Tube mic universal power supply

[djn111]

Hello,

I was wondering,

This afternoon I was playing with Duncan's PSU designer II and was thinking wy not make a PCB design based on the program, that way you can design a PSU on your computer, and build/test it on a PCB.

I was thinking in the following lines, three AC inputs, high voltage, heating supply for the mic tube, and heating supply for a recetifier tube (if wanted).

Two posibilities for the High voltage recetifier, tube (9 pin and 7 pin noval, octal ?) or solid state.

Heater voltage for the mic tube, recetifier, the choice for a voltage regulated or current source supply (my favorit), enough space for some bulgy capacitors.

High voltage, max of three RC/LC stages, you can make it death silent with that, with carefully choosen R, C and L

Let me know you opion or suggestions.

DJN (duncan's power supply designer II is free to download use google).

 

[pucho812]

How do you work it? I have played with the program before and could never get it to work.

 

[djn111]

There is a help, but start it up.

You can choose with a right click what you want to change, value etc, ad a block RC LC etc, change load, resistor constant current.

Watch the simulation time, the first is in mili seconds so 1000 equels 1 second, after that the delay is in seconds.

Choose what you want to see probably the last C voltage to check for ripple.

First make a simulation, if you are happy with the result (not that big of over shoot killing your first capacitor), make a delay for the time it takes to get stable, make sure you use a long enough simulation time. now you can check out the ripple, after pressing the magnifing glass with the red x and maybe adjust a bit with the other two.

DJN

 

[Gus]

Why do you need software for a simple power supply design?

 

[djn111]

What is simple ?

To make it right try it, for Hi voltage there is a lot more going on, the four resistor + 4x 220uf is not optimal.

I can make a death quit power supply for a Mic with only two stages.

DJN

 

[Kingston]

Seems to me if you can't get dead quiet tube B+ line with four stages of RC with 220uF each you have a very serious design error elsewhere.

Tube mic PSU's should be simple. No point wasting time over-thinking this one.

 

[djn111]

Hi,

Yes I agree with you, but would it not be easy to have one PCB to fit 99% of all your needs, to build a tube PSU of your liking ?

DJN

 

[s2udio]

Why do you need software for a simple power supply design?

+1
??Why use your brain ,when you can do it on computer??

 

[djn111]

Oke no interest, post closed.

Just asking, can you calculate for me the ripple of the following: AC supply 2x 220V, rectifier EZ81, load 23.9mA, first resistor 220 ohm, first capacitor 16uF, second stage inductor 10H internal resistance 130 ohm, cap 64uF after 10 seconds switch on ?

And in one second the same, changing the the resistor to 270 ohm ?

Audio pro or not, won't work properly without a good power supply design.

I don't use my brain that is the reason I am a electronic engineer trying to make live easier.

DJN

 

[gemini86]

There's no reason to belittle one of our own here guys... Let's not be gearslutz. The duncan amps tools are good time-savers, and good for people who don't have a gift with math (ME).

djn: Such a simple RC/LC filter can be done cheaply on vero, with no more time than it takes to populate a circuit board. Making a pcb just for that would actually ADD cost. Although if you wanted, you could probably use just about any universal psu board, and just bend a few component legs to fit, or mount large caps off-board.

 

[djn111]

Yes, I am with you on that one, It was just a thought, I read a lot of people with power supply problems, sure I can build a tube power supply point to point now sweat, but a lot of members don't and for those, not a only making electronics by numbers was the pcb idea for. But it end here, and no hard feelings on my side to anyone around her.

DJN

 

[pucho812]

. Let's not be gearslutz.

+infinity...

 

[zayance]

+infinity...

... and beyond.....

 

[Kingston]

+infinity...

... and beyond.....

Haha!

but would it not be easy to have one PCB to fit 99% of all your needs, to build a tube PSU of your liking ?

I suppose yes. Something like CRCRCRC for B+ and another with one more RC step for heaters. Any resistor could be replaced with a choke for better filtering.

Make sure to provide enough space and several lead sizes for various standard cap and resistor size. Perhaps pattern selector could be part of this universal PCB.

Just one problem. It ends up quite big with all the options that might go unused for many mics. Another issue is that for mics with indirect heating a whole half of the PSU will be completely unused (heaters). Not a big deal of course but I'm personally not a fan of physically massive PSU's for mics if they can be avoided.

As a side note, take a look at this PCB that was designed for a certain MK7 microphone project. It's public domain so you can do whatever you want with it. Reasonably universal for any B+ with DC heaters and pattern select design. Would even work for U47 variants, but like was mentioned, one side would go unused.