Meridian 563 DAC

I have a Meridian 563 DAC I bought used and I was wondering when this particular model was produced. Also is this a 20 bit.
I'm not exactly sure when it was introduced, but it was reviewed in Stereophile in April, 1994. I'm not sure when it was replaced by the 566.
I have one. Although you didn't ask, I'll throw my 2 cents in about this dac anyway - it's excellent, but if you ever have $700 to put towards an upgrade, get the 24-bit upgrade from Meridian (if it's still available). It brings it up to "unbelievably fantastic!". I did it about a year and a half ago, and it's worth every penny.