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Negative 12 volts internally for a eurorack distortion modul
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Negative 12 volts internally for a eurorack distortion modul

by BitBucket on Sat May 27, 2017 7:04 pm

Hi, I read this on a muffwiggler forum:

"i find the overdrive from the a-119 to be my favorite overdrive with a 303 that i have tried. i've also tried boss distortion, boss overdrive, ehx big muff, ehx microsynth, and truly beautiful disaster, the 119 is still my favorite overdrive/distortion with a 303 compared to all of those pedals. does anyone know anything else that is similar, or built the same? some of the pedals i've compared it to are way expensive, the 119 is 99 bucks!"

He's talking about a Doepfer A-119 Eurorack module.

I'm thinking of building this into the x0xb0x case but I have no idea how to generate the -12v (I think it needs about 30mamps).

BitBucket
 
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Re: Negative 12 volts internally for a eurorack distortion m

by antto on Sun May 28, 2017 3:36 am

so this distortion is meant to run on +/-12VDC?

first of all, i'd check if the module can run on a lower voltage, like +/-6VDC

the 303/x0xb0x use a total of 12V for the audio circuits, where 5.333V is used as (buffered) virtual ground
if you want to incorporate some audio circuit into the x0xb0x you'd use the "5.333V" line as your ground, "GND" as your negative supply line, and "+12V" as your positive supply line
thus your supply voltages would be -5.333V, 0, and +6.667V
so it's slightly not symmetrical, but that isn't too bad if you don't abuse it
[EDIT] ehm, this explanation might be wrong, if your audio circuit includes a chassis, and the chassis is connected to "ground" then it'll end up being connected to the 5.333V which is not good
i think the proper way to do it is to analyze the distortion schematic and adapt it to be incorporated into the x0xb0x

another option you have is to use the 9VAC from the x0xb0x IO board, and make your own AC->DC circuit

antto
 
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Re: Negative 12 volts internally for a eurorack distortion m

by BitBucket on Sun May 28, 2017 3:53 am

Yes, thanks antto, the module needs +/-12VDC.

Perhaps it is best to keep it external, it may be more useful in the future, although I'd still need some help with a power supply circuit; Eurorack power supplies are expensive.

BitBucket
 
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Please be positive and constructive with your questions and comments.