The TL074 is the most common quad operational amplifier IC in the DIY pedal world. This IC was created by Texas Instruments, who continues to make the majority of these today. These are inexpensive, low-noise OpAmps. This comes in a DIP-14 package.
|TL074 Quad OpAmp |
Download Datasheet PDF
(actual brand may vary, but we typically sell Texas Instruments in this IC)