ElectroHarmix Platinum Matched Pair 6550 Audio Output Valves - Part # 6550EHPLPlatinum Matched Pair of 6550EH Audio Output Thermionic Tubes. Part No. 6550EHPL. Manufactured by Electro Harmonix. Octal base. 35Watt output per valve. The 6550EH offers excellent linearity, power handling capacity, heat dissipation. Four pillar construction and mica spacers maintain a rugged mechanical reliability. Classic tone is sustained at a prolonged, high output. New leaded glass compound is utilized to maintain vacuum integrity. This is a