I programmed a toolbar button for Firefox for my own use, and I thought I would share it with anyone interested. It adds a small icon on your Firefox toolbar that will take you directly to the AMZ Guitar FX blog. I’ve tested it with several versions of Firefox, but you should be updated to the latest version for security purposes anyway.
Just install the button by clicking the link below, and then restart Firefox once it has been installed. You may need to position the icon on the toolbar when Firefox restarts. This is done by going to the Firefox menu selection of View/Toolbars/Customize. Find the AMZ-FX icon and drag it onto the toolbar in the position you want it to occupy… for example, next to the Home icon or down past the end of the location entry bar. Enjoy!
AMZ Firefox Tool
The Overdrive Pedal Comparinator is a fun online application that allows direct comparison of several types of overdrive pedals. You select two pedals, then load them into the app, which plays synced prerecorded mp3s of each pedal, toggling between them seamlessly.
While the pedal selection is limited at the moment, there are enough available to keep you occupied for quite some time on a cold night.
Check it out: OD pedal Comparinator
There are a number of stompboxes that do not have “pulldown resistors” on the inputs and outputs. As long as the capacitors on those connections have very low leakage, there will be no problems with popping sounds when the pedals are switched on. As shown above, the dc voltages at the circuit capacitors that interface to the outside world should be 0v because no dc is able to pass.
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This is the basic output stage of a typical wah-wah pedal. You can see that the pot that controls the bandpass frequency is connected not only to the output jack but also to the input of a buffer transistor that feeds back part of the signal to the first stage.
This will make the wah sensitive to the load that is placed on its output. It can also cause an adverse reaction with a low impedance input of the next stage, such as with a fuzzface type cicuit. The FF can break into oscillation with the frequency changing as the wah treadle is moved.
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I have a large pile of AC128 transistors that I sorted from recent bags that were purchased. These devices did not meet the specs for leakage or gain that I set for the transistors that I sell. You can have 2 of these leaky transistors for only the cost of the shipping materials and the postage. I calculated that $2.50 should cover the padded envelope, mailing label, plastic bag, print toner, Paypal fee, etc. (Postage and the envelope are $2.14 alone) (Limit 1 per person!)
If you want 2 of the leaky AC128 transistors, just hit the Paypal button below. Some of them may be suitable for fuzz or booster use, but no guarantee! Can be used for germanium buffers. Offer limited to US addresses only!
Order Free (leaky) AC128 Transistors:
SOLD OUT!
The Tillman jfet booster circuit is widely known in the DiY effects community and often recommended for certain guitar fx applications. I recently saw the circuit posted on a guitar forum and realized that it could be built on my Multi-Purpose pc board.
I’ve modified the instruction page for the pcb to show how to use it to build the Tillman. The instructions and parts list are on the site that is emailed to everyone that buys one of the boards. Ordering info:
AMZ MultiPurpose PC Board
Let me recommend this excellent paper on opamp distortion. It contains actual measurements of many chips that have been used in pedals, though it is more applicable to high-end audio applications. It’s a big file to download but if you are interested in this subject, it is well worth a look. Nice work, Samuel!
Samuel Groner’s Opamp Distortion Paper
Dragonfly (Andy) has posted another excellent pedal painting tutorial, this time on a faux granite finish. Check it out:
Dragonfly’s Painting Tutorial
The Proco Rat has become a classic pedal that has a legion of fans among guitar players. I have 3 of them, two Rat2 and a Turbo Rat.
The Rat is designed to have a large amount of gain and a significant treble boost. This is part of what gives it a characteristic sound, but also makes some players dislike the tone it produces.
The resistors R6 and R7 along with the capacitors C7 and C6, are the main determining factors for the low frequency rolloff.
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Make Magazine Issue 15 features DIY music projects and circuit mod information. There’s plenty of interesting info in this issue, including an article about stompboxes. They even mention me by name a couple of times 
