Effect Number Two: Designing in Three Dimensions

•June 13, 2011 • Leave a Comment

For my 2nd effect, I planned to build a Muff Fuzz. It looks like I’ll have to take a step back on this one. This is destined for a friend, how has served as my music industry consultant. My idea was to have the circuit connectorized so that we could easily swap the circuit. Also, I wanted to put it into a sleeker case than my first Fuzz effect. I now know that the beautiful Hammond 1590B enclosure can accommodate the circuitry, but not the connectorization scheme.

small box

It looks like I’ll have to hardwire the components. Luckily, this does not preclude all experimentation. The Muff Fuzz is essentially a Fuzz Face front end, with clipping diodes on the output, like an MXR Distortion+.  There are many ways to select and configure the output diodes. Soon, we may know which are the most interesting combinations.

Parting Thoughts on the DOD FX55

•June 10, 2011 • Leave a Comment

After I fixed the effect, I put it back together, finger-tight. That is, installed all of the hardware and screwed the hex nuts on finger tight. So everything was assembled, but loosely.

I inserted the FX55 in the signal path, between my guitar and amp. Instant success. But, wait I couldn’t turn it off! Actually every time I stepped on the switch, I heard a click coming out of the amp, but the  effect remained ON. Well this effect uses active switching, rather than true bypass. The schematic indicated that the case played no active role in the circuitry. The problem was one of these two choices (1) circuit noise or (2) I broke something. After tightening all of the hex nuts and screwing the case on securely everything worked fine. Note to self: this item is noise sensitive.

Get your own 5 in 1 effects PCB

•June 1, 2011 • Leave a Comment

If my guitar effects projects interests you and you’d like to build your own guitar effect, then you can get your own circuit board at Batch PCB. You can choose one of the circuits listed in the Burnout Sound schematics page, or a few others as well. For example I am presently building a Muff Fuzz circuit on the 5 in 1 PCB.

5 in 1 PCB

The PCB has both a ground and a VCC plane . There are provisions for both battery and line power and a circuit board is so much cleaner and rugged as compared to perf board construction methods. It available from Batch PCB. With shipping and handling, it’s more expensive that I’d like, but I do not set the prices.

 

DOD FX55 Guitar Distortion Effect Repair

•June 1, 2011 • 1 Comment

A good friend let me borrow a few of his commercial  fuzz effects so that I could use them to compare to my FuzzFace clone and evaluate my handiwork. One of those items was the DOD FX55. I’m not sure how to describe the sound from the FX55, but when I play with it, I wish I knew some Deep Purple tunes.

Anyhow, the output jack on the FZ55 was finicky and I offered to fix it. At this stage of my interest in guitar effects, I’m glad to get inside as many effects as I can and see how others have designed the mechanical aspects of their effects.

IMG_4400

DOD FX55 Distortion

This venerable old beast has given years of service and now it needed some service. Its problem was that the output jack has to be in an exact certain position, or it would not work. Luckily, I had a plastic replacement jack that fit into the DOD.

IMG_4401 Have a look inside

This effect was made in the USA, back in 1983. Not very pretty. That’s the defective output jack with the sky blue and black wires attached. Once the jack was unscrewed from the case, its problem was obvious. The tip contact was bent. Take a look.

jacks
Old (Red Arrow) and New (Green Arrow) Output Jacks

The red arrow points to the broken jack. Notice the twisted tip contact, as compared to the good jack (green arrow).

This effect was actually easy to service.  The PCBA is held in place by the potentiometers. The wires are long enough to move things around without stressing the wires or the components.

IMG_4406 See how the PCBA flips out for easy access.

While I was inside, I also replaced the battery connector. There’s not much to it. Used FX55s are cheap on eBay and there are a few web sites that detail circuit mods. The fix required abut $4 in parts and a few hours of my time, but I got a hands-on peek into another stomp box.

Fuzz Face

•May 6, 2011 • Leave a Comment

For my first project with the Five-In-One PCB, I built up a board as a Fuzz Face clone. Thing went smoothly during assembly. With one capacitor tweak, it worked pretty well. I added a stomp switch so that the effect is practical. The Original Fuzz Face had a volume pot and a tone control. The volume pot seems superfluous, as the effect output is a few dB lower than in the bypass position. I am curious about the tone control, so I will add that soon.

That’s a three pole, double throw switch to give true bypass and an Effect-On indicator LED. Since this a prototype, I put aside my Hammondenclosure for the time being. I followed Andrew Carrell’s lead and mounted the PCBA in a 4 x 4” electrician’s box. The electrical box is cheap, roomy, and readily available, so it’s a reasonable choice for anyone.

I’m someone who is relatively inexperienced with guitar effects. So at first, when I had the effect working, I really didn’t now I it worked correctly. Luckily I have friends. On Wednesday a package arrived with several guitar effects, on loan from my buddy Al. My first choice from this grab bag of effects was the Tweak Fuzz. This is a Seymore Duncan product that allows you to adjust the tone to match several popular styles of Fuzz. To my inexperienced ears, my FuzzFace compares favorably with the Tweak Fuzz.

The fuzz works identically with either box. With the guitar volume pot at full volume, the fuzz tone really cranks in. As you back off on the volume pot, the tone cleans up. I’ll have to work on embedding sound clips into the next post, so that you, dear reader, can listen and compare.

Arduino Guitar Effect

•May 5, 2011 • Leave a Comment

I saw an article today that combines my two current interests the Arduino microcontroller and guitar effects. Here .  Interfacing the Arduino to the guitar is a great idea. I’d expect that the Arduino has enough horsepower to do some wild signal processing. If you read the entire article on Instructables, you’ll see a few interesting links, like this, showing that several folks use the Arduino to perform signal processing.

It would be nice to have an Arduino shield that was set up to interface between the guitar & amp, while fitting in a standard stomp box. What circuit features would you like to see in a shield PCB for an Arduino-enabled guitar pedal? I’m making my list.

Working Prototype – 5 in 1 Guitar Effect, Fuzz

•April 24, 2011 • 3 Comments

Here is prototype 1. This is what we have, so far:

Full Wiring Harness

  • True bypass switch.
  • Beautiful red LED.
  • Three contact input jack, wired to conserve battery power.
  • Since this one is s a prototype, everything is connectorized. Normally this isn’t necessary; the component wires could be directly soldered to the PCBA.
  • My instincts tell me that I should twist my wires, but this doesn’t seem to be a common practice.
  • Notice that there aren’t any tone or volume controls. Yet.
  • Oops! I need one more jumper on the PCB, in the battery circuit, to bypass the line power connector.

The "completed" effect. The two jumpers are missing.

Trouble Shooting and Observations

  • I performed some rudimentary continuity checks to ensure the integrity of the PCB, component insertion, and wiring.
  • Power up, wait for smoke. No smoke.
  • Connector to output jack is wired backwards. No big deal, I just flipped the connector around and plugged it back in.
  • I’d like more identifiers & nomenclature in silkscreen. Also to my tired eyes, some things could use bigger fonts.
  • My first functional check: Effect works in bypass mode.
  • Functional Check number 2: With battery plugged in, nothing smokes.
  • Functional Check number 3 Powered up, the LED works. ON when in effect mode. OFF when bypassed or input unplugged.
  • Functional Check number 4: Strum the guitar; no sound. Failure.
  • Upon closed inspection, I see that I forgot to put a jumper at position C4.
  • Stuffed a jumper wire into C4, plugged it in and lo & behold, something fuzzy is coming out of the guitar amp. Can it be this easy?
  • LED needs to be mounted before it is plugged into connector or soldered to the board. This is not always the case, but it is necessary for the Dialight 607 series LED I chose.
  • To my ears, the guitar effect adds no noise. I’ll have to check with a meter at a later date.

Tomorrow:

1)      Solder in the C4 Jumper wire and test the effect out at a higher volume.

2)      Determine how fuzzy is fuzzy enough.

3)      Do I need volume & tone controls?