I build a simple line-level tube pre-amp for fun (usually keep to instrument amplification
). Common cathode (12at7) with a DC coupled cathode follower (12au7). Amplification factor of around 4. I'm measuring some crosstalk between the left and right channel. I guess capacitively coupled(?) since it gets worse with higher frequencies. I'm now trying to find the origin. Less is better, I get that. But how much is considered acceptable? Currently it's around -64dB @ 2kHz and -50dB @ 10kHz below output level. I'd hate to be chasing after unrealistic figures.