After almost two years the SE1 mod is finished. Now intense testing can start.

Here’s a quick shot of the new inside. The aluminium back extension contains the six jack boards with all the audio signal amplifiers and CMOS switches. Those boards are connected to the analog PCB of the SE1X directly via shielded cables.
The control board for all the new circuitry resides on top of the SE1X digital and analog boards, shielded with a large copper-cladded FR4 sheet.

The new SE1X has 44 1/4″ jacks – somewhat more than the original two connectors. The meaning of the abbreviated information shown on the labels is explained on the very bottom of this page, so scroll down for a reference until I’ve finished the block diagram.