Projects
Balancing Circuit
Progress: Complete
The Digidesign 001 I used to use for recording has a mix of balanced and unbalanced outputs. The monitor outputs and outputs 1 and 2 are balanced, outputs 3 to 8 are unbalanced. This was done, according to the manual, because they were reaching the limit of what the PCI bus can provide power-wise with the phantom power and balanced inputs, which is fair enough, they are important. But I hated having a mixture of balanced and unbalanced outputs. My solution to this was to build something to balance the unbalanced outputs.
This was easily done, there are some fantastic all-in-one chips from THAT Corporation designed just for doing a really good job of balancing audio signals. I found I could easily get some THAT 1646 balanced line drivers from Farnell, and the datasheet has some pretty simple circuit applications. I designed a small PCB that has 2 balancing circuits on it. It just takes signals in, as well as power supply, and provides 2 balanced outputs. There power supply will have to be built seperatly. I got a whole pile of these boards fabricated at PCB Cart and used 3 of the boards mounted in a box to balance the outputs of my 001. If you want to buy some of these boards, or want the layout or schematic (EAGLE format), just contact me.
Here are some photos of the finished product:
