Looking at Sound Devices portable pre's (the mixpre, the 302, etc.) They get 48v phantom power from 3 AA's. How? I follow the voltage double schemes, but it seems you need AC to go from one voltage to another. Would you use a chopper or something to chop the 4.5 volts of the batteries and then use a voltage multiplier?
48v from 3 AA's
- Thread starter kidtexas
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Svart
Well-known member
pwm charge-pump? easy to do with batteries, that's how cell phones do it...
SSLtech
Well-known member
I think I have a link to one method somewhere...
http://ourworld.compuserve.com/homepages/Bill_Bowden/page4.htm#triple.gif
..I think it'd do nicely. It uses a 12VAC transformer backwards to step up to about 80V, then you can regulate down...
Keith
http://ourworld.compuserve.com/homepages/Bill_Bowden/page4.htm#triple.gif
..I think it'd do nicely. It uses a 12VAC transformer backwards to step up to about 80V, then you can regulate down...
Keith
NewYorkDave
Well-known member
Pulse-width modulation
I have some voltage-multiplier schematics somewhere that use standard cmos inverters to acheive quite high voltages..
I'll scan when I find them..
Jakob E.
I'll scan when I find them..
Jakob E.
owel
Well-known member
Check this out... using MAX1044 ICs
http://www.geofex.com/circuits/+9_to_33.htm
http://www.geofex.com/circuits/+9_to_33.htm
SonsOfThunder
Well-known member
Hey!
From another thread: "What would I use a switching supply for?"
Here ya go, this is why...:grin:
From another thread: "What would I use a switching supply for?"
Here ya go, this is why...:grin:
BradAvenson
Well-known member
http://www.rolls.com/data/pb224man.pdf
There is a schematic in the manual on the rolls site. It uses CMOS inverters like jakob mentioned.
There is a schematic in the manual on the rolls site. It uses CMOS inverters like jakob mentioned.
b3groover
Well-known member
[quote author="kidtexas"]Looking at Sound Devices portable pre's (the mixpre, the 302, etc.) They get 48v phantom power from 3 AA's. How? [/quote]
I don't know how they do it, but I'd like to ask why? Seems like your phantom power would last, oh, about 3 minutes!
I don't know how they do it, but I'd like to ask why? Seems like your phantom power would last, oh, about 3 minutes!
[quote author="b3groover"][quote author="kidtexas"]Looking at Sound Devices portable pre's (the mixpre, the 302, etc.) They get 48v phantom power from 3 AA's. How? [/quote]
I don't know how they do it, but I'd like to ask why? Seems like your phantom power would last, oh, about 3 minutes![/quote]
I think they can get a couple hours off of a set of batteries. On the Mixpre, powered by 2 AA, they "say" you get 2 hours powering two 48v mics, a loud headphone amp, and 2 LED VU's (never mind all the mix electronics). Not too bad if you ask me.
I don't know how they do it, but I'd like to ask why? Seems like your phantom power would last, oh, about 3 minutes!
[/quote]I think they can get a couple hours off of a set of batteries. On the Mixpre, powered by 2 AA, they "say" you get 2 hours powering two 48v mics, a loud headphone amp, and 2 LED VU's (never mind all the mix electronics). Not too bad if you ask me.
OK - I got the article scanned:
http://www.gyraf.dk/schematics/Voltage_multipliers_with_CMOS_gates.pdf
It's somewhat different from what I've seen in other places - but it's simple and very easy to scale.
Maybe a tube-mic powersupply could be built this way?
It is at the Gyraf/Resources page:
http://www.gyraf.dk/schematics/schematics.html
Jakob E.
http://www.gyraf.dk/schematics/Voltage_multipliers_with_CMOS_gates.pdf
It's somewhat different from what I've seen in other places - but it's simple and very easy to scale.
Maybe a tube-mic powersupply could be built this way?
It is at the Gyraf/Resources page:
http://www.gyraf.dk/schematics/schematics.html
Jakob E.
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