Typical DIY Build Process

[bluewaterpig]

Hey everyone,

I'm a beginner when it comes to DIY stomp boxes from scratch. If I get a bag of parts and a labeled PCB, I'm good to go. At the point I'm at right now, I'd like to be able to build an effect just by looking at a schematic.

Is that what most of you do? I'm wondering if I'm shooting too high here for no reason or if I'm right in thinking I need to learn more.

[bluebunny]

I don't think there's any "what most of us do".  You're certainly not shooting too high.  But you might want to take smaller steps in your journey from solder-by-numbers to DAEY (do absolutely everything yourself).  And you're right in thinking you need to learn more - we all do (and we all are - all the time).  Just stick around and read lots and lots of threads in this forum.  Neglect your day job.  Neglect your family.  Have fun building and learning.   

[Kipper4]

Lol I neglected to do my share of the housework. I wouldnt reccomend it.
She let me know...............

Welcome. I would reccomend you hang around and learn more as we all do. Learning to read schematic is a great skill to have. Start small, get a good book, Electronics 101 was my first book.
learn to do your own pcb layouts, most of us use DIYLC. its free and great to use. Theres a link at the top of the page somewhere. Or just google it.
Then theres all the mechanical side, drilling and engineering boxs. Graphics for the enclosures etc
Take your time, building and learning. Have fun.
Rich


edit
As they say around here Rock it before you box it.

[smallbearelec]

I'd like to be able to build an effect just by looking at a schematic.

I think what you mean is that you'd like to be able to create a buildable board layout from a schem, make the board--either perf or PCB--and build it into a gig-worthy enclosure. It's a worthwhile goal. However, there are actually several learning curves and minefields to it. The good news is that many of us here have been through it and can offer direction and support.

I always suggest learning to breadboard first. If you can't make it work on the breadboard, you'll definitely not be able to successfully commit to solder. While you can just pick out a schem on-line and have at it, I strongly recommend starting one of the many tutorials out there that start with a vetted schematic and walk you through the process. Some of my work is in the Beginner Project section of this Forum:

http://www.diystompboxes.com/smfforum/index.php?topic=111608.0

and there's more in the How-Tos on my own site:

http://diy.smallbearelec.com/HowTos/HowTos.html

Once you are comfortable with making something work on the breadboard, I suggest building a one-stage boost or distortion on perfboard. That process will start to give you an idea of how a working circuit on the breadboard gets translated to a buildable layout. Again, you'll find a couple of my Breadboard-To-Box builds both here and in Projects at Small Bear.

As far as doing your own layout from a schematic, I have seen a lot of attempts here to do it with pencil and paper. IMO, this is a mistake. As you get further into building, learn to use a program like DIY Layout Creator. You'll find lots of examples on the Forum to learn from, and I believe there's at least one tutorial out there for it. Learning to use layout software and then actually creating a board are major steps on the learning curve, but very rewarding.

Welcome, and Happy Construction!

[duck_arse]

what ^ they all said, including "hello".

...  Neglect your day job.  Neglect your family.....

.... but breadboard them first, then neglect them.

[noh8m8]

+1 what they said except that part about drawing schematics with paper and pencil. I started with paper and pencil and IMO helped a lot with understanding the circuitry. Of course books are important too. But then again i'm in the EE engineering field =P

[smallbearelec]

+1 what they said except that part about drawing schematics with paper and pencil.

Please note that I was referring to board layouts not schems. Sure, I also scratch out a first draft of a schem with pencil and paper. But for planning a board, I always crank up the CAD programs. I typically use DIY LC to get a pattern that I'm certain will fit on perf, then re-do the pattern in EAGLE with thinner traces to get Gerber files for PCB fab.

[noh8m8]

+1 what they said except that part about drawing schematics with paper and pencil.

Please note that I was referring to board layouts not schems. Sure, I also scratch out a first draft of a schem with pencil and paper. But for planning a board, I always crank up the CAD programs. I typically use DIY LC to get a pattern that I'm certain will fit on perf, then re-do the pattern in EAGLE with thinner traces to get Gerber files for PCB fab.

Oh my bad. I too, use CAD for my board layouts.[emoji4]

[bluewaterpig]

Thanks to everybody for the great replies. From past experience, I was expecting at least one person to scold me for not properly using Google.

I think getting to know the breadboard would be a good idea. In the mean time, I'm gonna do a Tycobrahe Octave clone and I'd like to gain the experience of sourcing my own parts (aside from a ready to solder PCB that I'm getting from GeneralGuitarGadgets).

I have a parts list and the first issue I'm running into is with resistors. I can find the correct value but then there are so many different types...do I need a certain type or is it a question of paying for better quality? Here's an example...I searched for 680k in resistors on Mouser and narrowed it down to film resistors, which I think is correct. I can rule out the obvious parts that look nothing like the small axial resistors that are used in effect pedals, but still, there are metal film, thick film, thin film, etc. Then there's wattage...

Which of these would I need? http://www.mouser.com/Passive-Components/Resistors/Film-Resistors/_/N-7gz3w?P=1z0x74a&gclid=CN2qiKuHi8kCFckWHwodqgIDSA

[duck_arse]

for years and years, it was 1/4W, carbon film, 5% tolerance. these days, 1/4W metal film, 1 or 2% tolerance are as cheap as carbon, and perform better noisewise.

and if you want small, use the 1/8W-sized metal film or carbon film types. for extra mojo, added hiss and oversize, use 1/2Watt carbon composition, 5 or 10%.

pretty much any combination of the following words will do: carbon-, metal-, film: 1/2, 1/4, 1/8 Watt: 1, 2, 5, 10 % tolerance.

[Mark Hammer]

After a certain point, you will become able to simply build, install, fire it up, and enjoy it.  But prior to that point, there will be much troubleshooting required to gain liftoff.  In service of that, it's a good idea to make your layouts spacious, so you have room to stick a meter probe in here and there and see what's going on.  Some folks might suggest test points, though I suppose some others might suggest it's overkill.

Personally, I like to tin my boards, and even my pad-per-hole boards and vero, to facilitate removal and re-installation of parts and wires.  Bare copper left in the open can easily develop a tarnish that impedes effective soldering, where tinning can be reflowed.

It helps to have a little bottle of liquid rosin flux handy.

One of the often tricky parts of "the DIY process" involves planning out the location of things.  Jacks can end up shorting out against things, the space between stompswitch and chassis edge can be big enough to accommodate battery brand A but not brand B, and the location of too-tall electro caps can butt up against the bottom of pots and toggles.  There is a history here of at least 4-5 threads each year that take the form of "it worked before I boxed it up", and in many of those cases, the issue is something shorting out against something else that was too close.  So plan out where everything needs to be, and you can avoid a lot of problems.  Less trouble-shooting time and more playing time!

[smallbearelec]

From past experience, I was expecting at least one person to scold me for not properly using Google.

Naah...For one thing, this Forum is very beginner-friendly and not given to attitude. Realistically, the information universe is so vast that someone dipping into it would want help with knowing just What to type in the Search box to start.

I'm gonna do a Tycobrahe Octave clone and I'd like to gain the experience of sourcing my own parts

Yes, learning to shop is part of the DIY experience. Here is a link to my Library:

http://diy.smallbearelec.com/Library/PartsLists/PartsLists.html

Click on Octavia and you'll get an Excel sheet with a generic parts list. The SKU numbers are for my store, but the descriptions may help with shopping at Mouser or elsewhere if you prefer.

I searched for 680k in resistors on Mouser

Their catalog is an amazing resource...I buy a lot in bulk there for re-sale, including resistors. Because Mouser is an industrial distributor, the catalog needs to be enormously broad, so it can be hard to wade through for hobbyists. You are doing the right thing when asking for help with finding the right choices. Have you gotten to capacitors yet?

[bluewaterpig]

Once again, thanks so much for all the info guys. I'm spending time on every link that you've posted.

Ok so for the resistors used in pedal builds, they should be 1/4 watt metal film...got it. This would be my choice then?  http://www.mouser.com/ProductDetail/KOA-Speer/MF1-4DC6803F/?qs=sGAEpiMZZMu61qfTUdNhG0RUkTLGOdTMutx%2fZLpRv5U%3d

You are doing the right thing when asking for help with finding the right choices. Have you gotten to capacitors yet?

I haven't ordered a thing yet. I think it's a good idea for me to ask this now instead of at each point of the ordering process...

So for resistors I should go for 1/4 watt metal film...can someone list the key qualities that I need to look for in the other parts? (Capacitors, transistors and diodes...I should be good with jacks) And is there a preferred manufacturer?

[smallbearelec]

So for resistors I should go for 1/4 watt metal film...can someone list the key qualities that I need to look for in the other parts? And is there a preferred manufacturer?

Yes, KOA Speer is fine for the resistors. Xicon is Mouser's house brand and also good. The quality of even no-name generic components from major distributors tends to be good these days. Especially for capacitors, it is more a question of getting the right style and specs. Small value capacitors for pedals are most-often 50 or 100 Volt polyester film; I carry Topmay, but Panasonic, Vishay, Wima are also fine. Electrolytic types are common for larger capacitances; Nichicon is a name I know, and I buy a ton of Lelon from Mouser.

[MaxPower]

If you are building on a perf-board, you can draw the layout of the components on the perf-board in pencil. That way you can see how much space you need, and where. I find this really speeds up the building process as you don't have to keep referring to the schematic.

[PRR]

> build an effect just by looking at a schematic.

Print the schematic. Poke the part legs through the paper. Join as indicated.

It won't be minimum-size. Some parts are not as small as their symbols and you have to cheat. It may have "layout problems" (though a good schematic is often a good layout guide). It isn't very road-worthy. Hard to mount in a box. But it will work. (And does save some tennis-eye when it doesn't work and you have to compare the build to the schematic to find an error.)

> Which of these would I need?

Mouser sells resistors for EVERY purpose. 99% of their stock you would NEVER want in small electronics.

You can mess-about with electronics for decades, kinda-learn what type of parts you find in other people's work, and learn to find similar parts for your own work.

You think resistors are confusing, wait til you shop for capacitors.

Tip: stick with stores who focus on PEDALS. Bear is shy but he KNOWS what you really want and doesn't clutter his store listing with stuff you don't want. There are other pedal-parts stores. There are also guitar-amp stores but they lean to the higher-power higher-volt parts not suited to pedals. There are audiophile stores, but they have to stock a lot of exotic parts which some audiophiles think sound better for re-production. And then there is industrial, micro, military, and super-precise stuff with specs (and prices!) which are "too good" for our needs.

Until you have a good sense of what you want, shop at pedal-parts suppliers. I happen to know Small Bear's head bear, but there are several others with more or less appropriate selection and in different corners of the world.

It's like I decide to eat fish (I don't), and go to the Boston fish market. They have hundreds of kinds of fish, from $1 to $1,000 a pound, and I don't have a clue. If I go to ShopRite, they have a dozen fish, most around the same price, and this must be the fish most people really eat. If even that is overwhelming, the frozen section has two brands of the same breaded Alaskan white-fish, which is fish, and many people eat it. *After* learning my breaded/frozen, and working my way through the fish counter, *then* I may be ready to start exploring the big fish market.

[tubegeek]

I'd like to put in a plug for buying a huge resistor assortment off of eBay at some point. You'll pay almost nothing per piece and the shipping is cheap. I think the ones I bought are 1/4W which is probably even overkill for almost all pedal applications. I'll come back later and put in a link. "Metal film resistor assortment" should do it.

EDIT:

here, check this out, how can you go wrong for 8 bucks?

http://www.ebay.com/itm/64-values-1280-pcs-1ohm-10M-ohm-W-Metal-Film-Resistor-Resistors-Assortment-Kit-/321801231943

This way you'll never be stuck for some odd value and have to order it in a rush. I know the inclination is to order whatever the BOM (bill of materials) for your current project calls for, but buying in bulk will save you time and aggravation and even some money.

Plus, you'll never fill up your basement completely if you just buy individual items as needed!

In chorus with others: WELCOME!

-j

[amptramp]

We all know how projects ought to go.  Here is how the normal DIY Stompbox project usually goes in stepwise format:

1. Think of a function you would want to implement as a stompbox.  The inspiration for this can be a request from a band member, an idea that suddenly pops into your head, a dream or a sign from God in the heavens.

2. Procrastinate.  You may want to rush into the design but think about how you can do an octave up function: you can use a fullwave rectifier, an analog multiplier with the input going to both multiplier inputs or a log → 2x → antilog.  The more time you waste, the more will come to you.  Most functions have more than one implementation.

3. Draw up a schematic to implement your choice of functionality. Most CAD systems are a pain in the butt to use so I use pencil and squared paper.  This allows you to run parallel lines at different darkness and not have an array of parallel lines that you cannot follow because they are all the same darkness.

4. Do a tolerance analysis for the worst-case parameters of each device so you can determine the effect of initial tolerance, changes with temperature, changes with aging and get maximum and minimum values.  This should be a spreadsheet.  Things like bipolar transistor hfe and FET Idss and Vgs(on) go all over the place.

5. Select your derating constants so you can keep away from using up all the rating of each device.  For example, electrolytics will survive being used at their rated voltage but their life may be limited.  Choosing a 60% derating means if you are using a 50 volt capacitor, you can only use it in circuits that run at 30 volts or below.  NASA and NAVSEA deratings are popular and NAVSEA is actually more stringent.  You may decide on a 50% derating for resistors due to lack of thermal conductivity or extreme temperatures like an outdoor concert in Arizona or Alaska.

6. Perform a stress analysis that looks at each rating and determines if you are exceeding the derated values using the worst case tolerance from the tolerance analysis.  This is normally voltage, current and power for passive devices and this expands for active devices.  Every rating line in a specification should lead to a line in the analysis spreadsheet.  For a MOSFET you will have Vgs, Id, Vds, Pd and other line items from the spec.  For an op amp, you have supply voltage, power dissipation, common mode range (difficult to describe mathematically) and a whole lot of other things from the spec sheet.

7. Generate a parts list using these analyses.

8. See if you can actually obtain the parts on the list.  Some are vapourware and others were spec sheets that were floated just to see if there was any interest in the part, which never went into production.

9. Revise your parts list based on availability.

10. Order parts.

11. Wait for parts.  Or go buy them locally.

12. Design your enclosure using the same squared paper you used for the schematic.  Put the jacks, controls, switches and indicators in the position you want to see.

13. Select your connection technology – point-to-point wiring, turret board, vero, pre-patterned board, printed circuit board or whatever.  Hey, cordwood anyone?

14. Using your trusty pad of squared paper once again, lay out your circuit on the board or connection methodology of your choice.  Want to use a CAD system?  Suit yourself.

15. Revise your requirements when you find you can't fit the board into the enclosure.  In that case, get another enclosure and revise your drilling detail as necessary.

16. Select the finish you will use – paint, etch, powder coat, waterslide decal or any other.

17. Revise your artwork drawing so the control knob positions do not interfere with the art.

18. Some finishing methods require drilling first and some require drilling after finishing. Guess correctly.

19. See if the board fits in the chassis.  Oops.  Repeat the last four steps for being such a dumba$$.

20. Assemble parts on board.  Curse those that don't fit and order smaller parts or change the layout.  In some cases, this means changing the board size and the enclosure size. Oops again.

21. Assemble external wiring like jacks, indicators, pots and switches so it mounts from the inside.  If it mounts from the outside, you have to unsolder something every time you need to take the circuit out of the box.

22. Assemble the board and external components into the box.  Oops at this stage? Bummer.  Take the board out again.

23.  Connect a power supply to the power jack.  If you get it backwards, too bad for you.

24.  Switch on supply.  Check for smoke, fire or rapid overheating.  If so, fix it.  If not present, connect guitar and amp to see if you get something.  When you don't, switch connections so the guitar goes to the input and the amp line comes from the output.

25. Operate the unit in bypass.  If there is no signal, fix it.

26. Switch the effect on.  When it hums, check for ground loops, bridged solder connections or dry connections.  Fix it.

27. With the hum gone, fix the oscillation.  Keep input and output leads separated and make sure you have any necessary feedback lead capacitors in place.  Make sure you have a resistor going to the output to keep capacitive loading from causing oscillation and isolate the electronics from the big bad world out there.

28. Drop the unit on the floor while it is working.  If there is any interruption or it stops working, fix your workmanship and retest.

29. Put the unit in a toaster oven (the same one you used to cure the paint) and set for a nominal high operating temperature like 131° F / 65° C.  Operate the unit while still hot.  If it doesn't work, oops.  Reset schedule.

30. Put the unit in the refrigerator in the freezer section.  While it is still cold, operate it.  If it doesn't work, oops.  Reset schedule.  Put unit back in toaster oven to drive off moisture from condensation.  Or do what makes sense, do the cold test before the hot test so there is no separate step for driving off moisture.  Keep in mind, a Fuzz Face will always fail temperature extreme tests.

31. You now have a pedal that can be used, given to a user or shipped to a customer.  Or tossed into the pile and never looked at again.

[duck_arse]

I like to apply #28 to all parts involved, just to make sure.

[bluewaterpig]

Thanks for all the help.

I put together a cart on Mouser, though I think I'm going to go through another site after hearing some of these posts, but anyway, I tried to track down all of the resistors needed for my first project.

Just so I can get a boost of confidence here, can someone check to see if I chose the correct resistors?

Project materials: http://www.generalguitargadgets.com/pdf/ggg_toct_bom.pdf

Mouser cart image (resistors only): https://flic.kr/p/ATsdT4