Useing 1/2 and full wave tube rectifer's in amp design

[ElectronTubesRule]

Ok so I want to use as much old school tube and passive components as I can. It is not a matter of not being able to use solid state devices it is actually the opposite. I could build a solid state amp no problem but I want to really build a rig that is really old school. I know already from reading old post's I need to get Orr's book.So I am trying to learn all things tube related.

The problem I am having is not one of voltage handling rather current handling. What I want is a way to tame 2500 Volts @ .800ma CCS with nothing but tubes, diodes resistors and capacitors. So far the beefiest rectifier tube I can find can only handle 300ma but will handle 6000V. So my question is this can I run a rectifier tube or tube diode in paralleled? Everything in me is saying no not to run them paralleled only in series but since that will not help me and I can not find a solid answer on the internet I figured I would ask here.

I trying to be stubborn and make this work because basically I have not seen anyone else do this. Last time I saw a tube rectifier was in a TV and in tube audio amps.

Oh I am using Russian Tubes GI7BT's and GI30 and GI46 tube types.

I am working on getting my license and currently do not talk on any two way radio's at all. I got my Amateur Radio Merit Badge in Boy Scouts then did nothing with it after that. I built my own transceiver based on a design in old isues of Popular Science/ Popular Mechanics Multi Volume Set hard bound. I used mostly parts from TV's that people tossed tot he curb and parts I got at Radio Shack. This was back when Radio Shack actually stocked a lot of components.

I used to help my Dad repair TV's on the side. So while I am not a communication engineer I am handy with a soldering iron and know just enough to get myself in trouble! LOL I understand high voltages can kill. I have a copy or ARRL handbook from 2008, Electronics for Dummies and an old book from the 1950's on Amateur Radio Circuits. So I am relearning everything I have forgotten over the year's. My son is getting into this too and my Brother in law who is an Engineer but not electronics or communication is also slowly getting turned on to this so I am bringing other into the fold as well.

I have multiple 4 year college degree's so I am able to learn new tricks and do the math needed to do what I want. I lack the experience though and that is why I am hear to pick the brains of guys and gals that have done this a lot!


So thanks for your time and advice. I am a do'er and building things with my hands be it a Kit Plane a Hot Rod, Rifle,Computer or now HF RF Linear Tube Amp the process of collecting the part's then creating something useful from a box of parts is what turns me on and get's me excited so do not bother trying to talk me out of this. I know I can not build a product better then what I could buy but that does not matter to me. I am collecting tubes at the rate that Huge Hefner(sp) collects hot blondes!!! LOL The wife is already trying to figure out how to make space in a closset for all the types that keep ariving via USPS!!!!LOL

 

[Shockwave]

I think you'll find all linear amps are using some method of full wave rectification since it's AC ripple is much easier to filter out at twice the line frequency. The difference with older amps that used a pair of tube rectifiers is the secondary of the transformer. They used a transformer with twice the required voltage and a center tapped secondary. This allowed each of the two rectifiers to independently rectify each side of the secondary in reference to the center tap.

Since the phase is inverted between the two sides of the secondary, the rectifier output is pulsed in the correct polarity at 120 cycles. We basically have two half wave rectifiers that are combined through the 180 degree phase shift from the transformer to form one method of full wave rectification. The practice was used in the early days to limit the heat and space required by four rectifier tubes.

One common rectifier tube for RF amplifiers of this era was the 866 mercury vapor tube. They look really cool when in use with their violet glow coming from the mercury being vaporized within the tube. The bad news is they are quite fragile and expensive today. They do not like to be shorted or overloaded. These tubes can be put in parallel to increase current but they should be matched so that they share an equal load.

 

[Captain Kilowatt]

The 833 is not a rectifier tube. The 866 and 872 are good rectifier's. Personally I would avoid tube rectifiers like the plague. They contain mercury and God help you if you break one while it is hot. Mercury vapour is very deadly. One kid died after using a vacuum cleaner to pick up a few drops from a thermometer he broke. In it's liquid form mercury is MUCH safer. They also have a very high forward voltage drop and will result in very poor dynamic range of the power supply voltage unless you use a low bleeder resistance to help tame the voltage swings but that means heat and power wasted.

Naaaaahhhhh, keep the tubes in the finals or modulators and not in the power supply.

 

[Shockwave]

I agree with Captain. All of the equipment I had with these tubes in it from the T-368 to the Valiant have been changed out to solid state plug in replacement rectifiers. In doing this I noticed an increase in output due to the reduced voltage drop. The durability is also higher as the solid state rectifiers can take more abuse.

 

[Kamikaze]

Look for 575A rectifier tubes and hi-potted fil xfmrs.