#1
So I'm building my first pedal and wanted to share the build to UG with pics. Whoo!
I'm new with electronics so I'm just doing the standard Rat circuit found on tonepad. I already ordered all the parts and I'm currently waiting for them to ship. My friend's making the circuit board for me.

So so far I've got the design ready for the package.

I've got some red paint left from my strat project so that's what I'm planning on using. I guess it's ok to left the metal bare at some parts. Should I laquer everything in that case or just the paint parts?

So nothing interesting yet but I'll be updating you when the parts arrive ;D

EDIT: Here's the design in bigger resolution
Last edited by taatelikoira at Aug 19, 2008,
#2
looks sick! i wish i could draw....
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#5
Quote by kurtlives91
The DC jack you are using will be an issue. It is not insulated so your B+ will whort to ground. Ie. the pedal wont work.


omg why would they sell stuff like that :-o

Edit: I checked it and the plug won't connect with the stuff visible outside so it'll work. drama Drama DRAMA
Last edited by taatelikoira at Sep 1, 2008,
#7
So I soldered everything together on a breadboard but something went wrong and now I need yer halp >: (

"Why does my pedal have a horrid crackling or "gating" sound when I play? I have to hit the strings really hard to get it to make sound and it's horrible....."
<----- That's my case exactly!

When I'm playing chords/rhythm I get a distorted sound but the signal quickly dies of crackling. Soloing is impossible since the notes only sound when picked and then die off immediately - zero feedback, zero sustain.


I found this site describing a cure but my problem is I'm not a native speaker and therefore I find it hard to understand this wall of electricity related text. So what I want is someone to roughly explain what I'm to do lol.

The text says either one(or more) of the circuit's transistor(or IC) legs are biased incorrectly.
So that means that something's wrong with the one(or more) circuits leading to one of these legs = practically any circuit? ------> I'm supposed to recheck everything (I've done this several times)

Am I rite? does someone know a more specific diagnosis?

Ps. I'm getting a multimeter soon so I won't have to rely on a visual check
#8
if its a biasing issue with one of the transistors, then one of the resistors probably isnt the right value. I made a fuzz pedal recently with some good ol' germanium transistors, but they where the exact correct values, so I got a couple of 10k resistor trim pots so I could dial in the appropriate resistors...

but i'm guessing you went with some silicon transistors? those are much more accurate and I wouldn't think you would need this problem.

It could also be something like a bad or weak connection somewhere
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#11
I got the multimeter today, but I'm clueless on how to use it : (
How am I supposed to measure the voltages of the transistor legs?
What I did, I connected one end to the battery and the other to the leg and these are the values I got:

.......... __ 8,5 (that's my battery value, it's not a new one)
..........|
4,1-> |
..........|__ 8,5 --> to volume


EDIT: I remembered that the plug not being in the input jack affects the circuit so here are the "real" values:


.......... __ 8,5 (that's my battery value, it's not a new one)
..........|
1,4-> |
..........|__ 0,0 --> to volume
Last edited by taatelikoira at Sep 22, 2008,
#13
I know that pin 4 and 5 are right.
Gear:
Schecter Hellraiser Deluxe
Boss DS-1
Crate GTD65

GAS List:
Mesa Boogie Dual Rectifier Roadster
#14
One leg on ground one to probe.

For you transistors the difference between the collector and emitter should be approx one silicon diode voltage drop (0.3V - 0.6V). Measure the transistors like I mentioned and check the results.

Any spot on the op-amp that is connected right to your v-ref should be around 4.5V if your voltage divider is linear and splits the input voltage in two. I cant be bother to look up the schem.

Your op-amp voltages seem quite high, look for solder bridges. Your input and inverted output should only be a couple of volts if that.
#16
Quote by taatelikoira
Here are the transistor values:

Ground 2,67 V
Source 3,25 V
Drain 0V

OP-amp values:

1. 0,30V 8. 0,07V
2. 0,23V 7. 0V
3. 0,10V 6. 0,21V
4. 3,90V 5. 0V


Your op amp is getting **** all voltage.

Check for short circuits. See if any excess solder is touching another solder join. Also look for bad solder joins. If its dull you should try reheating the joint.
#19
OMG for some reason I measured the values with one probe on the input :S\}@£@€€€as I must have been truly fatigued... In fact the first values I posted were the right ones since the bat is connected to the ground...

So once again, here are the transistor values:

Gate 0 V (that "ground" was my bad, and it wasn't grounded btw)
Source 1,4 V
Drain 8,5V

OP-amp values:

1: 7,8V 8: 8,4V
2: 7,6V 7: 8,7V
3: 4,1V 6: 8,0V
4: 0V 5: 0V


This build seems to fail pretty hard... : (
Thanks to you people who still care to help