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December 14, 2011
Custom Page - arduinoday
about 8 years ago
ouch, it's past midnight in Colorado, and 11pm in California!
I missed the Arduino Day :-(
about 10 years ago
Thank you for your note.
It seems that our projects have some similarities.
Here is how I solved my 2 problems:
crosstalk was carried on the +12V wires, not the ground. I experimented with LC filters and found a good one. The idea is that the large cap (15mF) near each amplifier board provides for the current spikes. It is fed at a constant rate from the power supply through a L, containing the current spikes within each board
idle noise is suppressed using the "mute" signal. I control the amps with Linux boards and I use a GPIO from the CPU to control the amps mute
I started reading your website. Looks great, and I am looking forward to reading more; I'd like to stay in touch with you for future projects. This one was a quick demo, but if it catches up I will need to improve and make it a real product.
fyi, I've been using a switching PSU, salvaged from a PC, and it was OK for the amps (+12V) but not OK for the Linux boards (+5V). Too much noise. I used a separate switching PSU for the 5V, it is very clean, but now I have to be smart about tying the grounds together for the "mute" feature. Any idea or best practice?
I bought 7 kits to make a multi room, multi zone audio system.
I installed them in a big box, in the basement, next to each other.
I am having 2 problems:
crosstalk between rooms. If one module is cranked up, and another is not used, i.e. input not connected but normal gain (half way), there is some crosstalk. I use a PC power supply to power them. I think the crosstalk goes through the +12V power wires. How come? What's happening? How can I fix it?
idle buzz. When the system is not in use, the input is disconnected, but the gain is at its normal setting (half way,) there is a faint buzz on the speakers. How can I alleviate that issue, since I cannot remotely control the gain potentiometers. What about the STBY vs MUTE? What's the pro/cons?
Thanks in advance.
about 10 years ago
thank you for the "parts wish list" list!
I already have a great soldering station, but I need everything else from that kit, and it is really helpful to have a list.
No public wish lists :(