The LA 610 testing is complete,so I’m going to start planning changes to the circuitry. I feel the best course of action is to copy the old green UA610 console design.
But first I’m going to modify the compression circuit to use a T4B module, and I’m going to add link capability. The existing compressor “bypass” will become “link”. This selection disengages the LA 610 level detection circuit. Connecting a second LA 610 to the “link” jack will drive the first LA 610′s gain reduction amplifier.

Although the LA 610 mk1 uses the same gain control amplifier as some earlier versions of the LA2/LA2A, we decided to alter our friend’s LA 610′s to be a copy of the ’68 Teletronix version.

When I began this process, I noticed there wasn’t enough room inside the LA 610 to install the T4B in a vertical position. I designed a PCB with header that would mount at a right angle and use an octal plug. I removed the existing T4UA including all the mounting headers. I then installed the new right angle mount in the LA 610.

LA 610 with T4B module