It's New Years Eve and time for the last layout of 2019 and I'm pretty sure it's the 800th on the blog! So here's the Mostortion. Why is it called that? The CA3260E opamp at it's core is MOSFET based. Unfortunately, this chip has been discontinued, so building a straight clone may be a little difficult, but a regular dual opamp like a JRC4558 or TL072 will work just fine as well. It's pretty similar to a TS10, just with a MOSFET chip and 3-band EQ, which is pretty handy. Schematic and more info here. Should be able to squeeze it into a 1590B.