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.
Any website reference for diy Audio Research REFERENCE 2MKII Stereo Preamplifier, REFERENCE 300MKII Power Amplifier,
Manley Studio 440 and 240 Monoblock Amplifiers,Manley Neo Classic 500 Watt Monoblock