The Seventh Circle Audio CH01 is the chassis that you will need in order to case your Seventh Circle Audio build your own mic preamps. The CH01 will house up to 8 modules from Seventh Circle Audio. This will only be compatible with Seventh Circle Audio modules as I don’t believe any other company makes modules for it. While it’s a bit of a commitment to get this chassis and the power supply and wire harness that you will also need to buy with it, it’s totally worth it in the end because you’re getting a fully customizable rack. It’s also a really nice and clean design that makes it as easy as possible to build. You can choose from a variety of different preamp modules from Seventh Circle that includes Neve, Millennia, and API clones. While they mostly have preamps, they also do have a compressor module and you can choose to buy them pre-assembled if you don’t want to put them together yourself although you can save even more money by doing so. Even if you don’t it’s still quite cheap to buy the already made modules. The chassis will take up two rack spaces and I believe it has XLR connections in the back for each of the 8 spaces. The only small bummer is that it doesn’t have any meters for the preamps but you can’t expect the world here. The CH01 chassis is cheap enough on it’s own and in the end even with all of the modules you’re not going to be spending a lot of money, especially when compared to what it would cost if you went with a 500 series rack system instead. While it takes a bit more effort and time, the trade off is worth it with the Seventh Circle Audio CH01 system if you’re interested in saving a boat load of money and getting some top quality preamps of all different types.