Multibander

After doing the GssL 20th anniversary circuit, we decided to clean out the old, group projects from the PCB shop and see if we can come up with something new. We give you, the "Multibander". This circuit greets us with a single channel input, puts it through a 6db/oct high pass crossover for a high band, a high and low pass for a mid band, and a low pass for a low band. The signals are sent to individual outputs, so you can interface any piece of gear on each band, then carry it back to one of the returns on the Multibander, where signals are summed into a single, full band output. Essentially, you can build a multiband processing device with your existing hardware. As a practical addition, there is a bypass on each insert, as well as a solo listen function for each band. The board we layed mono (This is mostly a practical consideration to account for the total of 8 XLR board connectors, and a decision not to design for DSUB connectors). You can combine two boards for stereo, as long as youre a little strategic about bundling a few controls.

The max amount of frequencies available depends only on the switch you use. For this, we use a Lorlin 2x6 on the prototype.

The Lorlin switches are sometimes frowned upon, but we consider them excellent value, and find it easy to work with readily available parts (and still see less of them fail than more fancy options after 20 years of building and doing repairs). We will get the correct values up when we have it all checked out. Board and case layout is done - well do the (very simple) math for the filter frequencies and order in parts as our next step. I set up and shared a google sheet with a filter value calculator here https://docs.google.com/spreadsheets/d/1pasWx6WGnWoxhe4Jlv_BoIBsa7iy9zBYNAv4JKXXI0E/edit?usp=sharing You can input frequencies and a capacitor value, and it will show you the resistor values needed on E96 ladder You should not be able to edit the calculations, the E96 table, or the resistor value cells, but not 100% sure how cell protection is assigned. Let us know if anything seems off!

Boards are ordered in, and we have a few extra sets we might put up for sale. Gustav & Isak