Tube rectifier & regulator (modified)

[ANALOG GUY]

I received this schematic from a DIY website (I already forgot don't email me)

For high voltage rectifier & regulator
I plan for change 6Z4 to EZ81, 12B4A to EL84 and use original 12AT7

For filament bias
I plan for use shunt regalator 78l15 + uA741 + 2N3055 because it can supply voltage to parallel filaments (near 0 OHM) I think 7815IC can't supply continous current of filaments (It's very hot also included heatsink)

Any suggestion ?

[ray_moth]

I don't know about the 6Z4 but the EZ81 would not take at all kindly to a smoothng cap as large as 220uF. Max. is 50uF.

[Geek]

I once ran an EZ81 into 220uF. On the breadboard, I switched from SS diodes to tube and forgot to adjust the cap accordingly

I glowded it

[Dominique_free]

Have you try to replace the 2 silicon diodes by a vaccum voltage reference? Zener diodes are very noisy, and it is a noise that is very hard to cancel out.

If you want try it without buying a vaccum tube, you can use a cheap neon bulbe. Ask a electrician for that. You will get about 70 to 80 volts drop on it, not 120 volts, but the noise will be about 10 time less as with the zener. A such bulb is cheap to make a test, but you cannot use it in the long run, because each time you will power on the alimentation, you will get a different voltage drop on it.

With a reference voltage tube, you will get even less noise as with the neon bulbe, and the same voltage every time.

[kevinkr]

I use the 5651 gas tube reference in my designs, very stable and very little drift with temperature unlike a zener. One nice improvement to this design would be to LPF the reference by inserting a 470K resistor in series with pin 6 of the 12AT7 and adding something like a 0.22uF from pin 6 to ground.

You might also need to add a small grid stopper resistor (220 ohms) right at pin 2 and 6 of the 12AT7 to prevent VHF oscillations that can occur with this tube.

Also I recommend adding a 1K grid stopper on the grid connections 2 & 7 of the 12B4. Note that the 6BQ5 has similar issues and if triode connected I recommend a 100 ohm resistor screen grid to plate. I'd stick with the 12B4, its cheap and cheerful and does a good job.

Finally I would get rid of that 220uF first filter cap and replace with something < = to 47uF for rectifier life.

One other thing you could do to further reduce ripple on the output is to replace R14 with a choke. Say 1 - 10 H.

I don't follow your comments about the filament regulator at all. For parallel idht tubes a 7812 or 314 adjustable ought to be fine. A shunt regulator is just going to waste a lot of energy. If you need more current check out devices from Linear Tech.

[Mas Penk]

That's Power Supply for Jadis (Clone) Preamplifier, the very first tube project. 6Z4 is chinese tubes. I have the data sheets but cannot understand since it written in "Kanji" (chinese language).
The power supply it self has max voltage of 285V.

But since i realized that the sound is not my cup of tea then I change to another project,

You can get it at DIY Zone in Hongkong

[ANALOG GUY]

AHHH...good...I remembered...it was copied model.

First time I changed 6z4 to 6x4 but I have to change some pins of it, so I redesign for my style (6X4 + EL84 + 12AT7) with PROTEL99se.

Thx
analog guy

[kmtang]

Hi guys,

I have built the 280Vdc tube regulated PS according to HP400's design for my clone Marantz 7C line amp. It works great with extremely low noise.

Here's the link you can download the manual which includes the schematic.

http://www.mcmlv.org/Archive/TestEquipment/HP400.pdf

By the way, I added a CLC (4.7uF-2H-68uF) filter before the regulator tube. Also I used a paralled 6BL7 tube instead of the 12B4. At the HV output, I placed a 3.3uF Auricap as bypass filter.


Johnny