Radiotron ECC803S Preamp Tube – Tests Strong – Rare Long Plate 12AX7 Variant

Up for sale is a vintage Radiotron ECC803S preamp tube that has been tested and found to be strong, with plenty of life remaining. (Radiotron was an RCA division)

The ECC803S is one of the most desirable and sought-after versions of the 12AX7 family, prized for its low-noise operation, exceptional detail, and rich harmonic character. Featuring the long-plate design associated with premium European production, the ECC803S is favored by musicians, audiophiles, and recording engineers looking for the finest vintage tube tone.

This Radiotron-branded example delivers the warm mids, smooth highs, and dimensional soundstage that have made ECC803S tubes legendary among tube enthusiasts.

Features:

• Vintage Radiotron ECC803S preamp tube
• Premium long-plate 12AX7/ECC83 variant
• Tests strong on a tube tester
• Rich harmonic content and excellent clarity
• Ideal for guitar amplifiers, hi-fi systems, microphone preamps, and studio equipment
• Carefully tested and ready for service

Whether you're upgrading a prized amplifier, restoring vintage audio equipment, or adding a rare tube to your collection, this ECC803S is an excellent opportunity to acquire a highly regarded vintage preamp tube.

Please review all photos carefully for condition and markings. Feel free to reach out with any questions.

Professionally packed and shipped with care. Check out my other listings for additional vintage tubes, amplifiers, and rare musical gear.

Note: Because Radiotron often sourced tubes from various premium European manufacturers, collectors may find these branded examples especially interesting. Please refer to photos for construction details and factory markings.