(!!!!) (Best Overall Single) CV4003=12AU7=6189 Mullard UK NOS 1978 rebranded "6189 RTC" 1981 (11.2/11.7ma) 1-2% section balance (Highest mA and Gm)

1 low noise tube) CV4003=M8136=12AU7=6189 Mullard UK box plates NOS 1978 rebranded "6189 RTC" 1981 in Mullard box (RTC=Radiotechnique, France) 11.2ma Gm=2300 11.7ma Gm=2400   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