Sugden Amplifier Repairs

Sugden Masterclass IA-4 Integrated Amplifier

Masterclass IA-4 Integrated Amplifier Masterclass IA-4 Integrated Amplifier

This wouldn't power up, found the mains fuse blown. The bridge rectifier for one of the channels was short circuit (that could have been the reason), replaced them both as the original ones were much smaller than the replacements and got very hot in use, it is a class A amplifier. I thought it was a split DC supply when looking at the internals with two large capacitors per channel but turned out is was a capacitor coupled output amp, one was the smoothing the other the output.

Sugden A48 Stereo Integrated Amplifier

Sugden A48 Stereo Amplifier Sugden A48 Stereo Amplifier Sugden A48 Stereo Amplifier

The relay wasn't being operated, which didn't exist on the circuit diagram I had for the A48. Anyway, there were bad solder connections on the vertical board between the transformer and the capacitors. The relay contacts needed cleaning as the sound was intermittent.