(!!!!) (Best Overall Quad) CV4003=12AU7=6189 Mullard UK NOS 1978 rebranded "6189 RTC" 1981 (8.8/8.8, 8.8/8.8, 8.6/8.8, 8.6/9.0mA)

1 low noise quad) CV4003=M8136=12AU7=6189 Mullard UK box plates NOS 1978 rebranded "6189 RTC" 1981 in white boxes (RTC=Radiotechnique, France) 1 section) 8.8/8.8ma Gm=2000/2000 1 section) 8.8/8.8ma Gm=2000/2100 1 section) 8.6/8.8ma Gm=2000/2100 1 section) 8.6/9.0ma Gm=2000/2100   Tested on Amplitrex Good Ma range 8-10ma Good Gm range 1800-2200 great midrange and good bass Low Noise and zero microphonics   Recommended for - Concert Fidelity CF-080LS Hybrid Line Stage Preamplifier - Ampeg SVP-PRO Bass Preamp - Velleman K4000 kit - Audio Note CD2 - ROTH AUDIO MC4 MUSIC COCOON 2009 - Eastern Electric Minimax - Hovland - Schiit Vali 2