The Tung-Sol 12AU7, manufactured in Russia, ensures very low noise. It has been designed to mimic the performance of American NOS 6189 tubes. This one proposes an open restitution certainly audiophile, but will also work very well for the design of an amplifier guitar, this one supporting very well the distortion.
The Tung-Sol 6650 tetrode tube was developed for applications in the amplifier output stages of high fidelity bass amplifiers. It respects the construction of the original 1960 version with triple gas trap. Equivalent to KT88.