changing diodes with 5AR4 tubes

[trancy]

heloo

I am new in tube PSU design, and I want to change diodes in attached link to schematic with 5AR4 or similar tube. Could someone draw me how to do that...




lp

trens

PSU schematic

 

[Eli Duttman]

Look before you leap. The 1300 VAC CT exceeds the PIV rating of the 5AR4. So, you can't use a 5AR4.
5AR4 Data Sheet

You could use a pair of damper diodes to replace the SS diodes. Be aware that the forward drop in vacuum rectifiers is greater than that of SS. You will also need additional heater power.

Oh yeah, plates are anodes (SS triangles) and cathodes are cathodes (SS bars). The SS diode symbol indicates the direction of conventional current flow.

 

[trancy]

The 1300 VAC CT exceeds the PIV rating of the 5AR4. So, you can't use a 5AR4.

o.k. then some other rectifier tube .... I told that I am new in tube PSU

lp

trens

 

[plovati]

A couple od 3B22.
Same shape of 845, no problem of voltage or current (up to 1A!)

 

[trancy]

yesssssss.....something like that....

question: if voltage goes up thru diode in PSU for 1,41 V, how is with tube "diode"?.....

 

[Hojvaelde]

A couple od 3B22. ][/B

Hmm. My datasheet says PIV is 725 volt for 3B22. To low.

Benny

 

[plovati]

Ach..
so, You need 4 3B22s..
What happen in a tube diode if the PIV is exceeded, arcing? In case of 3B22 it seems difficult, the electrodes are well separated.

5U4 PIV is 1550, one of the highest thru common tubes.

Otherwise... a simple cheap silicon rectifier!

 

[trancy]

so, then 5U4 will be suitable? 2 x ? I can get 5U4.....harder to get 3b22...

lp

trens

 

[Hojvaelde]

Rectifier tube

Hey

Try www.ebay.de. I got 4 pcs 1616 (PIV = 5500) for €30 + freght.


Regards

Benny

 

[plovati]

3B22s are not so hard to find:
http://www.thetubestore.com/cetron3b22.html
it can be uses by a series of diodes and 3B22.

Or, from the same family, 3B25, rectifies up to 1400V dc

http://www.tubedepot.com/nos-3b25.html

Big amplifier, big rectifier!

 

[amperex]

Simple

Use a pair of 6CQ4 6DE4. Operates from 6.3 volts plus slow warmup like a 5AR4.

 

[Hojvaelde]

Hello again

I was thinking.
Is it possible to use EY500 (PY500) rectifier tubes? This tube are easy to get and cheap (used in all old TV set).

The average current is 425 mA (800 mA peak).
PIV = +5kV.

I have never used this valve, so I do not know it is a usable idea.

Regards

Benny

 

[Shoog]

Indeed you should be able to use the PY500,s. They are reputed to be more reliable in the long term.
However you have to face the fact that you will need two of them, and if my memory serves me correctly - they draw considerable heater current - which might mean a seperate heater transformer. I seem to remember that underrunning them might adversely effect their durability.

Shoog