[rcag_ils]

I've found an Absolute Sound article on the Mosfet 120D from the 90's. I have a Delta 120 s/n 121591B, so I am assuming it's a 120B, what are the differences in the A, B, C and D versions?

[dB Cooper]

If you have a Delta series amp, it is later than the MosFet series amps. Later 1990s. MosFet was the very first series amps done with AVA circuits from the ground up. I bought a Mosfet series integrated in '84, right around the time that line was first introduced. Had a Delta series power amp in '97 or so. Delta was the "entry level" series and Omega or Transcendence (forget which) was the "premium" line. Frank can no doubt tell exactly what you have from the SN#. Those AVA amps just won't quit.

[rcag_ils]

In that article, AS referred it as Mosfet 120D, in the manufacture note, Frank said the name had been changed to Delta.

My Delta has a S/N of 121591B, I don't know what the B stands for, only can assume it's a Delta 120 B series.

Delta 120 was on Frank's 1991 catalog.

[dB Cooper]

My guess is that it was finished on 12/15/91 and probably the second unit off the line that day. The source will have better info than me (obviously).

[Lefty052347]

Mr Cooper is correct.

Regards,
Dean

[rcag_ils]

So the "B" signified the second unit on that day?

[avahifi]

Well, it certainly does not mean it was only the second best one of the day.

It means it was the second unit shipped on that day.

It is one tough little amplifier, very smooth and tube like, but but not as transparent and dynamic as our newer designs.

Frank