SM-70 PRO Specifications:

Frequency Response:
20Hz to 30KHz +/- 0.25 dB
THD: under 0.05%

S/N Ratio:  better than 90 dB stereo mode
                  better than 100 dB Balanced mono mode

Power Output:
Stereo Mode: 8 Ohm Load: 25 Watts  rms x 2
             4 Ohm Load: 40 Watts  rms x 2
Mono Mode:   8 Ohm Load: 80 Watts rms
             4 Ohm Load: 120 Watts rms

The SM-70 and SM-70 PRO are the only low cost amps on the market
that can be operated in True Balanced Mode when operated as a
Mono Block using the XLR Input terminal.

Minimum Load Impedence tolerated: 3 Ohm continuous 
               2 Ohm intermittent
               (Stereo or Mono Mode)

Input Impedence: 100K Ohm

Input Sensitivity: 1 Volt rms for full output.