The LAmpex

This unit combines the microphone preamp section of the Ampex 601 with an LA2A limiter circuit. The LA2A design closely follows the original circuit, including the UTC HA100X and UTC A-24 transformers. There are additional options, but when they are turned off the LAmpex is close to the original.
(more details)
I've used the tube based power supply from the 601 to power both circuits on this unit.

'm quite fond of this "look." I was tempted to call this model "The Diner."

The Mic preamp utilizes EF86 and 12AY7 tubes. The Mic preamp also benefits from the fine HA100X input transformer.
When the mic preamp is turned off, the unit serves as an LA2A "clone" line level compressor/limiter. For more information on the LA2A, this is a good place to start: Universal Audio

Sample recordings:

Acoustic guitar recorded through a Studio Projects C-1 mic using an external phantom power supply.
No EQ, effects, or processing except for a touch of reverb.
The LAmpex was showing about 5 to 10 dB of peak reduction on the meter and was set to "limit" mode.

I decided to keep costs down and experiment with building my own T4 optical module. I got a lot of great info and ideas from for this module. I used a Walmart night light for the electro-luminescent panel for this first experimental unit. It works great, by the way. Additional T4 modules will be high on the list, though. On the left you can just see the element sandwiched in the module. On the right is the way they come from Wally World. The element is easily removed without damage.

More pictures from the build:

I don't trust plastic. I tap the plastic and put a nut on the back for safety so it should never come loose.