Ashly Sc-50 compressors

[Wireneck]

I borrowed three Ashly Sc-50 compressors from a friend for a recent project. I liked them enough that I want to pick one or two up for myself. The only problem is that im not sure what the difference in the different versions are.
Two of his were blackface models with a red power switch (button) and a limit button.
The 3rd one was a blueface model but other than the power switch being a tad different (still a button) it was similar to his blackface models.
I found a blackface for sale but it has a toggle switch for the power and no limit button. Does anyone know what the difference in all of these versions are? They are all Sc-50's.

 

[DaveSweet]

I've got a blackface with the red power switch and (chrome) limit button - that's the newer one, the blueface is the older one. I *think* blueface is late 70's, blackface is early 80's.

But sadly, I don't know the real difference. The thing sounds great on guitars and bass, I can tell you that much! Grabbed mine for $50 on ebay and that was cash well spent!

 

[Wireneck]

Dave-

"I *think* blueface is late 70's, blackface is early 80's."

I thought it was something along these lines as well. Thats why im curious as to where the blackface with the toggle and no limit button comes into the picture.
Sadly, i think people are starting to catch on to these. My friend got his for fairly cheap and now they seem to be going for at least 100 a piece.