WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
Building, troubleshooting and testing of these amplifiers should only be
performed by someone who is thoroughly familiar with
the safety precautions around high voltages.
I helped my friend to build a headphone Amp. The circuit is the EF86(Triode connection) + 6080 per channel. The interesting thing is that the sound has an echo effect in high frequency. Not too bad but unpredictable.
Is there anyone could tell me the reason? Thank you!