12AX7 (ECC83) NOS TELEFUNKEN Tested Tube - Ribbed Plates Diamond <> Bottom Made in Germany '60s
AMPLITREX Tested – Balanced Sections – Low Noise & Microphonics – Vintage TELEFUNKEN Production
Description:
This 12AX7 / ECC83 TELEFUNKEN NOS, produced in Germany in the 1960s and identifiable by the unmistakable Diamond <> mark printed in the glass at the base, represents one of the most famous and sought-after signal tubes ever made.
The construction with Ribbed Plates identifies the classic configuration of TELEFUNKEN production during the German company's period of maximum industrial maturity, appreciated worldwide for construction precision, exceptional longevity, and extraordinary tonal neutrality.
TELEFUNKEN ECC83 Diamond Bottom tubes are still considered an absolute benchmark for those seeking transparency, detail, and musical coherence, qualities that have made them key components in numerous European hi-fi, broadcast, and professional equipment.
This tube has been carefully tested using an AMPLITREX AT-1000, proving to be VERY STRONG, quiet, and perfectly stable.
Aesthetically, it is in good overall condition. The original markings are partially worn by time but still recognizable, while the tube body and internal structure remain well preserved, as shown in the photographs.
Sonic Characteristics
TELEFUNKEN Ribbed Plates are renowned for an extremely balanced and refined sound profile.
Unlike other vintage ECC83s that tend to characterize the sound more, these TELEFUNKENs aim for maximum fidelity and transparency.
Bass
The bass is precise, controlled, and articulate, with excellent definition of musical lines and no artificial bloat.
Mids
The midrange is extremely clean and natural, with a particularly credible and realistic reproduction of voices.
Highs
The highs are one of the strong points of this production: extended, airy, and detailed, without harshness or aggressiveness.
Dynamics
Dynamic response is fast and accurate, with excellent ability to follow the finest musical variations.
Soundstage
The soundstage is wide, stable, and well-focused, with excellent separation between instruments and performers.
🎧 Use in Hi-Fi Amplifiers
This TELEFUNKEN ECC83 is particularly suitable for:
- High-end tube preamplifiers
- MM and MC phono stages
- Integrated hi-fi amplifiers
- DACs and tube audio equipment
- Professional and broadcast equipment
- Restorations of vintage European electronics
The Low Noise & Microphonics selection makes it particularly interesting even for the most critical positions in the circuit.
🎸 Use in Musical Applications
TELEFUNKEN Diamond Bottom tubes are also highly valued in music for those seeking:
- Great note definition
- Excellent intelligibility
- Fast and precise dynamics
- Extremely linear response
Particularly interesting in boutique amplifiers, recording, and professional applications where transparency and detail are priorities.
🎯 Note for Audiophiles
Authentic TELEFUNKEN Diamond Bottom Made in Germany tubes represent one of the most sought-after ECC83s in the global vintage tube market.
Identification via:
- Original Diamond <> Bottom
- German production from the 1960s
- Ribbed Plates
- Authentic TELEFUNKEN construction
- VERY STRONG AMPLITREX test
- Low Noise & Microphonics
makes this example particularly interesting for both high-level audio use and collecting.
This tube still maintains very high electrical performance, exceeding the nominal average required for quality hi-fi use.
Test Results
Tested on AMPLITREX AT-1000 Tube Tester
Voltage Test: Va = 250V, Vg = -2V
Average 100%: Gm = 1600 ; Ia = 1.2 mA
TEST RESULT: VERY STRONG
Tube :
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Section 1: Gm = 1600 ; Ia = 1.2 mA
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Section 2: Gm = 1500 ; Ia = 1.0 mA
Additional Tests Performed:
- Microphonics: Low Noise & Microphonics – Tested and suitable for use in hi-fi systems and guitar amplifiers.
- Balance: The sections show consistent balance, fully compatible with use in hi-fi and musical amplifiers, in all applications where absolute symmetry between sections is not required.
- Emission Quality: Excellent – Very strong and stable emission, without fluctuations.
- Shorts and GAS: Absent.
Condition:
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Condition: NOS - New Old Stock - Tested and working - Supplied in our custom box for optimal protection.
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Functionality: Perfectly operational.
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Aesthetic condition: Good – Markings partially worn, but still legible. Tube body in good condition. See photos for details.
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Manufacturing Code: absent – TELEFUNKEN production, identifiable by construction characteristics. 1960s
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