Icom 756: Increasing the TX and RX Audio Bandwidth

Force them Rigs to accept True Voodoo!
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EA3HRU
Audio Head
Posts: 9
Joined: Wed Aug 07, 2013 2:47 am
Location: Barcelona, Spain

Post by EA3HRU » Sun Jun 10, 2018 1:38 am

Hi Gary,

I didn't keep notes on that, but by looking at the schematic of the radio I should have replaced R581, R518 and R519 by 10K, R526 by 1K and C520 by 2.2nF. I remember that I had to remove the board from the radio as the components were on the bottom side. All these on the main unit.

By the way, a few years later, in my radio, I found a design flaw causing the common-mode voltage of the TX ADC not being set properly. This caused the positive cycles of the audio wave to be hard-limited (clipping) with high-amplitude audio levels. The solution for this was simple, replace R449 (10K) on the DSP board with a 7k8 resistor. You may want to check on that too!

Any troubles, let me know.

Good luck!
Daniel.

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