If I have it right, you are going to develop a system to be used for 2 channel music and 5.1 channel video and have an amplification budget of $400. Under this assumption I would:
1) Determine the value of your present gear. Verify that the adcom amp is working, the condition of the pre, and condition of the HK. Due to age I would not spend much on repairs for these. Check fuses where channel is out. Make A decision to keep or sell. Need to know the value of this gear.
2) Consider sticking to a 2 or 2.1 system, and buying a used SS integrated amplifier not much more than 10 years old. I am not sure of the power requirements for the MMGs.
3) If 5.1 channels remains desirable, and the adcom amp works, purchase a used 5.1 preamp/processor and start from there.
1) Determine the value of your present gear. Verify that the adcom amp is working, the condition of the pre, and condition of the HK. Due to age I would not spend much on repairs for these. Check fuses where channel is out. Make A decision to keep or sell. Need to know the value of this gear.
2) Consider sticking to a 2 or 2.1 system, and buying a used SS integrated amplifier not much more than 10 years old. I am not sure of the power requirements for the MMGs.
3) If 5.1 channels remains desirable, and the adcom amp works, purchase a used 5.1 preamp/processor and start from there.