Oleg,
the frequency response of the AF amplifier chain is modified to some extend by a small value for C22. But due to the excellent AF filter, low noise AF OP Amps and a lot of AF gain, I did not find this to be a problem. For my ears, the receiver still sounds superb.
You may, of course, use larger values for C22. Wheather the QSK noise is then still acceptable I did not check.
73, Wolfgang DK4RW
