Guitar FX Development Board

[Macro_Ninjaneer]

I'm interested in gauging interest in my FX development board.

I designed this board because I got annoyed with having to connect pots/jacks/switches to a breadboard along with having to build a power supply. My idea was to have all of the standard peripherals that you need to make an audio project on one pcb with a breadboard section. Not having to build/wire the power supply and off board components allows you to focus on the parts of the circuit that matter.

Here is a picture of the dev board:



Here are the features on the board:

• Two solderless breadboards
• +/- 15V power supply
• +9 V Variable power supply with a buffered 1/2V rail
• Selectable power supply or 9V battery operation
• 1/4" input and output jacks
• Power rails on breadboard can be selected by a jumper to be connected to any of the power supplies, ground, or nothing
• True bypass 3PDT switch (the switch has not been added to the board in the images yet)
• 6 potentiometers in standard values (1MA, 500KA, 100KA, 100KB, 50KA, 10KA) all of which can be connected to the breadboard with jumper wires

Each of the breadboards are the standard 0.1" pitch. There are jumpers on the right side of the breadboards that allow you to connect the power rails to +15,-15,+9,1/2 rail, ground or nothing. Here is an image of the jumpers next to the power rails:



Getting power onto your circuit is really easy as you can decide what rails have what power. The 1/2V rail is tied to the 9V supply so you already have the 1/2V rail for single supply circuits available. In addition, the 9 volt supply has a potentiometer to set it to whatever voltage you would like from 1.25 volts up to 9V so you can simulate sagging power supplies and dying batteries. The 1/2V rail will track the 9V supply whatever you set it as.

The board is powered by a 16VAC wall wart. Each of the 15V supplies can source ~200mA and are polyfused so they are protected from shorts. I have run the +15V and -15V shorted together for 8 hours straight with no issues. The board recovered immediately after removing the short.

 

The main goal with this board was to make designing audio projects easier. Although it is geared towards designing guitar pedals, there is no reason why this board cannot be used for hifi audio, preamps, or synthesizers.

Here is an image of my most recent pedal which was a tubescreamer style drive:



In addition to the board I have been designing a case that can fit over the board. The idea for the case is to be able to move the dev board to the floor and be able to play with it in front of your amp while having access to the stomp switch and the pots.

The whole project is open source and you can see all of the design files up at the macrofab github here: https://github.com/MacroFab/Guitar-FX-Development-Board

Since we manufacture PCB assemblies here at macrofab (www.macrofab.com), we are considering making these available soon. I wanted to see if anyone would be interested in the board.

Thanks for checking it out!

-Macro_Ninjaneer

[LightSoundGeometry]

I would like one,

[Bill Mountain]

This is super cool.  It would really only come down to cost for me.

I have a breadboard setup that isn't as sleek but works for me.  I'd only upgrade based on if I could afford it and the number of projects I'm planning in the near future.

But regardless.  This is super cool.

Add a few dual triode sockets and a nixie supply and it'll sell like gangbusters.

[Kevin Mitchell]

It's so beautiful 

Great job setting this one up! The only issue I would have would be with the fixed value pots. Would be better to have a "breadboard" section to simply plug those style pots into.

Looks like I have another project on the mind...

[R.G.]

Looks very complete for someone who has a lot of need of all the options.

I did this in 1998:

It has almost as many options as this board, and could be amplified into more by mounting two breadboards, an L bracket, and a power widgie on a slab of plywood or particle board.

Just a thought for people who are low on cash.

[Macro_Ninjaneer]

The only issue I would have would be with the fixed value pots. Would be better to have a "breadboard" section to simply plug those style pots into.

In the first revision of the board this is actually what I did. In the potentiometer section I had 6 locations for pots to literally plug into the board. You could have any value and plug it in any slot. although this solution was nice the added cost of a second PCB and the labor to fix it was a bit more so we decided to go with fixed pots. I can post pictures of the first revision if you want to see it.

I chose the pot values by grabbing the schematics of about 20 popular pedals and seeing what values they had in common. These 6 values were used the most so that is what I went with.

[karbomusic]

Very nice...

I actually have something extremely similar which includes a suite of software and USB connection to my computer for scopes/meters etc. it's indispensable to me so you idea is a great one:



https://reference.digilentinc.com/electronics_explorer:electronics_explorer

Oscilloscope

• 4 channels, 40MSa/sec sampling frequency
• 70MHz analog input stage bandwidth
• 9MΩ /10pF input impedance
• +/-20V input range
• AC/DC coupling
• 10 bits Analog to Digital converter
• 0.8mV to 40mV/LSB resolution
• Input protection up to +-200V
• Up to 16KSa buffer depth
• Advanced triggering(edge, pulse, transition types and
hysteresis, holdoff parameters)
• Channels filtering: average, decimate, min/max
• FFT, XY, and Histogram functions
• Recording and audio functions
• Advanced data measurements for each channel and global
measurements
• Export data and waveform options

Arbitrary waveform generator

• 2 channels, 40MSa/sec
• 4 MHz bandwidth
• 10V amplitude with +/-10 V offset
• Open loop impedance 35Ω
• 14 bits Digital to Analog converter
• Standard and user defined waveforms
• 2KSa buffer depth for carrier and up to 32KSa buffer depth for
the modulator signal
• AM/FM modulation with frequencies of up to 4MHz
• Swept and damped waveforms
• Import data options

Power supplies and voltmeters

• V+ and V- programmable voltage/current supplies of up to
+/-9V and up to 1.5 A
• fixed 5V/3.3V supply with up to 2 A
• 4 voltmeters with +/-10V inputs
• Input impedance 1.2MΩ
• Voltmeter input protection up to +-200V
• Two reference voltages with +/-10V
• Auto scale and plot functions for each supply(voltage, current
and power) and voltmeter
• Save data and waveform options
Logic Analyzer
• 32 digital pins
(shared with Digital Signal Generator and Static I/O)
• 100MSa/sec
• Internal/External clock
• Up to 16KSa per pin buffer depth
• Trigger options
• Save signals values option
• Customized visualization for each signal or bus
• Tabular data visualization

Digital signal generator

• 100MSa/sec
• 32 digital pins (shared with Logic Analyzer and Static I/O)
• Algorithmic pattern generator (no memory buffers used)
• Custom pattern editor in up to 16KSa per pin buffer depth
• Import data from files options
• Customized visualization for each signal or bus
• Tabular data visualization for custom signal types only

Static I/O

• 32 digital pins
(shared with Logic Analyzer and Digital Signal Generator)
• PC-based virtual I/O devices including push buttons, LEDs,
switches, seven segments displays, sliders, progress bars
• Customized visualization

General

• Large breadboard for design implementation
• High-speed USB2 interface for fast data transfer
• 4 external trigger sources (used by any instrument)
• Possibility to reallocate resources according to the user needs
• External Power Supply DC 12V 2A

For pots, I ended up soldering pins on the end of 20 or so different values and just plug them directly into the board as needed.

[LightSoundGeometry]

oh wowo..thats what I want! that is the test equipment I have been seeking !




Digilent
Electronics Explorer: All-in-one USB Oscilloscope, Multimeter & Workstation
$659.00

this is my home made jig, a lot better than the days with the hammer on desk haha

[bluesdevil]

This is what I use as well. Except I installed a power jack along with the battery option. Simple and cheap, but hard to beat!

Looks very complete for someone who has a lot of need of all the options.

I did this in 1998:

It has almost as many options as this board, and could be amplified into more by mounting two breadboards, an L bracket, and a power widgie on a slab of plywood or particle board.

Just a thought for people who are low on cash.

[karbomusic]

oh wowo..thats what I want! that is the test equipment I have been seeking !




Digilent
Electronics Explorer: All-in-one USB Oscilloscope, Multimeter & Workstation
$659.00

If you look closely at the website, you can get Electronics Explorer for less than 1/2 of that price (since you are in school; it is designed for EE students thusly a student discount). I can only say it gave me a light speed boost in productivity and learning by starting with it because I can do everything I need in a 6x8" square. Just having the AWG and 4 channel scope on the BB saved me so many hours of head scratching it paid for itself in no time via saved aggravation alone. It's hard to express the difference between building homemade audio probes etc. or simply adding two jumpers to send a test signal through a scope.



Not to take away from the OP's board though, he did a really, really nice job.

[GGBB]

Nice idea. A couple of recommendations - I hope you don't mind.

A -9V supply is probably a lot more useful than a -15V supply (maybe even more useful than +15V). The most supremely classic DIY pedal is after all the Fuzz Face, which in it's most original form is a -9V supply pedal. Ideally you'd have all the flavors +/- 9, 12, 15, 18, and maybe even 24, but minimally I'd suggest +/- 9, 18. Also, make the 1/2Vin rail tied to or available for whatever Vin is being used, not just with 9V.

Having up to six pots is fantastic, but I'd guess most of the time you'll want at least one pot that isn't included. No B10k? No C1k for the fuzz fanatics? No C taper at all for all those LFO projects? Make sockets of some sort for the six pots (so they stay in place) and let the user plug in whatever they want.

Otherwise - great project - and it looks fantastic. What is the ballpark projected sell price? I need something like this.

[Beo]

Nice job. Here's some food for thought if you're looking for add-ons:

Second set of in/out jacks, for stereo or FX Loop.
+5v for microcontroller projects.
A few momentary switches, and maybe a few on/on, on/off/on dpdt (could be slide switches or toggles)
An LED bank

[edy_wheazel]

 I was also thinking about optimising my breadboard, and after experimenting different methods and ideeas i came up with this:



Having everithing fixed to one board has it's disadvantages, it' hard to change pot's heaving only fixed values, add switches, use different PSU, etc... To cover every one of those will end up with a development board the size if your working table, and you will only use a part of those "peripherals". So, I made them interchangeble, I build those modules (3 screws and 2 screws for swithes and others, made like 4 of each), it's a quick and dirty (but efficient) solution. Also made my own connection wires (from an old computer PSU, couse I'm a cheap bastard) colour coded (it's easyer when pin 1 of the pot is always red, pin 2 always yellow, etc...) in grops of 2 or 3 together. It's also suitable for other experiments, not only pedal building. Quick, cheap and efficient.

[Rixen]

I like it, would probably add a piece of aluminium angle drilled/slotted for additional pots if I bought one.
The breadboard I use at the moment has a slotted aluminium angle so that pots can be changed by loosening the nut slightly and sliding out from the slot. Saves taking the knob off / losing nuts etc..

Julian
www.rixenpedals.com

[J0K3RX]

Macro_Ninjaneer

I like this, a lot! I hate to breadboard for pretty much all of the reasons you listed and then some... This is something I would use! I thought of creating something like this (A tricked out beavis board) a while back but just never made it to the top 10 of my "gotta get done" list.. Your over all design and layout is absolutely perfect, for me anyway!

Very interested in macrofab as well!

[smallbearelec]

Nice job! A number of designed-for-FX prototyping environments have been proposed. The Idea Board was mine:

http://smallbear-electronics.mybigcommerce.com/kit-build-an-idea-board/

I chose to keep it very simple and so make the cost of entry as low as possible. The only made-to-order pieces are the Lucite base and the brackets for the pots and switches, and those are all available separately. I'm happy to say that it has been pretty popular.

[samhay]

OP - Are the breadbords easily replaceable?

[Bill Mountain]

Nice job! A number of designed-for-FX prototyping environments have been proposed. The Idea Board was mine:

http://smallbear-electronics.mybigcommerce.com/kit-build-an-idea-board/

I chose to keep it very simple and so make the cost of entry as low as possible. The only made-to-order pieces are the Lucite base and the brackets for the pots and switches, and those are all available separately. I'm happy to say that it has been pretty popular.

Cool.  I keep seeing it in your banner but couldn't find it on the site.

[GibsonGM]

Really, really nice work, Macro!    Impressed as h@ll. 

[Macro_Ninjaneer]

OP - Are the breadbords easily replaceable?

The breadboards are soldered directly to the PCB so no they are not easily removable.