3rd order does it
Dunno… I would go with silicon rectification (i.e. "the fastest") and then put it in series with a tunable rate slow-start regulator. You can then have whatever start-rate you like. For your convenience, I've included a 3rd order approximation of a directly heated cathode startup rectification.
All it takes is 3 mid-high value resistors, and 3 smallish electrolytic capacitors. With the documentation in the drawing, it is obvious that this also is LINEAR, meaning that you can use the example's values, multiplied by the effect you're hoping to achieve ratio, and then you have something which react in service as you expect.
Just saying.
GoatGuy
Dunno… I would go with silicon rectification (i.e. "the fastest") and then put it in series with a tunable rate slow-start regulator. You can then have whatever start-rate you like. For your convenience, I've included a 3rd order approximation of a directly heated cathode startup rectification.
All it takes is 3 mid-high value resistors, and 3 smallish electrolytic capacitors. With the documentation in the drawing, it is obvious that this also is LINEAR, meaning that you can use the example's values, multiplied by the effect you're hoping to achieve ratio, and then you have something which react in service as you expect.
Just saying.
GoatGuy
Attachments
Replacing CHOKES with source-followers.
I suppose I should add, that if you place a R4 in series with R3, and in parallel with the associated 3rd order capacitor, you can also create quite a nice 3rd order voltage divider in addition to the 3rd order differential delay.
So… in essence, you can then drive the GATE of a convenient MOSFET at say –20 V (from B+RAW) taking out all those nasty rectification bumps. Moreover, if each of the 3 stages is a “bit of a voltage divider” as well as a long RC time response network, well … then you can drive independent, sequential MOSFET source-followers to suppress ripple to like –120 dB.
In 3 stages.
So,why not? You simply cannot, more cheaply, less problematically get absolutely quiet DC any other way. Even if… you have a closet FULL of “free tubes”. They're magical for this endeavor. I'ven't purchased a high-henry choke in like … 15 years … because of this.
GoatGuy
I suppose I should add, that if you place a R4 in series with R3, and in parallel with the associated 3rd order capacitor, you can also create quite a nice 3rd order voltage divider in addition to the 3rd order differential delay.
So… in essence, you can then drive the GATE of a convenient MOSFET at say –20 V (from B+RAW) taking out all those nasty rectification bumps. Moreover, if each of the 3 stages is a “bit of a voltage divider” as well as a long RC time response network, well … then you can drive independent, sequential MOSFET source-followers to suppress ripple to like –120 dB.
In 3 stages.
So,why not? You simply cannot, more cheaply, less problematically get absolutely quiet DC any other way. Even if… you have a closet FULL of “free tubes”. They're magical for this endeavor. I'ven't purchased a high-henry choke in like … 15 years … because of this.
GoatGuy
You want small...
DM 71, Tube DM71; Rohre DM 71 ID1905, Mag. Stripe, exclamati
The DM71 is not designed as a rectifier diode, but it will act as one, and it will glow very nicely when conducting. Warm up is just a couple of seconds or so, the filament is very low power 25mA at 1.4 V.
Reverse voltage rating - I have no idea. And the cathode current rating is less than 1mA, so probably ruled out on those grounds. I have a handful, so I'll have to try this one day.
DM 71, Tube DM71; Rohre DM 71 ID1905, Mag. Stripe, exclamati
The DM71 is not designed as a rectifier diode, but it will act as one, and it will glow very nicely when conducting. Warm up is just a couple of seconds or so, the filament is very low power 25mA at 1.4 V.
Reverse voltage rating - I have no idea. And the cathode current rating is less than 1mA, so probably ruled out on those grounds. I have a handful, so I'll have to try this one day.
I see you are located in Germany. I bought a lot of them from BTB Elektronik in Fuerth, Germany.
, but at Nuremberg. Only two pcs. left, as of yesterday :-(.In the spirit of display tubes the IV-6 is a cheap 7 segment VFD that offers up to 30mA cathode current with 1.15V and 85mA on the heater. Wire the grid and all the anodes together.
The IV-1 is another indicator tube that could be used. Rated at 5mA anode current and 10mA grid current with the same heater as the IV-6.
The IV-1 is another indicator tube that could be used. Rated at 5mA anode current and 10mA grid current with the same heater as the IV-6.
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