DOD EQ660 (602d circuit) Schematic

October 19th, 2024: Traced the schematic for DOD EQ660 which has a 602d circuit. For those unfamiliar, the 602 is an equalizer with little to no information available aside from a picture on the infamous EFFECTS DATABASE.  However, I can only assume that it was a predecessor to the EQ660. 

As of now, I have not built this schematic, so there very well could be errors. If you end up building one and find any issues, please let me know! I apologize for the somewhat confusing schematic. I will be making a digital version of the schematic shortly. For now, please check out the video and also below for how to read the current schematic.

How to Read the Schematic

As mentioned in the video, P1 refers to the path in which each pin 1 lug from all 6 potentiometers are connected. Therefore, you will have continuity between all potentiometer pin 1 lugs. You can see the path in the photo below, which is the second from the bottom.

For 'P' with decimal (e.g., P3.3), this refers to the potentiometer number along with the lug. In the immediate photo below, this will be the third potentiometer from left, lug 3.

1A3 refers to the first, from left-to-right in the photo below), TL022CP. In the photo below, this is the left most TL022CP.

The sliding potentiometers are CTS 1979 31st week, QR6858. I'm assuming they're B curve, 100K with a 30% tolerance, but I could be wrong. If I find any information, I'll update this page.