The smallest commercially available enclosure these old ones will fit in is a Hammond 1590XX/1790NS or equivalent knock off.
You have to give up the Dry Out jack, which I imagine few people use. There just isn't room.
There is room for a small toggle to replace the Filter slide switch, but this example had been jumped internally to the preferred setting, so I left it.
I should have taken a picture of the inside, but it helps to use a Dremel with a cutting wheel to take a corner off of the PCB, which helps it to fit all the way to one side, making room for the LED and DC jack on the other side. You can't see the DC jack in the pic, but it's on the left, near the LED.
Also, if you try this yourself, be careful of the power situation when connecting the LED.
The 40VDC supply floats with respect to ground and a bipolar 15VDC supply is created. You need to find ground and one of the 15VDC points to run the LED. You also, of course, must add an appropriately valued limiting resistor for the LED.
I also used a 3PDT footswitch and made the thing true bypass.
I know for whom this was done!
