Starting the amp build journey
My journey of building high-performance amplifiers started in 2015 with an AudioSector LM3875 kit. This comprised a couple of simple PCBs and a bag of components.
The “gainclone” design was something discovered by a Japanese engineer – who realised that Texs Instruments had developed a very high performance set of chips: LM3875, LM3886 and LM4780. Each, when built to exacting standards were capable of extremely high audiophile grade performance.
I opted for a dual enclosure build, isolating the 500VA transformer from the amplifier circuitry. Given the very small size – the result was a high performance 50W per channel hifi amplifier.
Sound Quality
The amp still runs today and has a beautiful clean sound. I would characterise it as slightly warm (almost tube like). It is soft sounding an never tires. Coupled with small & mid size speakers its a great setup. I have run this amp extensively with Bowers & Wilkins 685s2 and 607s3.
Lessons learnt
- The gainclone concept is very accessible and easy to build
- I have the electrical and the mechanical experience so creating a low noise, long lasting amp was not onerous
- All HW sounds different – the various texas chips actually sound different: the LM3785 is my favourite
- Care in construction is time well spent
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