Vinc -Audio Pro Modified for enhanced, adjustable tube dynamics with controls on front panel. Stereo tube compressor XLR or phone in/out, -10/+4dBm switchable, Extremely accurate calibration; channel to channel is only +/- 1dB over 60dB range of operation. Also installed highest quality Behringer OT-1 output transformer. This unit has tube harmonic equalizer circuit installed, does variable 2nd harmonic adjustments. (is our shop engineering sample for variable true tube harmonic equalizer effect). #9 Excellent condition, no box, unit warrantied.