[Elecraft] K3 upgrade to K3S question

[GRANT YOUNGMAN]

According to the Elecraft website, the rev C DSP board introduced the low frequency improvements that were then carried over to the rev D board.  So if you add the LPF module to a rev C (a simple addition), you have the equivalent of the rev D without the need for a board swap.

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> You can do the DSP board swap if you want both.
> But if you are only interested in the high frequency end, Elecraft provides an inexpensive kit to add the LPF to your existing DSP board. That was my choice because I was not interested in the extended low frequency response.
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Grant NQ5T
K3 #2091, KX3 #8342