[Elecraft] K4 Receive Filter question

[RVZ]

I believe there are no crystal Roofing Filters in the standard K4 model.  Yet the manual talks about "one set of receive filters".  Please advise the type and bandwidth of these filters?  (DSP?)

>From the K4 Manual:  There are three models: the basic K4, with one set of receive filters and one analog-to-digital converter (ADC); the K4D, with a second set of receive filters and a second ADC; and the K4HD, which adds a superheterodyne front end that can be enabled as needed to provide even greater dynamic range. The superhet module uses high-performance, narrow-band crystal filters such as those used in the Elecraft K3S.  Thanks & 73, Dick- K9OM