converting to solid state rectifier

[Regis]

I pinged Old Tele Man (Earles) a while back about this, here is his reply and a pic. You can get sockets from Doug Hoffman or I suppose you could bust up an old tube. I thought I had info on adding resistors for sag but can't find it. It might have been in one of KOC's books.

1) solder anode-end of one 1N5408 diode (or equivalent) to pin 4 of octal socket.
2) solder anode-end of other 1N5408 diode to pin 6 of octal socket.
3) solder the two cathode-ends of of the 1N5408 diodes together into pin 8 of octal socket.

The 1N5408 is a hefty high-voltage diode; but, you could use cheaper 1N4000-series diodes, but will have to "stack" three of them in series to handle the high voltage, just to be safe.

[Steve A.]

Another alternative is a simple switch to go between a solid state and a tube rectifier:

http://www.blueguitar.org/new/schem/...ct_ss-tube.gif

And yes it does throw the bias off a little so you look for a setting that will work with both positions of the switch.

Steve Ahola

[JoeM]

I've used the base of tube that died for this too, but you can get the SS module type.

Weber has a Copper Cap version with just the diodes.

http://www.webervst.com/ccap.html

(Scroll down the page for the WS1)

[pontiacpete]

Joe, what did you use for a cover when you converted the dead tube to a SS rectifier?
I finally ended up using 3 diodes(IN4007) in series on both of the secondary lines.
To protect the diodes I put .0022uf caps and 1 meg resistors in parallel on each. Then I added in the hum pot that the bassman 20 has in the schematic and no more AC hum.

Thanks to everyone for the links and the help!

[JoeM]

Joe, what did you use for a cover when you converted the dead tube to a SS rectifier?
I finally ended up using 3 diodes(IN4007) in series on both of the secondary lines.
To protect the diodes I put .0022uf caps and 1 meg resistors in parallel on each. Then I added in the hum pot that the bassman 20 has in the schematic and no more AC hum.

Thanks to everyone for the links and the help!

I cut a piece of perfboard and used epoxy to attach it.

[bluemonk]

QUOTED:
1) solder anode-end of one 1N5408 diode (or equivalent) to pin 4 of octal socket.
2) solder anode-end of other 1N5408 diode to pin 6 of octal socket.
3) solder the two cathode-ends of of the 1N5408 diodes together into pin 8 of octal socket.
The 1N5408 is a hefty high-voltage diode; but, you could use cheaper 1N4000-series diodes, but will have to "stack" three of them in series to handle the high voltage, just to be safe.
END QUOTED

it seems that 1N5408 are not higher voltage than 1N4007 but have higher current handling (3A).
Is it safe to use just one 1N5408? Or should they be stacked just like 1N4007?
Thanks

[Albert Kreuzer]

The diodes should be able to take at least double the plate voltage. As long as B+ is less than 500V, one 1N4007 per side should be sufficient. Two is better, three is plenty.

Cheers,
Albert

[socalscott]

Weber has the plug-in mentioned, but it may mimic a tube.

Any reason you didn't use the advice to stiffen things up with a cap?

[pontiacpete]

this amp, a clone of a fender bassman 20, was designed with a solid state rectifier. I thought I would try a tube rectified and there was too much sag and not enough volume for a bass so I converted back to a silicone diode rectifier. I think I used 6 diodes all together, if I'm remembering correctly, and I backed those up w/ caps and resistors in parallel. I think that amp will be coming back to me, because of an intermittent problem, cutting out, I'll be able to look at what I did.