Author Topic: 833A Cathode Modulation  (Read 3296 times)

Offline Twospoons

  • High Voltage Technician
  • ***
  • Posts: 117
  • Karma: +2/-0
    • View Profile
Re: 833A Cathode Modulation
« Reply #20 on: February 09, 2021, 09:18:09 PM »
BTW, I didn't check the input polarity of the opamps carefully - you'll need to check that the grid bias moves the right way to compensate for cathode current changes.  And as mentioned before, you may need to band limit the feedback around the opamps.

Oh, and that lower opamp wasn't meant to operate as a comparator - I was just too lazy to draw in the feedback resistors to control the gain.

Offline Vdekje

  • High Voltage Enthusiast
  • *
  • Posts: 15
  • Karma: +0/-0
    • View Profile
Re: 833A Cathode Modulation
« Reply #21 on: May 14, 2021, 08:58:15 PM »
Any updates on this? Two of us in a discord are looking into ramping VTTCs as well.

I'm planning on ramping the screen, as done by Lukáš Koval here
I'm using a 8890, and I have a 20kv 48µF bus cap. Since the anode idle current is relatively high without screen voltage (140mA avg with half wave doubled 4.2kv, so much higher with, say, 10-15kv smoothed DC), I'd like to cathode modulate to only have the anode on during the screen ramp.

The other person is trying to get a ramp by sawtooth modulated PWM cathode modulation. He's doing it on a mini-vttc, PL500.

Offline pc50kd

  • High Voltage Enthusiast
  • *
  • Posts: 2
  • Karma: +0/-0
    • View Profile
Re: 833A Cathode Modulation
« Reply #22 on: May 16, 2021, 12:21:23 PM »
Interesting topic. I also played around with a cathode modulated VTTC a while ago.

I used a GU81M vacuum tube and interrupted the cathode with a IGBT.
For modulation I used a audio modulated PWM signal at 0.33 times the resonant frequency of the VTTC driving the IGBT.

I also made a post about it on the 4HV forum. https://4hv.org/e107_plugins/forum/forum_viewtopic.php?p=1&id=29247#post-29348
Unfortunately the schematic posted there is unreadable. But if there is interest I could dive into my archives and see if I can recover it.

« Last Edit: May 16, 2021, 12:23:45 PM by pc50kd »

Offline SalinsLV

  • High Voltage Enthusiast
  • *
  • Posts: 31
  • Karma: +2/-0
  • Electronics experience starting from 2015.
    • View Profile
Re: 833A Cathode Modulation
« Reply #23 on: May 21, 2021, 07:28:55 PM »
I have also built VTTC that plays music. Video of the coil in action:
/>
« Last Edit: October 18, 2021, 12:10:26 PM by SalinsLV »
K. Salins

High Voltage Forum

Re: 833A Cathode Modulation
« Reply #23 on: May 21, 2021, 07:28:55 PM »

 


* Recent Topics and Posts

post Re: Hi! 811 A tesa coil
[Vacuum Tube Tesla Coils (VTTC)]
jpvvv123
Today at 04:13:06 AM
post Re: Self Starting Coil (Not)
[Solid State Tesla Coils (SSTC)]
davekni
Today at 03:34:15 AM
post Self Starting Coil (Not)
[Solid State Tesla Coils (SSTC)]
alan sailer
January 23, 2022, 10:45:46 PM
post Re: GDT Slow Rise/Fall times even with resistor shorted
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
January 23, 2022, 09:06:49 PM
post GDT Slow Rise/Fall times even with resistor shorted
[Dual Resonant Solid State Tesla coils (DRSSTC)]
SalinsLV
January 23, 2022, 07:18:56 PM
post Re: Hi! 811 A tesa coil
[Vacuum Tube Tesla Coils (VTTC)]
304er
January 23, 2022, 06:18:13 PM
post Re: 120VAC Mains Ramped Builds
[Solid State Tesla Coils (SSTC)]
Magneticitist
January 22, 2022, 11:20:55 AM
post Re: 120VAC Mains Ramped Builds
[Solid State Tesla Coils (SSTC)]
ZakW
January 22, 2022, 07:07:09 AM
post Re: GDT Testing
[Solid State Tesla Coils (SSTC)]
johnf
January 22, 2022, 05:27:37 AM
post Re: Help on my "first" SSTC (LabCoatz SSTC 2.0)- Popping transistors
[Solid State Tesla Coils (SSTC)]
davekni
January 22, 2022, 04:27:38 AM
post Re: Hi! 811 A tesa coil
[Vacuum Tube Tesla Coils (VTTC)]
jpvvv123
January 22, 2022, 12:53:04 AM
post Re: 120VAC Mains Ramped Builds
[Solid State Tesla Coils (SSTC)]
Magneticitist
January 21, 2022, 07:36:07 PM
post Re: Muon Decay
[Detection, Counting and Measurements]
Uspring
January 21, 2022, 07:27:23 PM
post Re: Etching PCBs with a SLA 3d printer
[Printed Circuit Board]
TMaxElectronics
January 21, 2022, 02:05:52 PM
post Re: 120VAC Mains Ramped Builds
[Solid State Tesla Coils (SSTC)]
ZakW
January 21, 2022, 09:08:18 AM
post Re: Muon Decay
[Detection, Counting and Measurements]
Da_Stier
January 21, 2022, 08:42:54 AM
post 120VAC Mains Ramped Builds
[Solid State Tesla Coils (SSTC)]
Magneticitist
January 21, 2022, 03:00:04 AM
post Re: Muon Decay
[Detection, Counting and Measurements]
alan sailer
January 21, 2022, 02:16:57 AM
post Re: Help on my "first" SSTC (LabCoatz SSTC 2.0)- Popping transistors
[Solid State Tesla Coils (SSTC)]
TiagoBS
January 20, 2022, 06:56:35 PM
post Re: Muon Decay
[Detection, Counting and Measurements]
Da_Stier
January 20, 2022, 05:19:26 PM
post Re: Muon Decay
[Detection, Counting and Measurements]
alan sailer
January 20, 2022, 03:53:54 PM
post Re: Muon Decay
[Detection, Counting and Measurements]
Uspring
January 20, 2022, 01:20:19 PM
post Re: Muon Decay
[Detection, Counting and Measurements]
Da_Stier
January 20, 2022, 10:11:21 AM
post Re: Muon Decay
[Detection, Counting and Measurements]
alan sailer
January 19, 2022, 08:22:49 PM
post Re: Muon Decay
[Detection, Counting and Measurements]
Mads Barnkob
January 19, 2022, 06:49:36 PM
post Re: Etching PCBs with a SLA 3d printer
[Printed Circuit Board]
hardboiled99
January 19, 2022, 07:37:27 AM
post Primary Coil Winding Technique
[Solid State Tesla Coils (SSTC)]
alan sailer
January 18, 2022, 10:34:48 PM
post Re: Muon Decay
[Detection, Counting and Measurements]
alan sailer
January 18, 2022, 08:46:53 PM
post Re: Muon Decay
[Detection, Counting and Measurements]
Mads Barnkob
January 18, 2022, 08:08:53 PM
post Re: GDT Testing
[Solid State Tesla Coils (SSTC)]
ZakW
January 18, 2022, 07:15:22 PM
post Muon Decay
[Detection, Counting and Measurements]
alan sailer
January 18, 2022, 06:49:48 PM
post Re: Strange reading for grid feedback coil voltage
[Vacuum Tube Tesla Coils (VTTC)]
304er
January 18, 2022, 08:47:53 AM
post Re: QO-100 / EShail 2 Uplink amplifier development adventures
[Radio Frequency]
Da_Stier
January 17, 2022, 09:13:32 PM
post Re: QO-100 / EShail 2 Uplink amplifier development adventures
[Radio Frequency]
Da_Stier
January 17, 2022, 09:05:56 PM
post Re: Help on my "first" SSTC (LabCoatz SSTC 2.0)- Popping transistors
[Solid State Tesla Coils (SSTC)]
Mads Barnkob
January 17, 2022, 07:45:48 PM
post Re: General Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
January 17, 2022, 07:41:34 PM
post Re: Strange reading for grid feedback coil voltage
[Vacuum Tube Tesla Coils (VTTC)]
Mads Barnkob
January 17, 2022, 07:38:25 PM
post Re: SSTC with push-pull configuration
[Solid State Tesla Coils (SSTC)]
Mads Barnkob
January 17, 2022, 07:31:03 PM
post Re: GDT Testing
[Solid State Tesla Coils (SSTC)]
Mads Barnkob
January 17, 2022, 07:28:02 PM
post Re: Induction heater Driver for Flyback?
[Voltage Multipliers]
MRMILSTAR
January 16, 2022, 09:00:02 PM
post Induction heater Driver for Flyback?
[Voltage Multipliers]
abstruse1
January 16, 2022, 07:35:26 PM
post Re: SSTC with push-pull configuration
[Solid State Tesla Coils (SSTC)]
Bambinz
January 16, 2022, 12:21:40 PM
post Re: SSTC with push-pull configuration
[Solid State Tesla Coils (SSTC)]
davekni
January 15, 2022, 07:10:03 PM
post Re: SSTC with push-pull configuration
[Solid State Tesla Coils (SSTC)]
Bambinz
January 15, 2022, 06:31:33 PM
post Re: SSTC with push-pull configuration
[Solid State Tesla Coils (SSTC)]
Magneticitist
January 14, 2022, 08:47:43 PM
post Re: SSTC with push-pull configuration
[Solid State Tesla Coils (SSTC)]
davekni
January 14, 2022, 08:39:07 PM
post Re: Unusual Youtube channel activity
[General Chat]
davekni
January 14, 2022, 08:14:17 PM
post Re: Unusual Youtube channel activity
[General Chat]
Mads Barnkob
January 14, 2022, 08:12:13 PM
post Unusual Youtube channel activity
[General Chat]
MRMILSTAR
January 14, 2022, 05:51:52 PM
post Re: Strange reading for grid feedback coil voltage
[Vacuum Tube Tesla Coils (VTTC)]
304er
January 14, 2022, 08:51:57 AM
post Re: SSTC with push-pull configuration
[Solid State Tesla Coils (SSTC)]
Bambinz
January 13, 2022, 08:20:02 PM
post Re: Help with SSTC feedback circuits with 4046 IC and Schmitt Triggers
[Solid State Tesla Coils (SSTC)]
davekni
January 13, 2022, 05:27:40 AM
post Re: General Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
thedoc298
January 13, 2022, 03:10:32 AM
post Re: Strange reading for grid feedback coil voltage
[Vacuum Tube Tesla Coils (VTTC)]
304er
January 12, 2022, 06:18:15 PM
post Re: Single mosfet bifiliar gdt
[Solid State Tesla Coils (SSTC)]
alan sailer
January 12, 2022, 05:45:26 PM
post Re: Strange reading for grid feedback coil voltage
[Vacuum Tube Tesla Coils (VTTC)]
MRMILSTAR
January 12, 2022, 03:29:04 PM
post Re: Help with SSTC feedback circuits with 4046 IC and Schmitt Triggers
[Solid State Tesla Coils (SSTC)]
AFreshLad
January 12, 2022, 01:30:38 PM
post Re: Strange reading for grid feedback coil voltage
[Vacuum Tube Tesla Coils (VTTC)]
304er
January 12, 2022, 09:09:13 AM
post Re: Strange reading for grid feedback coil voltage
[Vacuum Tube Tesla Coils (VTTC)]
MRMILSTAR
January 11, 2022, 08:05:27 PM
post Re: Nokia Siemens 3G Flexi 2100MHz 50W Amplifier Teardown
[Radio Frequency]
Mads Barnkob
January 11, 2022, 07:42:12 PM
post Re: Strange reading for grid feedback coil voltage
[Vacuum Tube Tesla Coils (VTTC)]
Duane B
January 11, 2022, 07:33:15 PM
post Re: 8x MOT transformer, weird power draw
[Transformer (Iron Core)]
AstRii
January 11, 2022, 06:19:49 PM
post Re: Strange reading for grid feedback coil voltage
[Vacuum Tube Tesla Coils (VTTC)]
304er
January 11, 2022, 05:19:46 PM
post Re: Strange reading for grid feedback coil voltage
[Vacuum Tube Tesla Coils (VTTC)]
MRMILSTAR
January 11, 2022, 04:31:28 PM
post Re: 8x MOT transformer, weird power draw
[Transformer (Iron Core)]
AstRii
January 11, 2022, 03:21:37 PM
post Re: GDT Testing
[Solid State Tesla Coils (SSTC)]
davekni
January 11, 2022, 06:50:49 AM
post Re: Strange reading for grid feedback coil voltage
[Vacuum Tube Tesla Coils (VTTC)]
Duane B
January 11, 2022, 06:34:20 AM
post Re: Help on my "first" SSTC (LabCoatz SSTC 2.0)- Popping transistors
[Solid State Tesla Coils (SSTC)]
davekni
January 11, 2022, 06:24:13 AM
post Re: Strange reading for grid feedback coil voltage
[Vacuum Tube Tesla Coils (VTTC)]
davekni
January 11, 2022, 06:15:08 AM
post Re: Strange reading for grid feedback coil voltage
[Vacuum Tube Tesla Coils (VTTC)]
MRMILSTAR
January 11, 2022, 05:25:31 AM
post Re: Strange reading for grid feedback coil voltage
[Vacuum Tube Tesla Coils (VTTC)]
Duane B
January 11, 2022, 12:07:22 AM
post Strange reading for grid feedback coil voltage
[Vacuum Tube Tesla Coils (VTTC)]
MRMILSTAR
January 10, 2022, 10:56:48 PM
post Re: Hi! 811 A tesa coil
[Vacuum Tube Tesla Coils (VTTC)]
Duane B
January 10, 2022, 09:38:53 PM
post Re: Help on my "first" SSTC (LabCoatz SSTC 2.0)- Popping transistors
[Solid State Tesla Coils (SSTC)]
ZakW
January 10, 2022, 07:50:13 PM
post Re: GDT Testing
[Solid State Tesla Coils (SSTC)]
ZakW
January 10, 2022, 07:19:17 PM
post Re: Help on my "first" SSTC (LabCoatz SSTC 2.0)- Popping transistors
[Solid State Tesla Coils (SSTC)]
TiagoBS
January 10, 2022, 03:13:08 PM
post Re: GDT Testing
[Solid State Tesla Coils (SSTC)]
davekni
January 10, 2022, 04:21:46 AM
post Re: Hi! 811 A tesa coil
[Vacuum Tube Tesla Coils (VTTC)]
304er
January 10, 2022, 03:59:09 AM
post Re: 8x MOT transformer, weird power draw
[Transformer (Iron Core)]
davekni
January 10, 2022, 03:54:59 AM
post Re: GDT Testing
[Solid State Tesla Coils (SSTC)]
ZakW
January 09, 2022, 11:45:09 PM
post Re: Hi! 811 A tesa coil
[Vacuum Tube Tesla Coils (VTTC)]
jpvvv123
January 09, 2022, 11:04:25 PM
post 8x MOT transformer, weird power draw
[Transformer (Iron Core)]
AstRii
January 09, 2022, 04:22:11 PM
post Re: Hi! 811 A tesa coil
[Vacuum Tube Tesla Coils (VTTC)]
Duane B
January 09, 2022, 05:52:11 AM
post Re: GDT Testing
[Solid State Tesla Coils (SSTC)]
davekni
January 09, 2022, 05:10:50 AM
post Re: Performance issues regarding phase angle in SSTCs
[Solid State Tesla Coils (SSTC)]
davekni
January 09, 2022, 01:20:40 AM
post GDT Testing
[Solid State Tesla Coils (SSTC)]
ZakW
January 09, 2022, 12:38:28 AM
post Re: General Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
flyingperson23
January 08, 2022, 06:36:28 PM
post Performance issues regarding phase angle in SSTCs
[Solid State Tesla Coils (SSTC)]
Max Seiringer
January 08, 2022, 03:21:31 PM
post Re: Hi! 811 A tesa coil
[Vacuum Tube Tesla Coils (VTTC)]
304er
January 08, 2022, 09:05:41 AM
post Re: Hi! 811 A tesa coil
[Vacuum Tube Tesla Coils (VTTC)]
jpvvv123
January 07, 2022, 10:20:10 PM
post Re: Hi! 811 A tesa coil
[Vacuum Tube Tesla Coils (VTTC)]
304er
January 07, 2022, 05:56:28 PM
post Re: First SSTC based on profdc9 PCB Pack
[Solid State Tesla Coils (SSTC)]
davekni
January 07, 2022, 05:15:38 AM
post Re: DRSSTC tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
January 07, 2022, 05:01:21 AM
post Re: How to prevent secondary to secondary to primary arcs?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
January 07, 2022, 04:59:59 AM
post Tophat QCW 1
[Dual Resonant Solid State Tesla coils (DRSSTC)]
dbach
January 07, 2022, 02:27:35 AM
post How to prevent secondary to secondary to primary arcs?
[Dual Resonant Solid State Tesla coils (DRSSTC)]
dbach
January 07, 2022, 02:19:40 AM
post Re: General Questions
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
January 06, 2022, 09:33:06 PM
post Re: First SSTC based on profdc9 PCB Pack
[Solid State Tesla Coils (SSTC)]
alan sailer
January 06, 2022, 06:09:39 PM
post Re: DRSSTC tuning
[Dual Resonant Solid State Tesla coils (DRSSTC)]
kubajed
January 06, 2022, 04:48:22 PM
post Re: First SSTC based on profdc9 PCB Pack
[Solid State Tesla Coils (SSTC)]
SK1701
January 06, 2022, 03:05:55 PM

Sitemap 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 
SimplePortal 2.3.6 © 2008-2014, SimplePortal