Leaderboard

Hi Eric I'm little stuck to fund a full 8 fader pack right now...(I have a desk for sell if interested ) I have two TKD fader loaded and it work great, I still have one issue, I reduce the problem a lot, I have to decide if I can keep it this way I made few little mistake in the layout that require a rev 2 board for motor driver and I/O board. Main error was a buffer amp wired as inverter in place of non inverting, and some footprint error like wima filter capacitor with 2.5 in place of 5mm. I just cut trace and rework PCB for now, anyway, it need correction at KiCad schem and layout for a realease The real issue I just talk about, is voltage drop at the 5v rail with all led ON, I also use it for servo without local regulation. It just corrupt the AD side stability of the system, by changing the reference voltage, introducing comparator error and fader move. Initial layout put this error in the mm range, completely unacceptable. I was able to reduce this in non perceptible range by // 5Vtrace with 0.25mm2 wire and connect the SMPS sens at I/O board (prevously 3m away at the 19" rack with the core). Now I'm in the 10mV drop range which still enough to introduce jitter at 12Bit AD and of course error at analogue comparator. As I say it's non perceptible, at worst 2 step<=>0.2mm (7 led ON), and this "jitter" will always be the same. I mean for example in read mode the green LED will always light on, introducing exactly the same error for each pass, without relative difference. The worst is with mute function which light a red LED and an optocoupler, but If I mute I don't care the fader move 1/10mm So here it is: Do I keep it like this, not so smart design, with my subjective knowledge saying "it's not the best possible", when objective observation show it's just out of human perception. Or do I push a little more further and add local regulation, which will implies deeper modification. I still have 5V layout modification to made, not easy to change the "basic" when all complexity around is done, maybe I have to go for 4layer pcb! I don't see to just add 5V wire jumpers a very professional design. There is few option and I have to make the right choices to avoid V3 to soon... Last important thing for the system is the the data mapping at soft side, also OSC, but that's another topic. I have few call at groupDIY, I wish I can release this. For info, I/O board is 250x85mm, not more than 30cm cable/ribbon from the fader/motor board. Motor board is 34x120mm as close as possible to the fader, and remote is 16x150mm as close as possible to the front panel :) Best Zam