Amp/Preamp Asylum: Re: Parasound 2200II related to Halo A21? And to JC1? by john curl

These are similar designs on paper. It is like comparing a Porsche 924 to a Porsche 968. The JC-1 is more refined, mostly by Bob Crump with passive part selection, and Carl Thompson (formerly my Vendetta business partner) who did the circuit layout. The JC-1 is a successful experiment in amp refinement. All other Parasound amps do not have this refinement. Carl Thompson just got his JC-1's this week, and he has been using a modified HCA-2200 for years. There is a real difference, but not one that can be easily measured. For the record the HCA-2200 also uses FET's to drive the bipolar output devices. The only significant difference is that the JC-1 is all FET's, except for the bipolar output devices, and the 2200 has bipolar cascode and line drivers. While these devices could be swapped out for FET's, I doubt that it would do that much.