USA Shipments only. The only difference between 6146 and the 6146A is the type of filament. The 6146A was developed by RCA and is called a "dark heater". The two types can be mixed in use. 8298 is the same as the 6146A. Cannot be interchanged with 6146B as it has different bias requirements, inter electrode capacitances, etc. The 12 volt equivalent of the 6146 is the 6883. The 12 volt equivalent of the 6146A is the 6883A/8032 (208) 852-0830 Fax (208) 852-0833

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