Modified with transformer, Automatic EQ compressor. This design allows deep bass and impulse response to be enhanced and less high frequency attenuation and clarity enhancement circuit. Unit has a ground modification and capacitor update for 6db noise floor improvement. This version has a 4560 op amp upgrade for line out balanced out. Mic pre amp RFI suppression capacitor. Modified with first stage tube harmonic bias control (right control) Cleaned switch with silver paste. #9 condition
Had 10dB higher gain preamp. Full audio pro rev 6 modification. Has T.H.E. tube harmonic equalizer circuit. Updated mic pre with RFI suppression. Updated tube plate volts. Updated low frequency EQ predominance. Phase corrected filter. (No loss of extreme deep bass) Has complete mod of tube vactrol auto compression and EQ at 0 dB. SN 4930. Has box. Condition #9
