The NAD C272 is a 150w per channel power amp from the early 2000’s. This is one of the later NAD amplifiers I have worked on. As with most all NAD equipment, the basic circuit is well thought through and was intended to offer very good audio quality at a reasonable price point.
In common with other NAD amps, revising some of the inevitable compromises that led to those price points, creates a tangible benefit. Additionally many of today’s components were not available when these amps were designed and built. My philosophy is to use the components that the designer would have used had they been available and had cost not been such a concern.
The C272 uses a large toroidal transformer which provides an adequate source, though I did increase the total available capacitance in the power supply. There were also some places in the circuit where it was worth increasing the available capacitance for power rail decoupling.
The 272 is common with other NAD equipment of a similar vintage employs an input buffer module. This, to me equates to a discrete component IC. Given the way it is connected I opted to leave it as is, though there a couple of caps that would probably benefit from replacement.There are signs of the NAD heritage in the design and replacing the electrolytic caps with low impedance, audio and bipolar types made a significant improvement.
The original main power supply caps all measured very well, and were the later versions, as in earlier versions of the C272 the power supply caps had proved problematic. This particular amp also had the original protection IC rather than the daughter board.
Each main channel amp board had new caps fitted as shown below.
The amp design is modular which made it relatively easy to work on, the picture below shows the completed unit, with additional main power supply caps fitted.
The customer has a Bryston set up as well, and the upgraded C272 is giving his Bryston 4B-ST a run for its money, as he states “In a nutshell the C272 compares equally well to the 4B-ST in many respects and may exceed the Bryston in some”