JJ/Tesla ECC803s / High Gain 12AX7 - Dual Triode, Spiral Filament
The new JJ/Tesla ECC803s is a hi-gain 12AX7 that has a spiral wound filament to reduce noise and hum. The construction is different from the JJ ECC83 in that the plates are more conventional, but have a special heat dissipating fin that serves to improve efficiency and gain.