A beginner Needs help builing MXR distortion plus.

[Izzy]

I returned the Radioshack multimeter today. and I bought another one from Microcenter for $25 .
I think this one has Connectivity, capacitor measuring and also temperature. So I think this should be Fine.

I saw driller at Marc's for $15. It was like whole box with other stuff. Probably I will get it soon for my anotehr project.


GibsonGM dont think I ignored your suggestion, I highly appreciate it  but I decided I will go with TIN for this MXR project as this is not my type of pedal. I wont be using it much. Or may be I will sell it on ebay .
The main reason I started this project was I really wanted to learn how to build effects and understand what each part does to the signal. But before that I really wanted to build one to see how things work (I have a bad habbit of going backwards.). I was not expecting this one to work but fortunately it did. Surprise! 
Thanks to all the members that helped me so far. You guys Rock.!

I will spent some time on this mxr and try to learn and trouble shoot. In a mean time I will try to get ready for my next project Ibanez Tube screamer TS9 (This is my type of pedal  ). I will do as gibsonGM said. I will buy metal enclosure and drill it..!!haha
I have been using Tube screamer from Boss GT6 and Digitech GNX2 before . I absolutely love the tone!



Anyway, I have one question. Can I use this MXR distortion plus through Boss GT6? or in the effect chain of GT6 by using Send Return?
One of my freid told me that its not good Idea to do it because he said if DC current  goes to boss GT6 circuit from this MXR it might DAMAGE BOss GT6?? Is that true?
If yes how?

[Meanderthal]

Can I use this MXR distortion plus through Boss GT6? or in the effect chain of GT6 by using Send Return?

yes, yes

One of my freid told me that its not good Idea to do it because he said if DC current  goes to boss GT6 circuit from this MXR it might DAMAGE BOss GT6?? Is that true?

No, you shouldn't have a problem with dc current unless you have some kind of horrible dc offset, and even then the damage would most likely be to your ears and nerves(and possibly speakers) and not another effects unit. Most of us try all kinds of stuff in effects chains and loops, until we arrive at an arrangement and order that works for us. I've found that putting a distortion in front of certain effects can really bring them to life.

[Fret Wire]

1. For absolute authenticity, a 1meg reverse-log pot is needed.

500KC (rev log) for Dist. and 50KA (log) for volume are the absolute, authentic, original MXR values for this ckt.

[GibsonGM]

Hey , glad you're learning so much, Izzy!  Definitely a good pedal to play with, it's good to shop around to get the sound you want  Mine is customized to what I like, and I also use a Big Muff, Fuzz Face made with 60's Ge transistors, and an overdrive.  Where are you from, man?  I live in the state of Maine, USA.   Some of your posts suggest to me  you might be from another country (?)

To protect against any unlikely DC present on the output, measure for DC with your meter on the cable going to the amp, with effect on, before plugging it into the amp...I've actually had a breadboarded ckt with 9VDC on it!  Didn't sound too nice, LOL!

[Izzy]

hello again, I just soldered the circuit and now its not working!
I knew it!

I wanted to make audio probe but I dont have .1uf Caps now. I only have .047uf, Can I use it?
I am worried I think I damaged some component by extra solder heat may be? ?? ?

I had taken care of IC. Beside IC i did normal soldering to other component.
What could be the problem?

[GibsonGM]

Part II   
Almost any cap'll do for the audio probe, Izzy. What it is doing in the probe is making sure that if you touch a live wire in the ckt it won't transfer the 9vDC or whatever to your amp (use on low voltage and low volume only, please, LOL).  Use the small cap (or parallel a couple for more capacitance) for now and replace later with something larger (1uF, 10 uF...the small cap will make what you hear more treble is all).  You start by banging a note and listening to the tip of input jack, and move farther & farther into the ckt.  Where you stop hearing things is where it's messed up (generally speaking). 

For this stage, debugging, find the topic "What to do when it doesn't work"...that will get you going in the right direction!    Myself, I look for solder bridges, obvious goofy errors, check that the parts are oriented correctly, all jacks/power/pots are hooked up correctly.  If you've got the stompswitch in already, that is automatically suspected.  Next, audio probe/measure voltages at the IC.   The 741 is a tough chip, hard to kill, so it's not likely to be that unless you soldered it right to the board & overheated it.

Read the article, and re-post your findings, there is MUCH information on debugging...

[Izzy]

Thank you sir.
I had bought IC socket for IC. So 741 should be safe. I havent added DPDT switch till now.
Is there any chance  caps and resistor get damaged from over heating?


I am going to try audio probe now.

Any other suggestion will be appreciated.

[GibsonGM]

Very, very, very unlikely you'd have damaged the caps/resistors.  They're pretty heat-tolerant.  Transistors are sensitive, and IC's are too (but you have a socket, so are OK).  Enough heat and anything will die, but I doubt you'd go that far, ha ha.

Check for solder bridges.  Be sure the input/output wires go to the right tabs on the jacks.  Make sure the IC has power.  Measure voltage between ground (black probe goes there) and pin 7...you should get the voltage of the battery.  That way you know the IC is live.  Audio probe from input to output.  Easier to do this is someone strums the guitar while you probe (I use a recording of a sine wave at 440Hz that I plug right into the input; I set the CD player volume so the output is about 100mV, just like a guitar).

The problem is simple, I'm sure, and just something you'll have to search out!  The fun of DIY circuits, ha ha.   

[Izzy]

Finally AUDIO Probe Solved it!!!

I found ut that two point shown in the diagram wasnt soldered
But the signal through one of teh resistor still cant get through. I have tick marked the side of the resistor where I can hear signal, and I have crossed the point where I cant hear.

But distortion worker. Less hum than before.!

I checked it through Multimeter with Vdc at 20. The battery terminal of AC adapter shows 14 V . and all volts around IC are also 11-14v ??

[Izzy]

One more thing to Gibson GM or anyone.
I am sensing less gain than before. Is it because I replaced 2.2 k with 2.2k+2.2k = 4.4k before drive pot?
According to Schematics they have 4.7k.

[Izzy]

Finally I completed it!!!

Special thanks goes to GIBSON GM , Mark hammer, Aron , adn lots of other guys who has been a great help!!!
Thank YOuuuuuuuuuuuuuuuuuuuu


here are some pic.!


here are the pic is Izzy Ish-Tortion plus!

[Izzy]

  Where are you from, man?  I live in the state of Maine, USA.   Some of your posts suggest to me  you might be from another country (?)

Sorry Forgot to answer your question..
I am Originally from Nepal.
You might ask where's that at?
haha
Its between India and china. A land locked country. May be you have heard of Mt Everest, Buddha or A royal Macassare that took place like 3 years ago .

But now I am at cleveland, ohio. Been here for 3 years . I am a permanent resident now.

I hope that answers your question.

[Izzy]

To protect against any unlikely DC present on the output, measure for DC with your meter on the cable going to the amp, with effect on, before plugging it into the amp...I've actually had a breadboarded ckt with 9VDC on it!  Didn't sound too nice, LOL!

How do I do this? One probe at tip another at sleve? or some where else?

[GibsonGM]

Hi Izzy, Yes, I do know where Nepal is ;o) Very sad how the chinese came in!  I wish the world had done more to help...glad you are here in the U.S. now, and making neat effects! Your box looks nice, a great build!   I looked at your "cross and tick"...exactly what I'd expect (the 1M resistor is blocking the signal from going off in that direction; that branch is there to provide bias voltage to the signal only and represents a 2nd current flowing in). 
Less gain than before...hmm, not sure.  Maybe someone else knows? The resistor value (4.4K) may have something to do with it, you can lessen it if you like...it will make effect more treble as gain increases, so you should increase that .047 cap next to it to about .22uF if you do.  Playing is what it's all about!

To test a new pedal already boxed up, I just plug everything in except the amp, turn the effect on, and measure the DC voltage at the cable going to the amp...black probe to sleeve (inner part of plug), red probe on tip.  It's not a major thing, but I safety test everything I plug into my nice tube amp before I use it...

Going camping for the weekend in the morning - happy tweaking! 

[Izzy]

Oh haha, I have been using my small marshal amp from the begining to test this circuit.hehe.

But I was scared to test this into my Boss GT6.

I will do test the out put tomorrow.
By the way my adapter was showing 14 v  in multimeter in Vdc when I actually had set it to 9 v. Why is that?
And how much volt should I get when I check the output cable before I plug in my Boss gt6?

[GibsonGM]

I have a small marshall amp I test my stuff with too, ha ha...it would be OK if I blow it up, I just don't want to hurt the Fender!  If you haven't used the MXR with a good amp, expect it to sound much better when you do!    Since you will measure DC output, and not AC (such as the guitar signal would be), you should get very little DC present.  A small amount is ok; I typically get less than say .5V.  More like .1V due to cap leakage.

Home AC power fluctuates.  Actual peak can be about 170VAC and can vary during a day.  A supply transformer is working with the average RMS voltage that we call 120V.  Output can be higher or lower than the rating of the transformer unless it is a regulated supply.  Regulated supplies put out "clean power" much closer to what we really want.  Or perhaps your adapter is messed up?

A power supply is designed around a load.  So, for this particular, average expected load, it would be asked to be giving 9V.  When you use one with less than the designed load, sometimes you notice the voltage is higher than it "Should Be".  If you exceed its load rating, sometimes you get a lower voltage, too.  This won't hurt the 741 in this project; but some transistors and IC's might be sensitive to that and could be damaged some day in another project.  That's why you sometimes see LM78xx series voltage regulators in a few designs.   

I don't know for sure, but my hunch is that a good idea for this situation would be to install a few diodes (1N4xxx series to handle any current) in series with the + leg of your power supply. Each Si diode will drop .7V...you can use this property to lower voltage, 5 would take 14V back to around 10.5V.  But not really necessary with the MXR, and will have adverse affects if you go back to a battery supply and they're in the line or use a different transformer.  The 741 can handle up to 18V...your call, Izzy! I wouldn't do anything, personally, but then I don't use transformers unless absolutely necessary (don't like power needs on-stage). The Dist+ draws so little current, a battery lasts for like 8 months of regular use...