The basic purpose of a head amp is this:
- To use a low output MC (moving coil) cartridge with your existing MM (moving magnet) phono stage.
An MC cartridge typically has 1/10 of the signal strength of an MM. The signal from your MC pickup will be amplified by the head amp to a level that can be handled by the phono stage you already own. It does so without adjusting the RIAA curve. But why?
As it turns out, there are a number of reasons:
- Your favorite phono stage or amplifier only has MM input
- The quality of the MC input on your phono stage or amplifier isn't good enough
- A step-up transformer is too expensive
- Your current MC phono stage lacks the settings you need
- You want to try what MC cartridges are all about, without having to buy a new and expensive phono stage
The MM and MC cartridges behave quite different. The best topology for low noise with MM is not the same as that for MC. In short: MM cartridges need low current noise and MC cartridges need low voltage noise, but an amp can only have one of those. If there's one input stage on your MM/MC phono stage, you can be relatively sure that it is optimized for only one of them. Most likely moving magnet. A dedicated head amp ensures the best sound quality at all times. Now you can use your vintage amp, tube phono stage or any other MM phono stage with an MC cartridge.
If you have found the phono stage of your dreams and it only has MM input, you will need a head amp or a step-up transformer in order to use an MC cartridge. Step-up transformers range from expensive to very expensive. That's not to say that phono stages or head amps don't, but they can be had for less money. Look no further than to this site for proof of that.
If you're on the lookout for a DIY MC head amp, the Muffsy MC Head Amp is among the simplest and best options out there. And I'd wager it'll be the cheapest as well. It is extremely easy to build, can be had with both a power supply and a back panel, and does not require any drilling or enclosure modifications of any kind.
Every care is taken to ensure the very best sound quality, and to avoid all noise and distortion. It measures and sounds excellent, and you get the satisfaction of building your own hifi gear.
Stay tuned for more in-depth information about the Muffsy MC Head Amp.