Projects
SSL Mix Buss Compressor Clone
Progress: Complete
This project is based on the information found at Gyraf Audio. I ordered my PCBs from Swedish Chef at Audio Kitchen, and I can really recommend the service.
I bought the VCAs (THAT2180LA) and the 5532/5534 opamps as well as the moving coil meter from Farnell, and all of the other parts from my local Jaycar. In retrospect, I should have also ordered the 79L12 and 78L12 regulators from Farnell as well, because Jaycar only stocks the 78L12 - I just used regular 7812 and 7912s, not a big deal, but it was a bit of a struggle to fit them on the board. Also, the first set of pots I got from Jaycar where terrible - all scratchy, and they didn't work most of the time - I'm sure Farnell would offer better choices for these as well.
I populated the boards, and powered everything up. At first I had some trouble with the connected I had used on the control board. For some reason, I used a connector on both the main board and the control board. I just took the connector off the control board and soldered the wires directly to the board. Once I did this, and replaced the poor pots, everything worked as expected. I sent a drum mix through it, and it sounds fantastic!
I measured the gain in bypass (it still goes through the VCA), and it should be unity. It isn't quite unity, there's a 0.1dB difference, but that's close enough for me. I also measured the ratios, and they're not exact either. You can do some modifications to correct them, but as far as I'm concerned, it's all 'analog character'.
I mounted it all in a black 1U rack case I got from Altronics. That was a bit of a mission, especially cutting the hole out for the meter. I ended up doing it by marking out the rectangle I wanted to cut, and drilling as many holes as I could, and then filing it into the right shape. It worked out pretty well, I'm really pleased with the results! The only things left to do are cosmetic, get some cooler looking knobs, and labeling the controls. I'm not sure if I'll ever get around to that though, it's very functional as it is.
