What is the input impedance of the Classe DR-9 amp

Thanks for the input. Tech support at Classe couldn't tell me for sure, saying they thought it probably was 50-100K, similar to the responses here. I might have to resort to finding an oscilloscope and 'tuning' the crossover based on how the amp responds to input waveforms.

The input impedance that I supplied was for the RCA/unbalanced inputs.

According to a review in Stereophile vol 11 no 10 by Arnis Balgalvis, input impedance in stereo mode was 100k and in bridged mono 25k.