Rare New Old Stock (NOS), Never-In-Box (NIB) 5U4GB full-wave rectifier valves from Fivre, manufactured in Italy during the 1960s. These are rugged, high-performance power rectifiers designed as a direct upgrade for the 5U4, U52, CV575, CV1071, and VU71 series.

Built for military and broadcast applications, these tubes feature a distinctive black anode plate, double “OO” getter on the side, clear top glass, and black phenolic base. Their long, straight envelope and robust internal structure ensure exceptional reliability under high-voltage stress — making them ideal for high-end tube amplifiers requiring stable, low-ripple DC supply.

Key features:

• Black rugged plate construction for superior heat dissipation
• Double “OO” getter (side-mounted) — hallmark of Fivre’s 1960s military production
• Clear top glass with no clouding or staining
• Long straight ST-shaped envelope
• Same code matching for consistent performance

Each unit is individually tested for emission and voltage regulation over original datasheet specifications. Known for their strength, longevity, and clean power delivery, these rectifiers are highly sought after by builders of premium audio equipment.

Available as matched pairs or matched quads upon request, with full documentation.

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