hamptone tube mic pre

This was one of my first “proper” DIY projects, the valve (or tube) mic pre designed by Scott Hamptone and kindly made public. I built two channels with my own layout – part of the fun is turning the schematic into a physical design – and even forked out for an expensive Jensen input transformer on one side. I built this some years ago, and have rescued the pictures from the void known as google sites, used back in the day before the complex engine got going.


My vocal mic is pretty much permanently patched into this then a DIY vari-mu limiter. I can’t really give a meaningful description of how it sounds – my goal was to build something that would be good and then use it, not to obsess over whether it was “better” than say the solid state variant of the circuit, which is known as the FetBoy. There is more to be had from improving my singing than improving the preamp.


Like most of these things, it is not difficult to build if you have accumulated a bit of experience on simpler projects and you are careful. Not for beginners though – life threatening electricity etc.

In progress, the small vertical pcb is similar to the JLM Go-between, and provides phantom, pad and polarity.

diy hamptone insides

Another view, one channel completed. The green wire ensures that there is always a good connection between the faceplate and the rest of the chassis. The faceplate is not actually screwed in, it just sits in a couple of slots. Without this wire I got a lot of intermittent buzz type problems.

hamptone tube pre 3b

As specified by Scott, all the power comes from an external PSU. The heaters are DC in series.

hamptone tube pre 4b



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