This is a high quality receiver, a perennial favourite, and for good reason; Denons are really good value for money, they sound very good indeed, they are well made and don't give a lot of trouble. This one had a lot of noise through the speakers, especially the left channel, no signal came through, I traced it to a bad op-amp in the line/tone pre-amp circuit, spraying the op-amp with freezer spray made the op-amp behave almost normally, the noise reduced and signal could now be heard proving it was the problem...op amps going bad is not that common a problem, but I have a had a few. The BA15218 is a general purpose dual op-amp, I replaced it with a NE5532. The other problem was a resistor in the quiescent current circuit, overheated and burnt out in both channels, could have been the permanent noise from the noisy op-amp that caused it but I suspect someone had increased the quiescent current too much on purpose. I replaced the resistors and reset the idle current. The amp plays beautifully and sounds really good, these are very good amps, they also have a very good tuner section. Inputs include a phono pre-amplifier for Moving Magnet cartridges and that is also very good quality.