# MDMA Od at 18V?



## Yoyo (Sep 1, 2020)

Hi,

I just completed to build the MDMA od, i’m very happy with it, it sound great with lot of bass. I like to run my pedals at 18V when it’s possible, can you tell me if i can do it with this MDMA Od ?

Here is the list of components i put :

- 6 electrolytic caps Panasonic FC 50V DC
- 1 Jamicon SHR 50V DC
- 1 Greenie 100V DC
- 3 Silver Mica 500V DC
- 2 Wima MKS2 63V DC
- resistors 1/4W i think but not sure

I have a doubt on the Opamp, it is the MC1458, i found the datasheet but i’m a newbie and can’t understand informations on this.

Thank you very much for helping me.

Best regards.


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## zgrav (Sep 1, 2020)

Looks like you're good to go for running that pedal at 18v.


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## Nostradoomus (Sep 1, 2020)

Yep you’re good to go, 1458 can handle up to 30v


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## Yoyo (Sep 1, 2020)

Thank you very much for answering so fast! I'm very happy i will try it tomorow! Just to know can you tell me what i have to search on the datasheet of the MC1458P to find this information?

Thanks zgrav and Nostradamus, thanks PedalPCB team to provide us good PCB.


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## Nostradoomus (Sep 1, 2020)

I just brought it up on Mousers website as they list the data sheet info on the item page. Also the original Wampler pedal says 9-18v on it.


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## Yoyo (Sep 1, 2020)

Ho thank you, i download the datasheet on mouser but didn't have the idea to just check below on the website.... ?

Anyway thanks guys, if my pedal explode tomorrow i will give you a feedback ;-)


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## moonlightpedalbuilds (Sep 21, 2020)

Can this https://www.pedalpcb.com/product/3pdt-chargepump/ work on this pcb?


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## zgrav (Sep 21, 2020)

are you already running your pedals at 18v?  or are you running pedals at 9v that all have charge pumps in them? 

you could use that add in board to run the PCB at 18 volts (assuming that all of your capacitors are rated higher than 18v, preferably at least 15 v.  your list at the top shows you meet those requirements), BUT you would not want more that 9v coming into the extra board with the charge pump on it.


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## Yoyo (Sep 21, 2020)

Hi all,

I tried my MDMA at 18V and it works perfectly, i'm still alive! I prefer under 9V for high overdrive and at 18V for clean boost and very light opamp crunch because it saturate lately and more softly.

Thanks for your help


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## moonlightpedalbuilds (Sep 22, 2020)

zgrav said:


> are you already running your pedals at 18v?  or are you running pedals at 9v that all have charge pumps in them?
> 
> you could use that add in board to run the PCB at 18 volts (assuming that all of your capacitors are rated higher than 18v, preferably at least 15 v.  your list at the top shows you meet those requirements), BUT you would not want more that 9v coming into the extra board with the charge pump on it.



I only have 9v output on my power supply.


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## zgrav (Sep 22, 2020)

pedjok said:


> I only have 9v output on my power supply.


got it.  

with multiple comments on the thread about pedals running at 18v this was worth clarifying.  plugging a pedal with a charge pump into a 12v or 18v power supply can fry the charge pump.  some pedals have protection like a 15v zener diode to protect against accidental damage like that, but not all of the charge pump pedal designs mitigate that risk.


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## Gt6371 (May 21, 2022)

Can someone help me out? I’m starting the build for the MDMA and it calls for a 100u cap. It’s pretty big and I wouldn’t have room enough room for the IC.  Am I missing soemthing?


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## zgrav (May 21, 2022)

you need the 100U cap, but it likely would be OK at 25 volts.  What is the voltage on your 100U cap?  If it is higher, that is why the cap is bigger.


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## Gt6371 (May 21, 2022)

Yes it is 50volts.


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## Gt6371 (May 21, 2022)

I’ll order some at 25volts. I’m still learning I’m a newbie. Appreciate your help.


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## Gt6371 (May 21, 2022)

I actually had some. Sweet!


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## giovanni (May 21, 2022)

Gt6371 said:


> I actually had some. Sweet!


You can also install all other components and then the cap last and make the legs long enough to fit above the other parts. Not the prettiest thing but it works in a pinch.


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## JamieJ (May 22, 2022)

Also you can sometimes mount them on the other side of the board if there is space underneath.


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