Converting tube rectifier to solid state rectifier.

[Karl]

Hello

I am overhaulin my first amp. It is a Vibroverb clone and it has a GZ34 rectifier and one of the changes I am going to do is replacing it with a solid state rectifier.

The PT puts out 355-0-355 and with GZ34 it puts out a 465V B+. If I replace it with a solid state one the B+ will be 500V according to my calculations.

What is the best way for me to drop the B+?

I can only think of two ways to to this. One is placing a dropping resistor in between the rectifier output and filter caps to drop the voltage down 35V?
The other is using the 240V primary instead of 230V I am using now. That change would result in a little lower B+ but also change the bias and heater voltage.

Does anyone have a better solution to this problem?

[Cygnus X1]

Why?

The GZ34 is one of the sweetest rectifier sounds there is.

Just my opinion...

[Kregg]

You might check here: http://www.tedweber.com/
Check out the copper cap rectifiers or the V-Dump.

[Structo]

I dropped the B+ on an amp I built by putting a 130v 50w zener diode on the center tap of the HT.

It did not affect my heater voltage.
This was a cathode biased amp.

[M Fowler]

Make sure the zener is the AK type and bolt directly to the chassis as a heat sink.

Mark

[Structo]

Yeah I used the big stud mount 50w zener. I mounted through the chassis near the main ground stud. Used heat sink compound between the diode and chassis.
And it does get hot!

[briane]

other options:

get a sovtek diodes in a tube base thingee (forge what their called)...That just drops in, less than 10 seconds.

Then up the value of the first drop resistor.

[Zippy]

get a sovtek diodes in a tube base thingee (forge what their called)...That just drops in, less than 10 seconds.

Or roll your own - it's easy enough to make 'em.

[Kregg]

Why?

The GZ34 is one of the sweetest rectifier sounds there is.

I'm not sure I follow ... aren't rectifier tubes used to convert ac to dc?

[M Fowler]

Kregg,

He can either use a GZ34 tube rectifier or take an empty tube socket and solder in four diodes to make a solid state rectifier to plug into the tube rectifier spot. More power with SS but the tube gives you sag.

Mark