Voltage Multipliers (for our tube projects...)

[g.]

i don't think so...

best is to use the EH toroidal transformer

[earthtonesaudio]

Is it possible to obtain like 400-422v with this system? I would use it to build a tube dual rectifier preamp - 4 12AX7s.

Depends greatly on the load.  I saw a circuit very similar to this one produce greater than 1kV (measured with an electric field meter), but then the 10Mohm input of a digital multimeter dropped it down to something like 300V.

[juancra]

Hi pals!

I'm following this thread a time ago because i'm interested in building a tube miniamp for bedroom practice.. but something hangs me out. I don't fully understand which is the amperage rating of this or other nixie supply units... Let's say if I power the whole thing from 1A 220 / 12v transformer, it would deliver 1A or it will shrink to the 10ma rating posted pages ago?. Could I use this nixie smps to power a SE tube power amp?

Hope you can help me
Sebastian.-

[blackcorvo]

why not only use a 12v/2A transformer and connect it to a normal recticifier (for filaments) and to a voltage multiplier circuit? you can easly power a small amp from it without problems, and it won't take much space if you know how to project a pcb.

[juancra]

Yes! After watching carefully this proyect (http://www.jjs.at/electronic/class_a_subminiature.html) I found out that I could feed the heathers by other means than using precious mA from the SMPS. thanks for the answer!

[JKowalski]

Hi pals!

I'm following this thread a time ago because i'm interested in building a tube miniamp for bedroom practice.. but something hangs me out. I don't fully understand which is the amperage rating of this or other nixie supply units... Let's say if I power the whole thing from 1A 220 / 12v transformer, it would deliver 1A or it will shrink to the 10ma rating posted pages ago?. Could I use this nixie smps to power a SE tube power amp?

Hope you can help me
Sebastian.-

You cant get more power out of your wall wart then you put into it.... A 12V 1A transformer can supply 12 watts of power. Multiply voltage by current to get power.

At an ideal 100% efficiency voltage conversion, you should be able to get any voltage + current rating that when multiplied together equal 12 watts.... So You could get 48 volts, 250mA, 6V 2A,120V 100mA...

So you see, at high voltages you get very little current but it's still the same power. Of course, nothing is 100% efficient at power conversion, so you lose a decent amount of available watts in the process.



If you are making a tube amp with this you are limited by the amount of current the wall wart can supply, the amperage + voltage rating of your switching power supply.

I believe it was said 300V 100ma, so multipy those two together and you get 30 Watts. That doesnt mean you can make a 30 watt amplifier out of it, though... amplifiers use up current in many more ways than just straight out the speaker (especially tube, with their filaments) If you want the full available output power, then you would need your 12v wall wart to be... 30 watts / 12V = 2.5A. 12V 2.5A Wall wart.

EDIT: Oops, it was 10ma. Thats 300V x 0.01A = 3Watts. Not enough to power a decent tube amplifier unless it is like a <1Watt... sorry.

You need to do your homework on your amp and calculate an estimate for power waste + speaker out, decide on your minimum power supply specs - and then find something above those (you don't want your amp barely getting by, you want some margin of safety)

[juancra]

Yeah.. I don't think that this is viable for an all tube amp... All of this came by because I found, on a local store, an amount of nos tubes and wanted to build a cheap test bed to run tests on them.. but think I'll buy a commercial power trans instead =)

Thanks for the info!

[Renegadrian]

I successfully built the 555 smps - I used the verified layout from Rick, then I tried to do a Vero version too...
Ended up to be a close copy of the perf one...Should work!

[MichelP]

And does the vero layout  work?  I´m waiting for deliveries of the mosfets and want to make one too !

[Renegadrian]

IT IS VERIFIED!

[MichelP]

Cool !  I'll  make one next week and report back.  Ciao

[MichelP]

Hi Renegadrian

The parts came, I used your layout and it works : from 120 V to 270 V  (without load) !

Have anyone allready used this power supply in a pedal, I´m thinking of the Real McTube .

Ciao

[Renegadrian]

Glad it worked out fine - I told ya!!! 

[MichelP]

As promised, I made the real McTube with Renegadrian´s layouted power supply.  A perfect couple ! 

[Renegadrian]

yes! pics please!!!

[MichelP]

Hi Renegadrian,

When I come home this evening I'll send you some pictures.  Don't expect too much though, I built the Real McTube on a (real) piece of breadboard.

It's really cool that I can dial in the voltage as given in the schematic.  Yeah that SMPS is really flexible.  The SMPS doesn't get hot, not even warm after 2 hours.

I did some listening at low levels : through my Laney VC30 and (in my workplace) a Vox plugg-in.  Fuzzy distortion with a tube-depth.  Again at low level. 

I tried it with 2 valves an old China ECC83 and a Sovtek ECC83 WA. The difference was noticable, so further testing and listening ahead !

[Scruffie]

I made a vero for the MAX1771 Charge Pump, i've spaced it out a bit more as I think it might be a bit more sensitive to stray capacitance than others on vero... (or is the opposite right and I shoulda made it smaller... will probably make a smaller one later anyway) only one way to find out though! Unverified as of yet.


(All thanks go to Rick Holt & Nick The Designer)

[MichelP]

Here's (as promised) a picture of my preliminary build Real McTube.  Fully functional, waiting for a box.

[frequencycentral]

With the MAX1771 smps you may want to use high amperage rated inductors such as these from Rapid: http://www.rapidonline.com/Electronic-Components/Inductors-And-Chokes/Leaded-Inductors/High-current-leaded-suppression-chokes/79278/kw/

Also worth uprating the reservoir caps voltage capability if you plan to tweak the smps in anyway - I was getting 500v out of mine at one point. Banzai sell some quite small 350v 4.7uF caps: http://www.banzaimusic.com/Roederstein-EKA-4-7uF-350V.html

You can tweak up the maximum available voltage by screwing around with the trimmer and it's two resistors, I ended up using 180k/1k trimmer/1k instead of 1M/5k trimmer/10k.

Good luck with building onto veroboard - that's a lot of copper strips to act as aeriels. In the MAX1771 thread Nick Desmith posted:

You are actually quite lucky it worked on a proto board - MAX1771s are pretty sensitive to stray capacitance and you may have a few unexpected high frequency artifacts in there

I found the 1771 smps to work on breadboard but was highly unstable. On perf it works very well IMO. Better still would be a PCB with large ground plane. Nick Desmith on his PCB layout:

You can see the shadow of the ground plane on the underside and note that several vias in parallel have been used to connect Rsense to the ground plane - each via can typically handle a few 100 mA, and as up to 2A can flow through Rsense we need to provide a good low impedance path to ground.

[Renegadrian]

translated from HERE

A power supply to feed nixie tubes and PIC. It goes at 12V and it will charge up to 180V.
max current is 11mA. this schem uses the MAX771.
resistors must be 1/4W 1%. The mosfet doesn't get hot so heatsink is not needed.
220uH must be max 100mA.

(obviously the PIC part is not needed for our circuits, so it can be deleted)

http://www.cavva.hiponet.it/schemi%20elettronici/alimentatore%20nixie.jpg



http://www.electricstuff.co.uk/nixpsu.html
http://www.desmith.net/NMdS/Electronics/NixiePSU.html