my distortion isn't distortioning

Started by geckomafia, December 31, 2012, 12:01:40 AM

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geckomafia

Hi, I'm Jon, a new guitar player and even newer stomp box builder. I'll try to find an introduction thread shortly.
So I decided I'd try my hand at building my first pedal. I found tonefiend's DIY section, ordered the parts for projects 1-3 plus a breadboard kit. It all came in a couple days ago, and yesterday I setup my breadboard, soldered my jacks etc., and followed section 1 of project 1.
http://www.tonefiend.com//wp-content/uploads/DIY-Club-Project-1-Part-14-v03.pdf
After I finished I was ready to make my ears bleed with massive amounts of distortion! Instead, all I heard was major buzzing with no guitar sound. After quadruple triple checking my connections, I got frustrated and went to bed. Tonight with the house to myself, after a little gee tar practice, I decided to tackle it again. First, I found that I made the ultimate rookie mistake, and reversed the polarity on my jacks .... once that was fixed, I began with the troubleshooting guide. This revealed that my negative lead on the 9V pigtail was broken (I'm on a roll folks). With at fixed, I no longer get any buzz, and I'm getting sound from the guitar through the amp.
The problem is, instead of distortion, I seem to have the opposite. It seems as if my volume Is slightly reduced and clean instead of amplified/distorted. The voltage checks are as follows. (negative lead on sleeve of input jack) Q1 is 2N3904
Battery = 9V fresh from package
R1 at collector of Q1 = 8V
R1 at base of Q1 = 3V
R2 at battery = 9V
R2 at collector of Q1 = 8V
R3 at emitter of Q1 = 7V
R3 at ground = null
Q1
C = 8V
B = 3V
E = 7V
I tried to attach a pic, but can't figure out how on iPad.
C1 at input = null
C1 at Q1 base = 3V
C2 at Q1 collector = 8V
C2 at output = null

WaveshapeIllusions

Base/Emitter shouldn't be that far apart. There should be about 0.7 V between the two. With the collecter/emitter voltages so close I think the transistor could have shorted? Transistors generally don't like reverse voltages so it could have fried with the power leads reversed.

R O Tiree

OK, there's something wrong in what you've done but, without a pic, it's a little difficult to decide precisely what it is. My advice is to rip it all out of the breadboard and start again from scratch. Make absolutely no assumptions about what you did before. Try to place the parts exactly as shown in the tutorial you linked to. Check the values of the parts with your multi-meter before placing them. Make sure that the legs of the components don't touch others that they shouldn't - that's one of the hardest things to achieve with breadboarding.

Here are the rings that you should see on the 3 resistors. There are 2 arrangements that you'll find "in the wild"... 4-band and 5-band. The 4-band ones have a gold or a silver band to denote 5% and 10% tolerance respectively. The 3 other coloured bands denote the value. The 5-band ones are tighter tolerance and the most common one found is a brown band, meaning 1% tolerance. This can lead to problems with any value starting with a "1", as they can be read either way and end up with 2 different values... take brown/red/black/black/brown, for example... read it the way I just typed it and this would be 120 ohms. Turn the resistor over and read it the other way (brown/black/black/red/brown) and it comes out at 10k! It is important that if you have 5-band resistors in your kit that you take the time to measure them with your multi-meter if you are unsure about the coding system or if you have a brown ring at each end. If the resistors in your kit are 4-band ones, then use the first code that I've shown below. If they are 5-band, use the second code.

R1 should be 2.2M (red/red/green/gold or red/red/black/yellow/brown)
R2 should be 68k (blue/grey/orange/gold or blue/grey/black/red/brown)
R3 should be 470 (yellow/purple/brown/gold or yellow/purple/black/black/brown)

The 2 caps are 100nF. The tutorial shows you the various code systems with which they can be marked. Let us know what yours say and we'll be able to tell if you got the right ones in there.

Hope this gets running...

...you fritter and waste the hours in an off-hand way...

geckomafia

Holy mis-packaged resistors Batman! This morning, I compared the bands to the above post and found that R3 didn't match. Took a trip to the local shack to pick up a couple 470 ohm resistors and a couple transistors (just in case) plus a new digital meter .... my old one was crap. Got back home, checked the value of R3 and found it to be .470 Mohm. hmmm I wonder where the problem might be?  ???swapped it with a known 470 ohm and guess what? ..... My distortionimicator distortionates now!!  ;D WOOHOO!!! Thanks for the help folks. now where is that bookmark button?  :icon_lol:

R O Tiree

Excellent news. Glad I could help. Time to move on to Part 2, then :D
...you fritter and waste the hours in an off-hand way...