5R4WGY/A/B , input filter capacitors

[riccardo]

Hello,
i need some information about these valve rectifier.

I would know if it is possible use the 5R4WGB in a capacitor-input filter, with a first cap of 100 uF, or it's dangerous.

If negative, what do you think could be a right value for this cap?

40 uf, could be right?
I'm sorry, but i'm doing a Loftin White 2A3 amp, from the italian review AUDION. The originale project was by Nobu Shishido, but the review Audion set a 5R4WGY in the schematics, and i buyed them. so i'm i trouble now....
Excuse for my english, and thanks
Bye
Riccardo

[anatech]

Hi Riccardo,
I'm seeing values of 4 ~ 20 μF in the data sheets for capacitor input. 100 μF is abusive to the tube in any case, normally 40 ~ 50 μF is the max.

-Chris

[Eli Duttman]

The data sheet says 4 muF. max. I'm a stickler for not violating published limits and would go no higher than 4 muF.

Follow the 1st filter cap. with a low DCR choke and then pile up the energy storage.



5R4 Data Sheet

[Geek]

A trick I do is an input cap of 10uF, then after the L, have a 220uF cap from a computer power supply. No ripple, eh?

[anatech]

Hi Eli,
I found a data sheet that states 20 as a maximum for capacitor input. It depends on the voltage and current draw so .... But not 100 !!!

-Chris

[Marcello1]

Hi Riccardo,

according to datasheet the input cap must be 4 uF, but the thing you had to pay more attention is the plate supply impedence that have to be not less than 2 x 125 ohm if you're using this diode in full wave rectifier, otherwise you'll reduce the tube's life.

Marcello

[riccardo]

Hello, and many thanks!!!
The filter with input cap of 10uF, and then 220 uF it's interesting, i'll try with PSUII.
Chris, i have a 5R4WGB, : could you post the link of datasheet with filter input cap of 20 uF? Could be a better solution.
Marcello, thanks, i'm not so technical, so you said that's it impossible go over 4uF. Or this value it's related with plate impendance? How i can calculate that?
I haven't the datasheet of 5R4WGB...
The ampli input filter is Diode>R50ohm 10 watt> 100uF cap>L10H 150mA>100uF....

Thanks
Riccardo

[Marcello1]

Originally posted by riccardo
Hello, and many thanks!!!
The filter with input cap of 10uF, and then 220 uF it's interesting, i'll try with PSUII.
Chris, i have a 5R4WGB, : could you post the link of datasheet with filter input cap of 20 uF? Could be a better solution.
Marcello, thanks, i'm not so technical, so you said that's it impossible go over 4uF. Or this value it's related with plate impendance? How i can calculate that?
I haven't the datasheet of 5R4WGB...
The ampli input filter is Diode>R50ohm 10 watt> 100uF cap>L10H 150mA>100uF....

Thanks
Riccardo

in my opinion should be: R > diode> 4 uF cap> L10H> 100uF
where R = (250 ohm - transformer DC res. ) and must be 10W or more

The datasheet is attached on eli's reply.

Bye

[kmtang]

I like having higher value input capacitor for the power supply. It sounds better and less hum.

The 5U4G can stand for 47uF input capacitor. I think 5U4G is better the 5R4.


Johnny

[riccardo]

Hi Marcello,
i think what you say is very important.
i'm sorry for my english, but i try to explain:
It is'nt equal if the plate "see":
Transfomer impedance> Diode> R (250 ohm - TA impendance) 4uF etc?

You see, in the original Nobu Shishido Loftin White 2A3 project, http://www.audiodesignguide.com/se/l...white_2a3a.jpg
he use a rectifier 5AR4 ( From Datasheet : filter input capacitor max 40 uF) but the input filter is:
5AR4> R50 ohm 10 W >100uF > L 10H 150 mA>100uF....
So i think that could be a solution for calculate a greater input filter cap for 5R4WGB.
And i don't immagine HOW.....
Thanks
Ciao
RR
(
(quote)
in my opinion should be: R > diode> 4 uF cap> L10H> 100uF
where R = (250 ohm - transformer DC res. ) and must be 10W or more

The datasheet is attached on eli's reply.

Bye