Noob's first project - AMZ Muffmaster WORKS!

[lastresort]

Dragonfly's Veroboard Muffmaster: http://aronnelson.com/gallery/album18/AMZ_MUFFMASTER  (he has 2 different layouts.  this build was the larger one)

I started building the AMZ Muffmaster 5 days ago, and finally got it working tonight (it's not boxed yet).  Along the way I made a bunch of mistakes, learned a couple of things and gained some confidence that it's possible for me to build more complicated circuits..  I thought I'd share some of my errors, in hopes I might ease the pain for some other noob's first build. 

First off, I aquired the parts for the Muffmaster (and for a future Sparkleboost) from a variety of sources.  Switches and veroboard from our host Aron, SmallBear for the enclosure and a few misc items, my local electronics store for resistors/capacitors and transistors, and radio shack for some emergency supplies.  Getting components locally caused some problems and was more expensive, but I was able to ask the staff questions when I was confused. 

A quick rundown:

Doublechecking my parts list before the build, I discovered. I had forgotten a 1k resistor.  A trip to Radio Shack cured this.  Except I didn't check the package in the 1K section, and accidently brought home 2K resistors.  I had to make 3 trips to buy parts and delay the start of my building by a day because of this.

I cut the veroboard so the strips were parallel to the short side, instead of the long side.  Oops.  I used the bad piece to practice some soldering.

No major problems soldering the components on the board.  I taped an alligator clip to a heavy box and used it to hold the board.  It didn't work as well for the jacks/switches.  Next build I will definitely want a better solution.  It took me a couple of hours each on two nights to get the entire circuit put together.

I take the circuit over to my amp to test it.  But I can't plug it in BECAUSE I BOUGHT THE WRONG SIZE JACKS.  Crap!  It's friday night, and my only option for building on the weekend is another Radio Shack run and a package of 1/4 stereo jacks (which I check 3 times at the counter to make sure I have the right ones). 

After replacing the jacks, I hook it up to test.  No sound.  Loud Hum. 

I read R.G. Keen's Guitar Effects Debugging Page and it tells me this is probably a ground wire issue.  Sure enough, I have a ground wire in the wrong place.  I want to change out the entire wire for some reason, but my desoldering skills suck.  The strip gets overheated and scorches on the end.  Fortunately,  the rest of the strip is still good, and I use a different placement for the ground wire.

The hum is gone, but still no sound.  I correct a bad solder found doing continuity checking with the multimeter.  Still no sound.

I can't find any other problems with the wiring, so I take drawing back to check against the layout.  On the input jack, I have swapped the tip and the ring.  I fix the drawing and the wiring.  Still no sound.

I try to check continuity across the circuit and voltages but I don't quite understand what I'm doing and nothing seems to make sense.  I think about bagging this one up and starting the Sparkleboost.  I abandon that idea quickly and go do some other things.  The next day I start reading about the switch, because it is the source of my biggest confusion at the moment.  I *finally* realize that just because my switch has a long side, and the switch in the drawing has a long side, does not mean those pin along the side are the same ones.  A quick check with the mulimeter tells me they are not.  I don't attempt to desolder. I cut the switch out and get the one intended for the Sparkleboost.

Still no sound.  I work on the continuity and voltages, it's making a little more sense.  Then I stop getting voltages as the lead for one of my probes has broken and the housing is inaccessible.  I'd like an alligator clip option for the probe, but I don't have any.  I shelve the project. 

I decided to take a look at how the jacks work, because I have used a non-standard stereo jack for output.  Again, I find I have made an assumption (a correct one) without understanding, that the post to ties to the switch for input, should be the post that ties the switch to the output (i.e. the tip post, i now know).    In my drawing earlier I had transposed the ring and tip posts on the input drawing.  But the output drawing was for a mono switch.  Since there was no change to the drawing, I didn't think to change the wiring on the output jack, and I was still tied to the ring post.

Boom.  Muffmaster works.  Sounds good too!  How great is that?

[d95err]

Exellent report! I see a lot of similarities to my first build

Good luck with future builds!

[burnt fingers]

Man if I only made three trips to that foresaken hole in the wall they call Radio Shack.  I guess I feel better about my failures ( i mean successes...um i think.)  You got it working and tha's a great thing. 

Scott

[Connoisseur of Distortion]

ahhhh, i remember my first build. It was a bunch of leads bunched together nastily with slathered solder.

didn't look even remotely like the build was supposed to.

didn't work, either 

[gaussmarkov]

i agree:  super report.  and, of course, it is great to hear that you succeeded.  nice work!

[d95err]

Some very simple tips on how to reduce the number of trips to the local Electronics store:

Combine two resistors or caps to make up a value you don't have. E.g. Two 2k resistors in paralell makes a 1k resistor. If the layout is tight, you can solder the first component as usual and the second onto the leads of the first.

Learn when you can safely replace a component with one of a similar value. Some examples are:

* Filter caps (usually a large electrolytic with the negative side to ground) - replace with any bigger value.
* Output caps - can usually be replaced with a bigger value
* Small caps - if the cap is only a few pF, it is typically used to filter out noice or to stabilize something. Can usually be replaced with a similar value.
* ...