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DIYstompboxes.com  |  DIY Stompboxes  |  Building your own stompbox  |  Voltage Multipliers (for our tube projects...) 0 Members and 1 Guest are viewing this topic. « previous next »
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Author Topic: Voltage Multipliers (for our tube projects...)  (Read 66165 times)
frequencycentral
Posts: 4890


Kicking the sh!t of of your speakers since 2008


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Re: Voltage Multipliers (for our tube projects...)
« Reply #100 on: October 30, 2009, 11:13:07 AM »

A verified layout for the Nixie SMPS, I just built and tested it today. It's putting out 313 volts without a load. I haven't added the snubber yet, I want to experiment with that part. The snubber is made up of the 2.2K resistor and the 100pF cap in the Nixie schematic. I've an idea that changing the snubber values slightly will keep the B+ higher, so I thought I'd build the main part and hook it up to my breadboard to test different filterings. I used two 100uF caps instead of the 330uF, mainly to save on space.

Here's the link to the original file again: http://www.ledsales.com.au/kits/nixie_supply.pdf





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tranceracer
Posts: 628

Byron K


Re: Voltage Multipliers (for our tube projects...)
« Reply #101 on: October 30, 2009, 12:56:44 PM »

Very nice!
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Ice-9
Posts: 1585


Mick T


Re: Voltage Multipliers (for our tube projects...)
« Reply #102 on: October 30, 2009, 03:05:15 PM »

Thats looking really good Rick, and 313v as well. Were did you get that inductor i think i will build this SMPS to try with one of my 12ax7 designs.
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frequencycentral
Posts: 4890


Kicking the sh!t of of your speakers since 2008


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Re: Voltage Multipliers (for our tube projects...)
« Reply #103 on: October 30, 2009, 03:15:48 PM »

Thats looking really good Rick, and 313v as well. Were did you get that inductor i think i will build this SMPS to try with one of my 12ax7 designs.

Thanks guys. The inductor is this one: http://www.rapidonline.com/Electronic-Components/Inductors-And-Chokes/Leaded-Inductors/High-current-leaded-suppression-chokes/79278/kw/

The SMPS is for my next amp. I've got some 12AX7 and 12AU7 left over from my Valvecaster builds last year, and I bought a bulk lot of Fender Reverb Transformers (for my Murder Ones), so I thought I'd try a SE amp with 'proper big tubes' and a SMPS.

Just for fun, I connected the SMPS to a 9 volt battery today - and got 254 volts! I titter'd me t!ts off! Completely useless to consider a 9 volt battery powered tube amp though.
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tranceracer
Posts: 628

Byron K


Re: Voltage Multipliers (for our tube projects...)
« Reply #104 on: October 30, 2009, 09:46:42 PM »

Just for fun, I connected the SMPS to a 9 volt battery today - and got 254 volts! I titter'd me t!ts off!

LOL!  Cheesy 
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Ice-9
Posts: 1585


Mick T


Re: Voltage Multipliers (for our tube projects...)
« Reply #105 on: October 31, 2009, 12:24:51 PM »


Just for fun, I connected the SMPS to a 9 volt battery today - and got 254 volts! I titter'd me t!ts off! Completely useless to consider a 9 volt battery powered tube amp though.

Yeah ! but to get 254v from a 9v battery is just something you have to try just to see it for real. Lol
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frequencycentral
Posts: 4890


Kicking the sh!t of of your speakers since 2008


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555 SMPS with negative charge pump section
« Reply #106 on: November 01, 2009, 12:04:09 PM »

Here's a variation on the 555 SMPS with the addition of a negative charge pump section. Probably of interest to only one person on the planet (me), but developed so I can play with negative grid biasing my 5902 beam pentodes. Verified today on the breadboard. The red stars indicate where it is possible to tap off -11.5 volts and -22 volts, possibly useful for negative grid biasing other tube types.

« Last Edit: November 01, 2009, 12:10:51 PM by frequencycentral » Logged

earthtonesaudio
Posts: 3596


Alex


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Re: Voltage Multipliers (for our tube projects...)
« Reply #107 on: November 02, 2009, 06:34:22 AM »

Does this require a heatsink for the FET?
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I gotta cut down on my (ab)use of parentheses.
frequencycentral
Posts: 4890


Kicking the sh!t of of your speakers since 2008


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Re: Voltage Multipliers (for our tube projects...)
« Reply #108 on: November 02, 2009, 12:22:55 PM »

Does this require a heatsink for the FET?

Yeah, the IRF740 gets pretty hot. Without thermal dissipation it would eventually burn out I believe. I used the simplified version (ie without the negative charge pump) in my Superfly, there are pics of the heatsink I used in that thread: http://www.diystompboxes.com/smfforum/index.php?topic=78302.0
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maarten
Posts: 138


Re: Voltage Multipliers (for our tube projects...)
« Reply #109 on: November 04, 2009, 10:00:58 AM »


Hello Rick,
why did you move the 2K2/100p to the other side of the 1N4004?
Maarten
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frequencycentral
Posts: 4890


Kicking the sh!t of of your speakers since 2008


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Re: Voltage Multipliers (for our tube projects...)
« Reply #110 on: November 04, 2009, 11:52:13 AM »


Hello Rick,
why did you move the 2K2/100p to the other side of the 1N4004?
Maarten

Bummer! My mistake, I'll correct the layout and schematic...... icon_confused
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Cliff Schecht
Posts: 1187



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Re: Voltage Multipliers (for our tube projects...)
« Reply #111 on: November 04, 2009, 11:53:44 AM »

It looks like a snubber circuit to me which goes in parallel with the FET's drain and source terminals. Or in this case, because you've got voltage-mode control, it goes from the drain to ground. These can increase efficiency in the FET by 20-30%, sometimes more with excessively ringing circuits!
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frequencycentral
Posts: 4890


Kicking the sh!t of of your speakers since 2008


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Re: Voltage Multipliers (for our tube projects...)
« Reply #112 on: November 04, 2009, 12:06:06 PM »


Hello Rick,
why did you move the 2K2/100p to the other side of the 1N4004?
Maarten

Bummer! My mistake, I'll correct the layout and schematic...... icon_confused

Ok, both the layout and schematic (above) are now corrected. You may need to refresh your browser to see them. Oops.  icon_redface
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g.
Posts: 154



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Re: Voltage Multipliers (for our tube projects...)
« Reply #113 on: November 05, 2009, 04:24:24 AM »

thanks for sharing !
i'm curious,
how many mA this supply can output ?

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frequencycentral
Posts: 4890


Kicking the sh!t of of your speakers since 2008


WWW
Re: Voltage Multipliers (for our tube projects...)
« Reply #114 on: November 07, 2009, 03:52:33 AM »

^
^
Not sure how to measure for how many ma it puts out.  Embarrassed

I was thinking that it should be possible to double the ma output by dupilcating the IRF740, snubber, inductor, diode and reservoir cap. ie two parallel SMPS running from the same 555. Obviously the current draw would be significantly higher, but using each of the parallel outputs to drive one dual triode (in a two dual triode design) should give significantly higher voltages and increased performance before saturation of the inductors occurs.
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crystal
Posts: 2


Re: Voltage Multipliers (for our tube projects...)
« Reply #115 on: November 10, 2009, 02:17:14 AM »

Neat design, but I do wonder why you've connected the negative grid biasing circuit to the gate of the mosfet. As long as there is virtually no load on the negative rail you will be fine else it will reduce the efficiency of the mosfet because the gate isn't driven hard enough. Wouldn't it be better to connect the negative charge pump to the drain of the mosfet?
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Cliff Schecht
Posts: 1187



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Re: Voltage Multipliers (for our tube projects...)
« Reply #116 on: November 10, 2009, 02:45:05 AM »

^
^
Not sure how to measure for how many ma it puts out.  Embarrassed

I was thinking that it should be possible to double the ma output by dupilcating the IRF740, snubber, inductor, diode and reservoir cap. ie two parallel SMPS running from the same 555. Obviously the current draw would be significantly higher, but using each of the parallel outputs to drive one dual triode (in a two dual triode design) should give significantly higher voltages and increased performance before saturation of the inductors occurs.

You would have to sync the two oscillators to prevent beat frequencies from occurring. Just being 30 Hz off is enough to give you audible noise..

Also, I'm not sure how well a direct duty cycle supply will handle being paralleled. Current mode supplies are good at this because both can sense when the load has changed and will adjust accordingly. Direct duty cycle control OTOH just knows that more current = more duty cycle. One of the supplies may be able to try to pull too much current and fail. It may not be a problem with what you're trying to do but it's something to be aware of with simple switchers like these.
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niopren
Posts: 56


Re: Voltage Multipliers (for our tube projects...)
« Reply #117 on: November 10, 2009, 10:32:05 AM »

thanks for sharing !
i'm curious,
how many mA this supply can output ?



Nixie PS max. 10ma
just for one or two 12a*7



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g.
Posts: 154



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Re: Voltage Multipliers (for our tube projects...)
« Reply #118 on: November 11, 2009, 04:30:21 PM »

i found this one : here http://www.unitechelectronics.com/NE-555.htm



Quote
A simple circuit to power a NEON lamp. Primarily used to test neons where safety is a requirement.
   The R1 - R2 - C1 circuit determines the NE-555 to oscillate  producing a voltage at Pin 3 driving
   the small 8 ohm transformer's primary windings, the secondary windings are 1K ohms. It works.
   This results in a ratio of 125 times gain, however we all know that's not going to fly. Losses ??
   The  theoretical voltage of 500 Volts AC passing through R3 10K dropping to around 180V AC
   thus striking the gas within the neon and lighting it.  This circuit was designed for pocket use.
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manis404
Posts: 32


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Re: Voltage Multipliers (for our tube projects...)
« Reply #119 on: November 12, 2009, 11:42:47 AM »

Is it possible to obtain like 400-422v with this system? I would use it to build a tube dual rectifier preamp - 4 12AX7s.
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Sometimes to do it right, you have to Do It Yourself.
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