# First stripboard build plan: Em-Drive



## Grubb (Feb 5, 2021)

I was hoping to build a slightly modified clone of the Emerson Em-Drive, which I really like. I've read though that some of the stripboard layouts for this pedal are difficult to get working well despite the low parts count.

Can anyone give me advice or foresee issues with this layout? I was going to skip the PIO mojo caps and go for normal ones. Thanks in advance.


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## Grubb (Feb 6, 2021)

Here's the schematic for the Em-Drive. I feel pretty comfortable understanding it apart from the 3 objects branching out from the lower side of the transistor before reaching the ground. What do those symbols mean?

I am re-drawing this schematic in Eagle to match the stripboard layout in my first post, for learning purposes. Am I correct in thinking the 220uF capacitor in the layout should be connected between 9v and ground? As per this first attempt :


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## spi (Feb 6, 2021)

Looks like the 220 uF should be a polarized cap, so you can use the symbol that has one straight line and one curved line (with the negative side connected to ground).


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## Grubb (Feb 7, 2021)

Ditched Eagle and went to Diptrace - what a relief. I have an error when I run the ERC to do with only having a single pin in the first and last nets. Not sure how to fix it.


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## Grubb (Feb 10, 2021)

I've laid out the components I want in Diptrace, now I'm just trying to learn how they are connected. I don't yet understand the"flow" or directionality in schematics and stripboard layouts. For the board below, I have the following traces planned:

Input > Gain 3
Gain 1&2 > 100n Cap > Q1 Base > 2M Res (end 1)
Q1 Collector > 10K trimpot 2 > 100n Cap > Volume 3
9V (DC+) > 10K trimpot 3 > 2M Res (end 2) > 220 uF electro cap > Q1 Emitter > Ground
Volume 2 > Output
Volume 1 > Ground
9V (DC -) > Ground

Any critique or corrections of those traces? What have I got wrong? What am I missing? 

I'm not confident that I've used the trimpot correctly. How do I know if it's lug 3 or lug 1 that is supposed to be in the circuit in the top level of the stripboard layout? What happens to unconnected lugs on a trimpot?

I realise aspects of the board below are imitating PedalPCB, such as the 4 input pads that connect to the footswitch breakout board. That's not to plagiarise but literally because it's the only example I'm familiar with. I don't know any other way to do it!


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## Grubb (Feb 13, 2021)

Just sharing for anyone else trying to learn how to create your own PCB from a schematic. I found the Youtube videos from the Effects Layouts account to be really super helpful. Using what I learned from those videos, I developed what I think is a working schematic from the basic schematic above as well as the modified stripboard layout. I then added more to the power filter section, a footswitch LED and Current Limiting Resistor (CLR) as well as a reverse polarity protection diode. Now the schematic looks like this: 



From there, Diptrace generated the components with ratlines. I laid out a PCB that should just fit inside a 1590A and positioned and rotated the components to minimise crossed ratlines. Then I manually routed the traces, moving from the easiest, most obvious connections to the harder ones. At some point during this stage I learned about using a copper pour on the back layer to be used as a ground plane and to connect all of my ground connections. This greatly reduced the number of traces I needed on the board. Diptrace allowed me to connect the ground net to the copper pour on the back and so you will see pads that connect directly to sections of the copper pour.


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