24 volt out of 9 volt batery

[Maik]

Hi,

I want to build the "preamp from hell", a 24 volt Randall RG100 red channel emulator.

http://sites.google.com/site/plexilandia/

I want to use it with a "9v to 25V converter circuit and to reduce 25V to 24V with a resistor (citing exactly)", as they said in the Randall topic.

Could someone make a pcb for this? I´m not too lazzy but I  don´t understand electronic that much...

Thanks!

Maik

[Taylor]

http://geofex.com/circuits/+9_to_33.htm

You don't really need to know much about electronics to do a basic PCB layout. You can start with the knowledge that you need to connect parts with copper traces that are connected with lines on the schematic. The first step is to learn how to read schematics, if you don't have that ability yet, and for that there are tons of websites and books that will help.

This would be a great opportunity for you to learn some things.   I really started to actually understand things when I started just looking at tons of schematics, reading, and doing layouts.

[Maik]

Yup, I know Taylor.
But...
There´s allways a "but", too much work and no time. I have to do my bachelor in facility management and school is only at weekend. So I have to study the whole time when not at work...
Perhaps next year!

I just want to steal some time to build this little Randall emu, cause I want to play my guitar in Thailand ithis summer on a hill without power suppy. I think it will be wonderfull when the day starts at 5 in the morning. Just me and the land...

[Maik]

Bingo Taylor, saw it and understood!!! Simple...or ok for me 

Now I build this little sucker

[yeeshkul]

How demanding is the thing  current-wise? Say i've got a pedal that needs 10mA, 24V and i decide to feed it with this circuit. Is a selection of a 9V power adapter crucial? Can a switching power adapter do any possible mischief? Thanks.

[deadastronaut]

 i wouldnt think the battery would last long...!

[Gurner]

My thoughts (just rough approximations)...

A fresh  9V alkaline battery can supply 550maH....but you're essentially tripling it to 24V ("ish", but you get the vibe!), therefore you need to divide the 550maH/3 = 180mAh .....now you've really got to lop off a bit for conversion inefficiencies (& the intial aspirational 550maH!!)....so I'd say it supply 140maH ......so in theory, I reckon you'd get about 14 hours for a circuit pulling 10mA @24V- but being a realist/pessimist ("the glass is half empty you ****") ...bank on 10 to 12 hours!

[petemoore]

  Consider .
  A couple 12v batteries

[yeeshkul]

Guys i wasn't considering batteries at all. I was considering a power adapter with a particular current draw. As i see it is not that dramatic

[Mark Hammer]

There ARE 24vdc wallwarts out there.  I think I even have one or two.  Forget about the battery voodoo, and do this right.

[Maik]

 
No, it´s just because I want to play on a hill. The thing is in summer there will be 45° / 113 F and the air is wet. So I don´t want to carry my things and a power generator, it will be a loud one in Thailand  
So I need batteries or I have to drink so much beer that I can´t go up the hill.

This is the hill

http://img829.imageshack.us/i/berginchaam.jpg/

[Gurner]

To be clear.. (I think this thread quickly got it's wires crossed)...my earlier calculations were for battery life for a 9V battery running at 24V ...for a pedal that draws the aformentioned 10mA!!! I have no idea what the current draw is for the Maik's intended circuit...and therefore the battery life predictions should be disregarded.

hip to my groove Daddio?

[Mark Hammer]

No, it´s just because I want to play on a hill. The thing is in summer there will be 45° / 113 F and the air is wet. So I don´t want to carry my things and a power generator, it will be a loud one in Thailand  
So I need batteries or I have to drink so much beer that I can´t go up the hill.

This is the hill

http://img829.imageshack.us/i/berginchaam.jpg/

Okay.  Better understood now.  Consider using an 8-pack of AA or AAA batteries (for 12vdc) and using a doubler circuit.  The required diodes will probably give you 23v, but I doubt the extra volt will make a difference.  You would be surprised how long an 8-pack like that can last, even with high current draw.

[thedefog]

No, it´s just because I want to play on a hill. The thing is in summer there will be 45° / 113 F and the air is wet. So I don´t want to carry my things and a power generator, it will be a loud one in Thailand  
So I need batteries or I have to drink so much beer that I can´t go up the hill.

This is the hill

http://img829.imageshack.us/i/berginchaam.jpg/

THAT LOOKS AWESOME! You should get a whole band up there.

[Gurner]

You don't need 24V .....you need an oxygen mask.

[yeeshkul]

All right, i'll try to ask a different way. You have a pedal that draws 10mA and needs 24VDC, all right?

You can either get a power source that provides 24VDC and can handle 10mA, which is almost any power source but this is just example ...
OR
You can use the above mentioned voltage converter fed by a 9V power source, anyhow weird it seems to be.

And now my question:
Since the converter doubles the voltage, it has to "pay" for that with something. That something may be a current draw - just my guess.
Am I right? If i am right, can you guess how much more current it needs?

[Maik]

Ok Mark, I will think of it 
Think I will do it with 12 Volt and double it.