Ultra Rectifier Board

[macula56]

has anyone ever seen this before? would this be a good setup or is it overkill? i recently ordered diodes from Doug and thought about trying this setup. thanks, JMac.

[TIMBO]

Seen it,never used it. It helps tame the hash that you get with SS rectifiers.

[Ed_Chambley]

Saw it in a Bassman I repaired.  Couldn't really tell and difference with it or without it.  No reason not to use it if you want.

[macula56]

cool. i think i will try it and see if it makes any difference. i've got all the resistors and caps already and i just got some heavy duty diodes from Doug. thanks.

[Willabe]

Using ultra fast diodes can help a great deal with the hash. Their turn on/turn off time is much shorter (faster).


               Brad     

[macula56]

where do you get ultra fast diodes from Brad?

[Willabe]

where do you get ultra fast diodes from?

Mouser, Digikey, any of the big catalog/e-mail parts companies.

What you bought from Doug are more than fine as 100's of thousands of amps have been made with them.

Merlin says all you need is 1 UF diode after the regular ones to kill off most to all of the SS hash. So if your making your own rectifier board use what you have and if you want just add a single UF in series with the SS B+ output. That will filter out most of the hash.

You could temp in the UF diode on a switch, that way you could hear it for yourself if it really makes a difference in sound? You just need a stand by type (rated to handle the B+ dcv and current) switch like Fender used (for safety) Doug sells them. 

Some say they can hear it others say they don't. I don't think their magic voodoo parts and they don't carry the big $$ price of said magic voodoo parts. I do think that what's explained about how they work seems to make sense and for almost the same price why not?   

Kevin O'Connor is big on them too. Their very close in price when you buy a 100 or more and they'll last a long time on the shelf.

I brought them up because you titled your thread "ultra rectifier". Dan Torries when he wrote for Vintage Guitar Mag years ago and then wrote a book on tube amps had the same B+ mains rectifier circuit in it. But the UF diodes have come in play and their price has dropped since then.

There's also a snubber circuit that guys use with the UF diodes instead of the circuit you posted. KOC has it in a few of his TUT books and it can be found on line.

I have not set up an A/B test between any of the different version's of  SS B+ power supplies but what I have built with the UF/snuber circuit are very quiet with no hash that I can tell of.   


              Brad     

[macula56]

ultra rectifier is what it is refered to on the site where i found it.  good info Brad, thanks a lot. i have the TUT books. i'll look for it.

[Willabe]

Mac, full UF diodes/snuber circuit explanation can be found in; TUT4, power management chapter, page 10-14, figure 10-26.

I'm pretty sure it's in TUT5 also, but I can't find it right now. 

TUT3 shows the same snuber circuit, but lists it as "Making a SS diode perform like a tube rectifier." But has no mention of UF diodes.


                 Brad           
   

[echuta13]

I use UF4007's in pretty much everything I build.  You could go overkill though and use UF5408's...  The UF4007 cost around $.10 each in packs of 100 from Mouser.

[Willabe]

IMO, the resistors are there to simulate the qualities found in selenium diodes.

No, I think the R's are for forcing voltage/workload sharing so you don't end up with 1 diode doing all/most of the work. If that happens using 3 diodes in series doesn't matter.

I'm not sure that modern diodes need the R's as now a days their ability to make very good quality diodes consistently is so much better now.


            Brad      

[sluckey]

Something else you may consider...

When using modern diodes with a 1000V PIV rating, you only need two diodes in each string, rather than three per string, for all but a handful of amps that use very high B+.