Listing Title:

Vintage 1958 RCA 12AX7 / ECC83 Red Tip Long Grey Plate – Matched Triodes (121/120) V1 Tested

Category:

Vacuum Tubes / Amp Parts

Condition:

Very Good (Used)

Description

Up for sale is a rare vintage 1958 RCA 12AX7 / ECC83 dual triode vacuum tube featuring original 17mm Long Dark Grey Plates and a Factory Red Tip (Low-Noise / Special Selection Marking).

Red-tipped vintage American tubes were specially selected at production for critical low-noise, low-microphonic applications. Paired with its virtually spot-on 1% triode match, this is an absolute top-tier candidate for a high-end Phase Inverter (V5), stereo hi-fi preamp, or ultra-quiet V1 input slot.

KEY FEATURE: Factory Red Tip Marking

Red Tip Designation: Indicates factory/OEM hand-screening for ultra-low noise floor and high-stability performance.

Dual-Stage Testing & Verification

This tube has undergone complete screening on the bench and under real-world high voltage:

Bench Screening (EICO 666 Tester):

Triode 1 Score: 121 (Strong Emission)

Triode 2 Score: 120 (Strong Emission)

Triode Balance: ~1% Match (Ideal for Phase Inverter or Stereo Hi-Fi balance)

Shorts / Leaks: PASSED (Zero heater-cathode shorts or internal leaks).

Gas Test: PASSED (Clean, stable operation).

High-Voltage Amp Audition (PRS Archon @ 400V+ DC):

V1 Input Slot Tested: Auditioned in the high-gain V1 position of a PRS Archon under full operating voltage.

Microphonics: PASSED. Tested via pencil/chopstick tap test under high gain—zero mechanical feedback, ringing, or microphonics.

Noise Floor & Tone: Exceptionally quiet noise floor. Delivers classic 1950s RCA 3D depth, sweet non-fatiguing top-end, and lush midrange bloom.

Details:

Brand: RCA (Radio Corporation of America)

Tube Type: 12AX7 / ECC83 / 7025

Special Marking: Factory Red Tip (Low-Noise / Premium Selected Grade)

Plate Construction: 17mm Long Dark Grey Plates

Year of Manufacture: Circa 1958

Origin: Made in USA

Ships securely packed in a sturdy box with generous bubble wrap via USPS Ground Advantage with tracking. Buy with confidence

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Listed5 days ago
ConditionVery Good (Used)
Very Good items may show a few slight marks or scratches but are fully functional and in overall great shape.Learn more
Brand
Model
  • 1958 RCA 12AX7 / ECC83 Red Tip Long Grey Plate – Matched Triodes (121/120) V1 Tested
Finish
  • Glass
Categories
Year
  • 1958

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