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karimk

Member Since: December 14, 2011

Country: United States

  • ouch, it's past midnight in Colorado, and 11pm in California! I missed the Arduino Day :-(

  • Hello Dave,

    Thank you for your note. It seems that our projects have some similarities.

    Here is how I solved my 2 problems:

    1. 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

    2. 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?

    Cheers, -karim

  • Hello,

    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:

    1. 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?

    2. 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. -k

  • hey, 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. thanks, -k

No public wish lists :(