# DIY semi-con FWR



## Paul Running (Apr 12, 2020)

Don’t throw out that faulty octal base device…you can repurpose it as a SS rectifier unit. Strip the innards out and solder in your favourite diodes; handy for experimenting.


----------



## jb welder (Sep 14, 2010)

What kind of diodes do you use to handle the reverse voltage with single diodes like that?
Used to be we would use three 1N4007 in series for each of those shown.
(edit: that should read 1N4004)


----------



## Paul Running (Apr 12, 2020)

I use the UF4007 for most of my tinkering however, most of my projects and commercial amps are tube rectified, including my V2 which uses dual 5V4s. I will admit that I favour VTT over semi-con technology which no doubt clouds my judgement when selecting components for a project.


----------



## Paul Running (Apr 12, 2020)

9-pin version:


----------



## Paul Running (Apr 12, 2020)

jb welder said:


> handle the reverse voltage with single diodes


Thanks for the heads-up, I don't have them in stock...may I ask you for a recommendation?


----------



## jb welder (Sep 14, 2010)

Paul Running said:


> Thanks for the heads-up, I don't have them in stock...may I ask you for a recommendation?


For 4007 type diodes, just use 2 in series per leg.
I was mistaken where I said we used 3 x 1N4007 per leg, we were actually using 1N4004. So that gave 1200V reverse peak voltage per leg.
Something like a Super, with 375-0-375V power xfmr, you will have a little over 1000V peak reverse per diode if you use single diodes there. Using two 4007 per leg gives you 2000V so a nice safety margin.
If you want to use single diodes, modern Fender for these applications uses BYD33V which are 1200V rating.
SF1600, GP10W or GP10Y would also be good options.


----------



## Paul Running (Apr 12, 2020)

Here's an extract from a GE Hobby magazine, concerning the details for using silicon subs as rectifiers.


----------



## Alan Small (Dec 30, 2019)

nice. thanks for the link


----------

