Basic Voltage-Controlled Amplifier abram, September 1, 2017September 1, 2017 I’ve been looking at the theoretical principles that govern the voltage-controlled amplifier (VCA) recently and came across some simple VCA designs that caught my attention. A common technique involves a JFET and an opamp to achieve VCA type operation by using the JFET as a voltage-controlled resistor somewhere in the… Continue Reading
DOD FX55B SupraDistortion – BigBuff Mod abram, September 16, 2014August 9, 2019 Here’s another in a line now of DOD pedal mods. For this FX55B, I decided to go for more of a BigMuff sound. Playing around with this pedal initially, I found it to be like most mass-produced distortion/fuzz effects. It had a very thin sound and that notorious volume drop… Continue Reading
TDA2040-based amp schematic with EQ… abram, June 4, 2012 well here’s the first draft of the simplest medium powered solid state design i could muster. TL082 can easily be substituted with a TL072 which is probably better anyhow (i just have all these TL082s laying around). the power supply i’m using more like 14-15V. both ICs should easily be… Continue Reading
Bending notes with PT2399… abram, November 28, 2010November 28, 2010 i’ve been experimenting with this PT2399 chip and using various schematics to create a digital delay circuit. the delay time seems to be directly attached to the sample rate since lengthening the delay time gives a nice decrease in pitch. i’m toying with the idea of dropping a time constant… Continue Reading