I had used a pair of these in an 805 Stereo amp (now sold), and they were stable and held bias without issue. amplifier vacuum electron tube valve rectifier stereo guitar audio preamp preamplifier 805 211 FU5 FU-5 845 VT4C VT-4C VT-143 VT143.
I had used a pair of these in an 805 Stereo amp (now sold), and they were stable and held bias without issue. amplifier vacuum electron tube valve rectifier stereo guitar audio preamp preamplifier 805 211 FU5 FU-5 845 VT4C VT-4C VT-143 VT143.