B.I.Y Guitar pedal PCB's
[Boutique It Yourself]
So as I mentioned in the blog post, I got a couple of these really cool Multi purpose pedal PCB's sent by Thom at Maker.ie in Ireland to have a play around with and maybe do an Amp layout or two for. They have been developed with input and community support from the good people over at the diystompboxes.com & guitar-fx-layouts and I think they are a really awesome idea. Pre made Traces and spaces for all the essential stompbox requirements plus a generous stripboard section for building you D.I.Y circuit on. I believe these are going to be available as full kits with all the components you need and a workbook with suggested circuit schematics and layouts.
I couldn't find a breakdown of the boards anywhere as the guys at maker.ie are still in the prototyping and testing phase (there have been several tweaks and improvements since I started writing this) so I decided to go through the board with a multi meter and check what connects to what so I have a cleat picture in my mind of how it all links together. A lot of really clever design work gone into linking all the areas of the board with hidden PCB traces and I wan't to fully understand how all the blocks join together in order to work out the best way to use it and possibly modify it to work better for an amp circuit. Am thinking of maybe using the foot switch as a channel switch or boost switch instead of a bypass if possible
You can learn more here ....www.maker.ie/guitar-pedal.html
So first thing I realised is there is no space for a battery. Which is totally fine and completely understandable but as someone who doesn't own a pedal board, loathes wires and buy's 9v batteries by the box load, I couldn't help immediately trying to work out a way getting a battery in there. It's totally pointless and would render about 2/3's of the boards usable space ...... unusable but I'm probably going to try and do it anyway at some point but we'll put that to on e side for now
There is space on the board for everything you would need in any standard stompbox. A 2.1mm Centre Negative DC Jack. Spaces allocated for four board mounted mini Potentiometers (the pads could also be used to mount switches). A Switched on/off Stereo input jack and a standard mono output jack. A 3PDT Foot switch and Space in the top right corner for a board mounted LED + resistor combo. In the same corner is also space for a Power filter cap and Reverse polarity protection Diode . In the right corner there is space for a Transistor and a couple of caps which I assume is for a voltage regulator although I have never used one before. Another really nice touch is the voltage divider to the left of the footswitch giving you a dedicated 1/2 Vcc Rail for biasing op amps.
So I used my multimeter for about the only thing I know how to use a multimeter for and that's making a beepy noise when 2 things are connected. Here is what I found.
Power goes in at the positive pad for the Centre Neg DC jack and is Joined directly to all the parts highlighted in Red on the Schematic. The ground pad is connected only the middle pin of the Stereo input jack which is then connected to the rest of the Ground points highlighted in blue Via the Signal ground pin on the same jack socket when a guitar lead is plugged in. Thus giving you a standard switched on/off input jack set up
The pot mounting pads are connected directly through hidden traces under the board to another set of pads directly above the Stripboard section which is really nice and neat idea that reduces the need for multi coloured wire spaghetti messing up your board and getting in the way. The LED is connected through Current limiting resistor to the footswitch on the ground side. And the Signal for the circuit is either directed from the In and out Jacks to either the Send & Return pads conveniently located to the top left and right of the Stripboard section or bypassed through the Jumper marked in yellow on the footswitch giving you True bypass.
Here's what it looks like all together.
There is also some other cool stuff going on with with the power and ground rails which can be cut to give separate power supplies I think but the page has changed since I was looking at it last night so I can't link to it at the mo.
So with the board analysed I thought I best do what I was sent them for in the first place and have a go at doing and amp layout for one. I can't see anyway at the minute to modify the way the foot switch works to better suit an amp circuit without using a off board wiring and bypassing some of the clever hidden connections and thus completely negating the whole point of the boards.
- Need to Draw Electolyte Caps bigger - They are physically bigger in reality (1uf /2.2uf/47uf) all basically the same physical size. More space for Text label : )
- Need to Change Resistor design. and add value of part in Text on wider colour bands as some people have problems with colour perception
- Pot Values - Haven't specified the Pot values just yet as I wasn't able to get hold of the values I would normally use in the 9mm versions that fit on the board so just want to check that the values have gone for work satisfactorily before I go recommending them to anyone else (values chosen are 500k Linear - drive pot / 1k linear - 386 Gain / 1k Linear output volume (could use 1k resistor to half pot value)
- Have to be careful running lengths of bare resistor and capacitor leads over the top of the board due to the strip board tracks running across the top and not the underside like normal veroboard. Better to use track breaks and jumpers to cover the distance although that leads to more complex layout (A layout sticker over the top of the board would cover the tracks or could use shielding from solid core wire slid over legs)
- Circuit really noisy with DC adaptor - not how much this will improve when board is in a grounded metal box but may need to look into ways of reducing the DC hum when using
- Foot switch is off centre to bui
- Add Bright switch
- Old version of the board with no voltage devider
- Double Power filter cap
Board I am using to build on is an earlier prototype version of the board which doesn't have the Voltage divider built into the bottom left hand side of the board so I ran some jumper wires under the board to recreate the voltage divider section
Still To do
- Add bright switch
- Add speaker and switch for bypass?
- Drill and etch a box
- Reducing Volume with Zobel network to reduce output Volume ( Turning the volume down to minimum isn't enough - still to loud for running directly into an amp.
- Add Speaker to top of box
- Power amp bypass switch - giving pre amp out only (same switch as speaker bypass??)
- Use in out as effects loop in/out - Add extra Guitar in jack.
Could be useful to have at the end of pedal chain as a back up amp / testing / tuning
Wireless Power adapter : )
A really useful little thing to have in your toolbox that takes less than 5 minutes to make
B.I.Y Board Layout Graphics 
Did these circuit board layout graphics for thom at Maker.ie for use in their class workbooks and kits. Here we have a layout for the Tubescreamer, 58' Tremelo and the Cave Dweller echo. You can see the full layered layouts with track breaks and component values here on the BIY boards Layout page