http://gaussmarkov.net/wordpress guitar stompboxes and electronics Fri, 02 May 2008 04:53:15 +0000 http://backend.userland.com/rss092 en If you want to etch a PCB with a layout in Eagle then you will need to create an image like this one to transfer your design. This brief tutorial explains how to set things up so that you can use the Eagle export command. http://gaussmarkov.net/wordpress/tools/software/eagle/creating-a-pcb-image-using-export/ When building stomp boxes, slide switches have certain advantages over toggle switches. They are less expensive and more durable than toggle switches, which can easily get broken off by clumsy feet or by mishandling. But they can be trickier to fit, requiring a rectangular cavity to function correctly. Here's a ... http://gaussmarkov.net/wordpress/parts/enclosures/slide-switch-tutorial-2/ The Noomerang is a wah pedal by B Tremblay of runoffgroove.com fame. It's a variant of the Maestro Boomerang wah, which itself is a nice alternative to the usual Cry Baby clones, with some added goodies. http://gaussmarkov.net/wordpress/circuits/noomerang/ Yo. Here's a layout I did for the Hornby Skewes Zonk Machine. I used the schematic from the Fuzz central website. I put an extra pad for the .47 cap since I couldn't find a package big enough for the Xicon greenie .47. http://gaussmarkov.net/wordpress/circuits/zonk-machine/ I have various reasons for putting this one together. My interest was peaked when the Voodoo Lab Overdrive was associated recently with the Fulltone OCD. I was also looking for a relatively simple circuit with op-amps that I could use for an Eagle layout tutorial that I plan to write. ... http://gaussmarkov.net/wordpress/circuits/voodoo-lab-overdrive/ Simple negative feedback, connecting the output to the inverting input, makes an op-amp into a unity gain amplifier. In that setup, all of the output goes to the inverting input. If instead the amount of feedback is reduced, through a voltage divider, then the gain of the op-amp circuit becomes ... http://gaussmarkov.net/wordpress/parts/op-amps/op-amps-4-divided-negative-feedback/ Op-amp output hits the rails because op-amps are powerful amplifiers with gains in excess of 200,000. With a 9V single-supply, all it takes is an input voltage difference of 9V/200,000 = 45uV to hit the positive rail. Guitar outputs are around one thousand times that magnitude. So how do ... http://gaussmarkov.net/wordpress/parts/op-amps/op-amps-3-between-the-rails/ You have probably heard or seen it said that high input impedance and low output impedance are desirable properties for a circuit. Or at least something like that. ;-) Maybe it was the other way round, as in low input impedance and high output impedance? I found ... http://gaussmarkov.net/wordpress/thoughts/input-and-output-impedance/ A first step in understanding op-amps, and amplification generally, is to see that op-amps are like a water faucet that controls the water pressure in a garden hose. In the simplest setups, the faucet alternates between completely closed and wide open. As a result, the output of the op-amp is ... http://gaussmarkov.net/wordpress/parts/op-amps/op-amps-2-hitting-the-rails/ Appearance Op-amps (operational amplifiers) come in an integrated circuit, or IC. The one pictured on the right is in a form called DIP-8, which is short for dual in-line package with 8 pins. "Dual in-line" refers to two lines of pins, in this case 4 on each side. Each pin ... http://gaussmarkov.net/wordpress/parts/op-amps/op-amps-1-description/