Volca beats mod in to Euro power supply ?????

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cynical
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Volca beats mod in to Euro power supply ?????

Post by cynical »

Hello people
I am trying to make my Volca powered from my Eurorack power supply , and here is what i have find out (and maybe wrong). I need a voltage regulator and a resistor to decrease the +12V to +9V but, since i am newbie here are some unresolved question that i have.

1st were i am going to put the regulator and resistor? ( a thought was on the + battery point on the PCB ).

2nd can i put a cable on the GND point of Volca to connect the GND of power supply there?

3rd Has anybody done something similar to this and ca give me guidelines ?
Last edited by cynical on Sun Oct 25, 2015 12:12 pm, edited 1 time in total.
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PWM
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Post by PWM »

How many question marks does one need?


Google; 7809 connection. You'll find your answer there.
https://www.google.nl/search?q=7809+con ... 4UCh0qAQny

Don't forget the bypass caps connected between the input and ground, output and ground of the regulator. 100nF should work fine.

You could place a 10 Ohm resistor before the regulator. Like this;
+12V -///- voltage regulator input.
-///- being the resistor.
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cynical
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Post by cynical »

PWM wrote:How many question marks does one need?


Google; 7809 connection. You'll find your answer there.
https://www.google.nl/search?q=7809+con ... 4UCh0qAQny

Don't forget the bypass caps connected between the input and ground, output and ground of the regulator. 100nF should work fine.

You could place a 10 Ohm resistor before the regulator. Like this;
+12V -///- voltage regulator input.
-///- being the resistor.
Have you done something similar ? could that be a schematic ?
also i saw that the caps values should be 100nF not uF.

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PWM
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Post by PWM »

I have done, loads of times. Not for the Volca's, though.

That's why I said 100nF..?
What you've drawn should be fine. You could get rid of 1 of the caps at the output, and make those 100nF. (If they where 100uF they would be polarized)
Also, you've drawn your resistor to be a 10k, that should be a 10 Ohm.
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jmagin
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Post by jmagin »

You don't want the 10 ohm resistor. In the three-terminal regulator, the internal pass transistor is the circuit element that the voltage drop is developed across. With a series resistor on the input, you'll just mess up its ability to regulate effectively. See figure 6 in the datasheet:
https://www.fairchildsemi.com/datasheets/LM/LM7809.pdf

It is true that a maximum of 3V * 600mA = 1.8 watts may be dissipated in the regulator, so attach a heatsink of some sort. Well, the adapter they sell for the Volcas is rated 600mA, maybe it doesn't use that much typically.
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Post by flts »

mmagin wrote:It is true that a maximum of 3V * 600mA = 1.8 watts may be dissipated in the regulator, so attach a heatsink of some sort. Well, the adapter they sell for the Volcas is rated 600mA, maybe it doesn't use that much typically.
The peak consumption is around 80mA @ 9V: http://matthewzipkin.com/tvv/ ... So doesn't really draw that much current.
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jmagin
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Post by jmagin »

flts wrote: The peak consumption is around 80mA @ 9V: http://matthewzipkin.com/tvv/ ... So doesn't really draw that much current.
Cool. I was being pessimistic. That's a lot closer to what I would have expected!
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nurbivore
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Post by nurbivore »

It sounds like you want to do things even more DIY, but for the sake of future searchers, I just wired in one of these to power my Beats and Keys, and haven't had any problems. My only complaint is that the Volcas don't have real power switches, so I have to turn each one on individually in addition to the power.[/url]
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