Introduction: Tube Screamer Clone
I never really considered building my own guitar pedals. I always thought that it was best if I left it to someone else to build the tools which would build my tone.
When I first got into guitars, I played accoustic and the funny thing was that even though I had been playing for about 2 years, I still knew nothing about gutiars.
My first distortion pedal was the FAB Metal pedal. It was cheap. Thats really all I can say about it. The next pedal I got was the classic Boss DS-1. WIth the DS-1, I began to wonder about it and finally came accross a website which show me how to mod the pedal. At this point, I decided that I create my own tone and that is exactly what I will be doing in this instructable.
Step 1: Getting the Parts
I found the plans for this project at tonepad.com, the link can be found here:
I downloaded the PDF file, there are two options. The first is that you etch your own PCB or you buy a pre-printed board from them. Personally, I prefer saving a bit of money and DIYing it. If you do not have supplies or experience I suggest you find instructions about etching circuit boards first.
The method that I chose is using found here on Instructables.com. It is at this link:
I chose this because it is "reusable" (yeah, i know, I'm cheap). i won't write out the process of etching since it can be found at the link. I will however post pictures of how mine went.
I ordered all the parts from Small Bear Electronics. They are quite reasonably priced without the large shipping costs incurred from mouser. Definitely recommend.
Recently, i read an article about the parts which make up the tube screamer. There is much discussion whether certain parts are better then others. Some claim and swear that by using all NOS(New Old Stock) which means manufactured back when and never used. This is because they it will replicate the exact sound they had back then. I feel that it's great but considering that resistors are still resistors. Caps are still caps and ICs are still built the same.
Consider this, if a precision resistor does the same job as a carbon resistor, just better then why not? After all, one only benefits from less noise. (which is good...right?)
As for the ICs, i hear that people are willing to pay up $45 for a NOS JRC4558D. But consider this, if it was made on the same production line, using the same materials, with no change to the original. What difference does it make?
Then again that is IF those conditions are the same.
Caps(capacitors)...umm...go for the better ones?
which ones are better? here is a list(again with much discussion of order)
1/2.Polypropylene(Film and foil before Metallized)
For the actual audio chain stay away from ceramic and Electrolytics. These caps are still good, just not in audio.
Recently I recieved this comment from Spinergy(located on the bottom of the page) and I realized that it coved what I missed. Thanks
When it comes to caps in the signal path, if the original used electrolytics that's what I'd stick with here if you really so want to dupe the original sound. In an application like this better resistors will make no real difference. The new cleaner IC's will make a small but probably unnoticeable difference. Poly caps in place of electros is where the biggest change will occur. Electrolytic caps are the last thing you'd want in the signal path of your Hifi amp or speaker crossovers, but for something like this their inherently dirty distorted nature is a key part of the original circuit's voice. This is after all part of an instrument making music, not playback gear trying to faithfully reproduce a recording.
While using NOS parts is usually fine if they're cheap and readily available, I'd never go NOS on electrolytic caps. Unlike resistors, IC's, or film caps which are truly "solid state" and will store practically forever without degradation, electro caps are subject to chemical breakdown of the electrolytic paste which makes them tick. Their tolerance isn't great to start, and after 20-30 years their values can be all over the place. Not to mention they can just outright die from old age.
If you want a smoother sound vs. duplicating the original tone then poly caps are certainly the right choice. Electrolytic caps introduce distortion because their internal resistance vs. frequency is nonlinear making them act like a randomly adjusted graphic equalizer. The higher the frequency, the greater the distortion. Poly caps, on the other hand, are very linear and introduce essentially zero distortion.
Which to use in an effects pedal? No right or wrong, better or worse, it's all up to personal choice. They are a tuning element just like choosing your strings, pickups, etc.
Step 2: Quick Run Through of the Etching Process
Yes, I know, on the last page I said I would skip the etching but I changed my mine.
Here are the steps:
1. Cut board to the correct size and thoroughly clean it.
2. Use a method of getting the design on to the board. (I tryed this blue press N' peel. It didn't really work at all, I guess I used too much heat with the iron. I ended up using the toner transfer method and filled in blank spots with a Sharpie)
3. Etch away!
4. Clean the toner/Press N'Peel/Whatever off the board.
5. Drill holes.
6. Clean the board
Step 3: Putting the Components on to the Board
Now that the board is clean, you can start soldering the components. Make sure to double if not triple check where each component goes before soldering. This will save lots a of frustration in the long run so you don't need to de-solder parts.
As far as soldering goes, be extra careful with transistors, semiconductors and diodes; as they can be damaged by heat. I recommend that you use heat sink clips if you are new to soldering or do not have as much experience.
In the pictures, you can see that I placed the chip into a holder. What this does is it prevents the chip from being accidently damaged during soldering as well the chip can be replaced. Putting different chips in the holder a different sound to be achieved.
For a soldering, look for an iron with a lower wattage and finer tip.
Step 4: Working on the Enclosure
For this step, I took a blank enclosure drilled holes in it and painted it. This was my first time doing it and I needed to return the drill very quickly, thus the crappy drilling job. I was also focusing on the actual drilling so I did not have time to take pictures until after i finished the final coat of paint.
Pretty self explanitory, make sure that you measure the exact locations of the holes. Then take a punch and give the hole a bit of a "head start". Next, just take a metal cutting bit. Use the highest speed, a bit of oil and drill away.
Before painting, dry fit all the components to ensure that they all fit.
I didn't bother with de-burring the edges because only the component would be touching it.
1. Cleant the casing.
2. Spray primer on to the casing. It is best to use light coats and spray lots of them. Just make sure that you let the previous coat dry before spraying the next. If you do not the result will be a very thick goopy and possible runny paint job. If you do mess up on this step, you can always sand down the primer so that it is all even, the finish doesn't matter since
3. Spray the final coat in the same way the primer was applied.
Step 5: Inside the Enclosure
When wiring the board to the components, there is a guide on tonepad.com that shows you the different ways of doing it. What I did was I took a plan and then modified it so that it would work for what I needed.
I think that it is better to make sure that you just have enough wire but making sure that it is not too short. Too much wire will just cause it to look messy. Other then that measure seven times and cut once.
Step 6: Testing...
For testing double, if not triple check the connections. Make sure that everything is at it's correct polarity.
Start by plugging it in and seeing if the bypass(off position) works. Next plug it in and make sure the LED lights up, if not unplug and check again.
Really, there could be a billion things that might happen but it is up to you to figure it out, for the most part it's probably just an instruction error. or it might be a part error.
Enjoy the pedal!!!