# 18v charge pump PCB with Brown Betty



## sodapop808 (Jan 25, 2021)

Hi everyone
I'm going to use one of the new charge pump boards with a brown betty.  Should I jumper the schottky 1N5817 diode (D5) on the BB PCB and, assuming all of my parts are rated to minimum 18v (all of mine are 25v minimum) be fine?


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## Barry (Jan 25, 2021)

I think 35v is the recommended


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## zgrav (Jan 25, 2021)

35 v is good.  you would be OK using 25 if you had them but didn't have 35v.  I would not push it with 18v caps if you want to use the charge pump.  18v would be fine to run the pedal at 9v.


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## music6000 (Jan 25, 2021)

sodapop808 said:


> Hi everyone
> I'm going to use one of the new charge pump boards with a brown betty.  Should I jumper the schottky 1N5817 diode (D5) on the BB PCB and, assuming all of my parts are rated to minimum 18v (all of mine are 25v minimum) be fine?


Most Electrolytics are 16v, 25v, 35v, 50v......
I only purchase 35v and 50v, The electrolytics will only be working at Idle so to speak so a 2000hr will last a lifetime in a pedal from my experiences.
Rubycon & Nichicon 105 degree are my preferred brand.

When using a 18v Charge Pump board, I like to wire 9v/18v external Toggle for on the fly switching!

Here's a Guardian OD with prototype 18v Charge pump :





						Guardian OD ( Peacekeeper )
					

A great sounding Low to Medium Drive pedal. I modded for 9v & 18v. I was hanging out for the 18v PCB Charge Pump & PedalPCB had a Proto type that would suit me as I had the optional Battery. You will see the PedalPCB Charge Pump released version has been revised & updated with reliefs to suit...



					forum.pedalpcb.com


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## sodapop808 (Jan 26, 2021)

Ok all of my caps should be fine.  But I really only need help with the diode.


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## TGP39 (Jan 26, 2021)

The schottkey is a polarity protector.  I assume you are asking this question because the repetitive peak reverse voltage is 20v in the 1n5817.  my recommendation would be to use a 1n5818 or 1n5819 instead.  Can you jumper the 1n5817? Yes, but you will lose that reverse polarity protection.


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## Chuck D. Bones (Jan 26, 2021)

sodapop808 said:


> Hi everyone
> I'm going to use one of the new charge pump boards with a brown betty.  Should I jumper the schottky 1N5817 diode (D5) on the BB PCB and, assuming all of my parts are rated to minimum 18v (all of mine are 25v minimum) be fine?



Why would you run that board on 18V?  Unless you dime the trimmer, you will not saturate the opamps at 9V.  It won't have any more gain and the max volume, which is already too much, will be slightly louder.  What you will get with a charge pump is a new noise source.  You may or may not notice the extra noise, but it will be there.


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## sodapop808 (Jan 28, 2021)

It's actually for less gain.  On the BEOD a lot of people run them at 18v to actually get headroom and less distortion.  I just it'd be cool to have the option, but maybe it won't matter that much... For what it's worth, I plan on running a pot offboard for trimmer as well... Just to have as much flexibility as possible.  It might be overkill, but that's ok.


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## Chuck D. Bones (Jan 28, 2021)

I'll say it again: 18V does not change the gain, it changes the headroom and the extra headroom only matters with extreme trimmer settings.  But try it out and see for yourself.  The Charge Pump board has provisions for a 9V/18V switch.

"...a lot of people..." talk out of their ass.  The BE-OD is intended to be a high distortion pedal.  If you buy or build one and want less distortion, then consider the possibility that you bought or built the wrong pedal.  To that end, take a look at the Friedman Small Box (Complex OD), it's a lower gain version of the BE-OD.


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## sodapop808 (Jan 29, 2021)

Ok.  I like the way you phrase it as headroom instead of gain.  That is what I was hoping to achieve, though, ultimately.  To maybe experiment with the way it stacks with other pedals.  I only thought of adding an 18v as a way of having "all the options" , as it were, and by moving the trimmer to a pot on the face of the enclosure, I'd be able to create interesting tones.  I mean, I have the board, so I figured why not?  If you think it's a waste of time, though, I won't experiment to try.  I'll just build it easy.

and as far as "bought or built the wrong pedal", I'm not sure what that means.  I might have, but that's why I'm trying to understand what it does when you run at 18v or at least make sure I'm doing it right if I do decide to experiment.  I thought we were all kinda into modding and figuring out how stuff works?    
My problem is I literally know very little and am looking to others for help when I need to understand stuff.  I'm assuming you've already experimented with this, by the way you say it's unnecessary, so I can only go with your recommendation.

My only real question, still, is about wheather the polarity protection is on the main PCB or if it's ommited and replaced by the components on the 9v/18v PCB and I believe TGP39 may have answered this for me.

So thanks everyone, for your patience!


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## Chuck D. Bones (Jan 29, 2021)

I'm all for experimenting.  It's how we learn and discover new ways to get the tone we're after.  I do it all the time.  Sometimes it works out, sometimes not.  I only publish my success stories here.  There are plenty of failures too.  I'm just trying to give you a heads-up on what I think will or won't happen.  My 2nd pedalPCB build was the Brown Betty.  After playing it, I thought it had too much gain because there was no clean setting.  I even changed some resistor values to lower the gain, but ended up changing them back.  Since then, I have built a LOT more dirt pedals and some of them are great when I want that low-gain edge of breakup sound.  If you follow the forums, particularly the Mods & Troubleshooting forums, you'll see plenty of examples of people building a pedal that does one thing and they wish it did something else.  I'm one of 'em!  That's what I mean by "building the wrong pedal."  A Tube Screamer is never gonna have that heavy metal sound you get with one of the Revv pedals or the gated sound you get from a Buzzaround.  Sometimes the quest for tone takes us down a dead-end road.  Other times, it's a revelation. In some instances it makes more sense just to bail out of one pedal design and try something completely different.  That's for you to decide. 

As for the Charge-pump PCB, it contains all the reverse polarity protection you need.  You can leave the protection diode on the main board or replace it with a jumper, either way will work. 

Good luck and feel free to ask more questions.


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## jubal81 (Jan 29, 2021)

Trust the Chuck. He knows his stuff. I'd also recommend the Complex OD for what you're looking for. I'm a big fan of that one.

I'll add that I've gone completely away from using charge pump chips. They add complexity, noise and can squeal if daisy-chained with certain other pedals. I invested in a TrueTone CS12 power supply and I've found the better option is to just use the 18V tap if I want the higher voltage. I even designed my own Klone without a charge pump 'cause I'd rather do away with those little buggers.


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