900v. 100ma. Power supply for 813 tube amplifier

[Eli Duttman]

Spec sheets look interesting, Eli. Do you know where these diodes can be purchased?

Tube Builder (www.tubebuilder.com) carries the SiC Schottkys.

The 1200 PIV parts are costly, but the 1 A./600 PIV parts are under 2 USD each. You can build a bridge rectifier with UF4007s in the ground legs and SiC Schottkys in the B+ legs that will be very quiet, as the Schottkys block the PN reverse recovery spike. IMO, containing costs while retaining performance can't be bad.

 

[noyan]

SE813 AMPLIFIER SHEMATIC

HERE THE SHEMATIC OF 813 TUBE AMPLIFIER.
http://homepages.ihug.co.nz/~rwillis/alex/

 

[jackinnj]

if you have to regulate

this is a close approximation of the Horowitz and Hill HV regulated supply with a voltage doubler. i have used this supply for a HV lab supply -- instead of a reference I use a DAC, etc., etc.

you might have to adjust the compensation values for your particular situation.

the bottom of C3 should be grounded.

 

[noyan]

power supply

OK. What is Q2 ?

 

[jackinnj]

Re: power supply

OK. What is Q2 ?

Take a look at the parametric search engines at International Rectifier or Fairchild Semiconductor -- Fairchild, in particular, should have out their 1200 Volt Super MOSFET. (They talked about it on one of their web-seminars recently.)

The supply I have built only goes to ~400 volts, I am using IRFPG40's.

 

[georgehifi]

Look at the voltage doubler power suppy at`s used in my 805 SET at Dave (planet10) so kindly posted for me, it works well as is simple.

http://www.diyaudio.com/forums/showthread.php?s=&threadid=33992

Cheers George

 

[noyan]

IXTP3N120 1200V/3A SUPER MOSFET

If i use: IXTP3N120 1200volts / 3A high voltage super mofset in my shematic and remove IRF740 and BUX48. Then, 900 volts will not be a big deal for such strong mosfet. ???

 

[jackinnj]

Re: IXTP3N120 1200V/3A SUPER MOSFET

If i use: IXTP3N120 1200volts / 3A high voltage super mofset in my shematic and remove IRF740 and BUX48. Then, 900 volts will not be a big deal for such strong mosfet. ???

The circuit I have shown would also require that the values of the caps in the doubler be capable of handling more than 450V for 900V out -- thus you would use a pair in series -- i.e. 680uF/350VDC.

The Ixys transistors are available from Digikey (if anyone is wondering) they are $6.09 ea.

 

[benny]

i was just wondering... i had a look at george's power suply, and saw the two diodes in series on it, and it made me think how many times i have seen this used... so maybe i'm getting a little off topic, but what is the advantage of putting two diodes in series? is this to do with the switching noise or something??? anyone on this post know?

cheers

 

[noyan]

serial diodes

I am wondering too.

 

[SY]

You series diodes (with voltage equalizing resistors across them) to form a diode with a higher working voltage. For example, two 1000V diodes in series would form the equivalent of a 2000 volt diode. The only difference between that composite diode and a "genuine" 2000V diode is that the composite will have two times the voltage drop, i.e., 1.4V rather than 0.7V.

 

[fdegrove]

Hi,

two times the voltage drop, i.e., 1.4V rather than 0.7V.

Due to that they are a little better at surviving inrush current surges and yes, the spikes are a little less pronounced than on a single diode too.

In the circuit as shown by George they're used in a voltage doubler so the 1N4004 being a 400V 1A device wouldn't have a chance when left on its own there, hence the 2 diodes in series making it essentially a 800 Fv device at 1A and 800V PIV but with a Fvd of 1.4V iso 0.7V as SY has pointed out.

Cheers,