of it... Running at ~1.5mhz and a .65nf tank cap I could use a single 811a tube at 2kv or a pair at 4kv no interupter (yes, 811a'a can hange much more than 2kv)
Adding a sttataco (interupter) woud increase streamer length...
Re: First VTTC!
Dr. Drone, Sat Apr 08 2006, 07:18PM
Dr. Drone, Sat Apr 08 2006, 07:18PM
Re: First VTTC!
Steve Ward, Sun Apr 09 2006, 02:50AM
VTTCs require much tweaking unless you just follow a design that works already. If its your first VTTC, i would suggest just picking a set of design parameters and sticking with them until it works properly. As to getting longer sparks, you might just want to try a lower tank impedance (that is, larger C and less primary L).
Steve Ward, Sun Apr 09 2006, 02:50AM
VTTCs require much tweaking unless you just follow a design that works already. If its your first VTTC, i would suggest just picking a set of design parameters and sticking with them until it works properly. As to getting longer sparks, you might just want to try a lower tank impedance (that is, larger C and less primary L).
Re: First VTTC!
Desmogod, Sun Apr 09 2006, 03:43AM
This is going to be my "display" coil that sits in the corner of the loungeroom looking pretty.
I'll probably go with the tried and true duall 811a like stated but with a staccatto controller also.
To be honest, spark length isn't really that essential with this coil, but reliability is.
And the fact that is has to be "purdy"
Desmogod, Sun Apr 09 2006, 03:43AM
This is going to be my "display" coil that sits in the corner of the loungeroom looking pretty.
I'll probably go with the tried and true duall 811a like stated but with a staccatto controller also.
To be honest, spark length isn't really that essential with this coil, but reliability is.
And the fact that is has to be "purdy"
Re: First VTTC!
Dr. Drone, Sun Apr 09 2006, 03:55AM
Dr. Drone, Sun Apr 09 2006, 03:55AM
Re: First VTTC!
Desmogod, Sun Apr 09 2006, 03:59AM
"Gee, You got a purdy coil boy!"
lol
chris, you have easily got the nicest and most professional looking coils I have seen.
Outstanding, and feel free to use Purdy, it came from your side of the pond anyway, not mine!
Desmogod, Sun Apr 09 2006, 03:59AM
"Gee, You got a purdy coil boy!"
lol
chris, you have easily got the nicest and most professional looking coils I have seen.
Outstanding, and feel free to use Purdy, it came from your side of the pond anyway, not mine!
Re: First VTTC!
Desmogod, Tue Apr 11 2006, 06:26AM
I have read up on shunts, and see that they are used to either bypass a portion of a circuit in the event of a failure, or to "bleed" off some of the power to be used elsewhere.
Now am I correct in thinking that they are the "shims" near the secondary winding of my MOT?
Do they feed the tiny red winding on the MOT, or are they for something totally different?
I notice that most VTTC's have these removed. How does this affect the MOT (If at all)?
Cheers for any help
Rgds,
Jim
Desmogod, Tue Apr 11 2006, 06:26AM
I have read up on shunts, and see that they are used to either bypass a portion of a circuit in the event of a failure, or to "bleed" off some of the power to be used elsewhere.
Now am I correct in thinking that they are the "shims" near the secondary winding of my MOT?
Do they feed the tiny red winding on the MOT, or are they for something totally different?
I notice that most VTTC's have these removed. How does this affect the MOT (If at all)?
Cheers for any help
Rgds,
Jim
Re: First VTTC!
Bjørn, Tue Apr 11 2006, 08:02AM
You may have been reading about current shunts, the shunts in a transformer are magnetic shunts.
This thread may have some useful information:
http://lists.contesting.com/_amps/2006-03/msg00304.html
Bjørn, Tue Apr 11 2006, 08:02AM
You may have been reading about current shunts, the shunts in a transformer are magnetic shunts.
This thread may have some useful information:
http://lists.contesting.com/_amps/2006-03/msg00304.html
Re: First VTTC!
GimpyJoe, Tue Apr 11 2006, 12:50PM
A nice way to make a filament supply is to knock out the shunts (metal laminations between the primary and secondary) and wind your own filament supply in the extra space. This can make your coil much lighter and more compact. However, you will need to make a way to switch the HV on and off so that you can heat the filaments before running the coil.
GimpyJoe, Tue Apr 11 2006, 12:50PM
A nice way to make a filament supply is to knock out the shunts (metal laminations between the primary and secondary) and wind your own filament supply in the extra space. This can make your coil much lighter and more compact. However, you will need to make a way to switch the HV on and off so that you can heat the filaments before running the coil.
Re: First VTTC!
Self Defenestrate, Tue Apr 11 2006, 01:49PM
And that is why I always have an eye out for sulfur hexaflouride high voltage relays.
Self Defenestrate, Tue Apr 11 2006, 01:49PM
And that is why I always have an eye out for sulfur hexaflouride high voltage relays.
Re: First VTTC!
Dr. Drone, Tue Apr 11 2006, 04:26PM
Dr. Drone, Tue Apr 11 2006, 04:26PM
Re: First VTTC!
Desmogod, Tue Apr 11 2006, 04:40PM
I was wondering about the filament supply, and was thinking of how I could "Warm up the set" before I hit the filaments with thousands of volts of goodness. This gives me an ideal way.
I like the variac idea, but I want a very compact unit in a small hardwood box with just the essentials (including tubes) showing. I want a museum quality piece.
When I actually get it all lashed up and running, I'll ditch the variac and try for a soft start circuit to turn on both the HV and filament circuits after a predetermined time to allow correct warm up.
I'd prefer to stay away from anything that isn't era as well, and I have a few other tubes here, so I'll see what I can knock up. No 555's, no MOSFETs.
Need to find some vintage gauges and switches now as well.
Desmogod, Tue Apr 11 2006, 04:40PM
Funky wrote ...
A nice way to make a filament supply is to knock out the shunts (metal laminations between the primary and secondary) and wind your own filament supply in the extra space. This can make your coil much lighter and more compact. However, you will need to make a way to switch the HV on and off so that you can heat the filaments before running the coil.
A nice way to make a filament supply is to knock out the shunts (metal laminations between the primary and secondary) and wind your own filament supply in the extra space. This can make your coil much lighter and more compact. However, you will need to make a way to switch the HV on and off so that you can heat the filaments before running the coil.
I was wondering about the filament supply, and was thinking of how I could "Warm up the set" before I hit the filaments with thousands of volts of goodness. This gives me an ideal way.
I like the variac idea, but I want a very compact unit in a small hardwood box with just the essentials (including tubes) showing. I want a museum quality piece.
When I actually get it all lashed up and running, I'll ditch the variac and try for a soft start circuit to turn on both the HV and filament circuits after a predetermined time to allow correct warm up.
I'd prefer to stay away from anything that isn't era as well, and I have a few other tubes here, so I'll see what I can knock up. No 555's, no MOSFETs.
Need to find some vintage gauges and switches now as well.
Re: First VTTC!
Vaxian, Wed Apr 11 2007, 08:17AM
All this talk about Purdy coils makes me want to build another one.
I make most of my projects from Lexan, it is as easy to work with as wood and you can see the guts of the coil. The wiring needs to be organized well though to achieve "Purdy".
Here is my VTTC, not so Purdy but it is basically a test bed for the next one, and the next...
Vaxian, Wed Apr 11 2007, 08:17AM
All this talk about Purdy coils makes me want to build another one.
I make most of my projects from Lexan, it is as easy to work with as wood and you can see the guts of the coil. The wiring needs to be organized well though to achieve "Purdy".
Here is my VTTC, not so Purdy but it is basically a test bed for the next one, and the next...
Print this page