The whole social distancing thing sucks. Everyone realizes it, but on the good side, we can take the opportunity to work on all of those projects that have been collecting dust! I’ve worked on more projects in the last couple of weeks than I did in the previous 6 months!
I am still able to mail packages to anyone in the USA. All of my pc boards and packaging material was on-hand since late last year so it has not been exposed to any external contamination. I cannot guarantee what the postal workers do with it once they have to process the package, and the best idea is to place every package that you receive on a shelf for at least 24 hours before handling or opening it. However, I still make a trip to the post office once or twice per week to send out orders.
If you order any AMZ pcb at this time, I will include a free pc board for the Electra distortion. Just note free Electra pcb in the comment section when you check out.
In a discussion about op amp fuzz pedals at DIYsompboxes, it came to light that the schematic for the EHX Muff Fuzz that had been floating around for years had a number of errors. With the help of the generous contributors on the forum, I drew a schematic from pcb pictures that were posted.
If you want this new schematic for the EHX Muff Fuzz then check out the AMZ Schematics page.
“An analog signal is one that is continuous in both amplitude and time.” †
A bucket brigade device (BBD) does not render audio continuuosly in either time or amplitude. We can take a look at the inner working of the BBD chip to see why this is true.
If you are interested in how much noise is contributed by a resistor in your circuit, then try out the new thermal noise calculator in the Lab Notebook for a quick answer. Play around with the values and you will see why noise critical applications use low impedance inputs and sometimes chill the circuit to get lower noise.
If you are a pedal builder that likes to experiment with different op amps in your Rat pedal, then you should try the NJMOP07D chip that is still available from Mouser.
The slew rate is about 40% slower than the coveted LM308 but it is a single op amp with a similar pin configuration that should be a direct drop-in, and you can quickly test the sound of it for slightly more than a dollar!
I was surprised that when I repeated the test 10 times, I could identify the 1db change with 99.65% confidence. That was on the first pass, and with a little practice, I am certain that I could do it with 100% results. However, when testing audio devices, 1db is a large change!
There are smaller decibel differences in the testing that you can try. It is an interesting test site.
