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JJ ELECTRONICS

KT77 EL34 JJ Matched Quad AMPLITREX Tested Tubes -NEW- 4 Valves IN ORIGINAL BOX

KT77 EL34 JJ Matched Quad AMPLITREX Tested Tubes -NEW- 4 Valves IN ORIGINAL BOX

1.137,00 DKK
1.137,00 DKK
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KT77 EL34 JJ Electronics Matched Quad – AMPLITREX Tested – New Production – Original Box

MADE IN SLOVAKIA

General Description

The KT77 is an octal beam power pentode, usable in the vast majority of amplifiers designed for EL34. Compared to EL34 and E34L, it offers greater available power, more authoritative bass, and superior headroom, while maintaining a high level of detail and balanced tonal rendition.

The KT77 JJ represents one of the most successful modern interpretations of this historic tube: a production designed to ensure reliability, electrical consistency, and high-level sonic performance.

The tubes are NEW, supplied in their original JJ box, and carefully selected and matched in our laboratory using AMPLITREX, to ensure stable, uniform, and repeatable operation within the amplifier.

An extremely popular choice as an advanced alternative to the EL34, the KT77 JJ retains its underlying musicality while adding control, extension, and authority.

Sonic Characteristics

The tonal character of the KT77 JJ is modern, balanced, and solid, with a consistent response across the entire audio spectrum.

Bass: Deep, controlled, and well-articulated. The low end is compact and fast, with a feeling of greater substance compared to a traditional EL34, also ideal for amplifiers with generous transformers.

Mids: Rich, present, and well-structured. Vocals sound natural and well-sculpted, with excellent intelligibility and without excessive coloration.

Highs: Open, orderly, and well-extended. The extreme high end is clean and detailed, never aggressive, suitable even for high-resolution systems.

Dynamics: Reactive and controlled. The KT77 JJ responds promptly to transients and conveys a sense of constantly managed power, proving versatile and musical across a wide variety of genres.

Soundstage: Wide and stable soundstage, with good depth and proper instrument separation. The image is focused and credible.

🎧 Use in Hi-Fi Amplifiers

Ideal for EL34 / KT77 compatible amplifiers, both in push-pull and single-ended configurations where provided. An excellent choice for those seeking greater control and definition, without sacrificing musicality.

🎸 Use in Musical Applications

Also highly appreciated in guitar amps, where they offer a firmer and more defined sound compared to the EL34, with superior headroom and a more compact and controlled low-frequency response.

🎯 Note for audiophiles and technicians

  • factory new,
  • tested and matched on AMPLITREX,
  • supplied in original packaging,
  • designed for those who desire modern reliability and a solid, balanced, and authoritative sonic performance.

An ideal quartet for upgrading or maintaining EL34-compatible amplifiers at the highest level, with the assurance of a professional Vacuum Tubes Treasures selection.

Test Specifications

Tubes tested on Amplitrex AT-1000 Tube Tester
Measurements taken after 10 minutes of warm-up

Additional tests performed:
• Microphonics: standard – compliant for use in hi-fi and musical instruments
• Emission: excellent – strong and stable emission
• Short circuits and GAS: absent

The quartet is matched exclusively on real static parameters, to ensure consistency, reliability, and symmetry between the two channels.

Conditions

• Supplied in original box
• Functionality: impeccable
• Factory new, tested, and perfectly working tubes

Warranty:
• Consumers: 24 months (Legislative Decree 206/2005)
• B2B: articles 1490 et seq. of the Civil Code apply

Additional information

JJ tubes may have slight differences in glass envelope height, with no impact on technical or sonic performance.

🔍 Find out what we really think: read our complete guide to the 6550 JJ.

Terms of Sale & Safety

Sales Terms & Product Safety

Each vacuum tube is carefully selected, tested, and verified in our laboratory before shipment. Where stated in the listing, test results, matching data, and declared characteristics refer to measurements performed using the specified test equipment and operating conditions.

Sound descriptions are provided for guidance only and reflect the characteristics generally associated with that particular tube type. Personal sound preferences, tube rolling, or perceived differences between audio systems do not constitute a product defect.

Before installation, please verify the tube’s electrical and mechanical compatibility with your equipment and follow the manufacturer’s instructions.

New production and NOS tubes are shipped with a tamper-evident security seal and internal technical documentation to ensure traceability of the product’s condition at the time of shipment.

Product Safety (GPSR)

Vacuum tubes are electronic components intended exclusively for use in compatible equipment and must be installed in accordance with the equipment manufacturer’s instructions.

Due to their historical or vintage nature, certain technical specifications may be based on original datasheets or equivalent technical documentation when documentation from the specific manufacturer is unavailable.

Use only with suitable equipment. Keep out of reach of children.

Shipping & Returns

Shipping & Returns

We ship worldwide using carefully selected express carriers and protective packaging specifically designed for vacuum tubes.

If you change your mind, you may exercise your right of withdrawal within 14 days of delivery, where applicable under the relevant consumer protection laws. The product must be returned complete with its original packaging and accessories, in the same commercial condition in which it was received. Return shipping costs are the responsibility of the customer.

Every returned item undergoes a technical inspection. Installation, use, tube rolling, or any other handling may reduce the product’s commercial value and may affect the refund amount, in accordance with applicable law.

If you believe the product has a lack of conformity, our laboratory will carry out the necessary inspections and apply the remedies provided by the applicable consumer protection legislation.

For further details, Customers are invited to consult the “Terms and Conditions” and “Refund Policy” sections of our website, or to contact us before placing an order.

Vacuum Tubes Treasures
www.vtt.store | www.vacuumtubestreasures.com
📧 info@vacuumtubestreasures.com

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  • ATTENTION PLEASE

    Please understand that the writing on the glass of vintage valves has become very delicate over the years and comes off easily. You must handle them with extreme care to avoid this. Wear and damage to the writing on the valves reduces their market value and causes damage. Please exercise extreme caution.

  • ATTENTION PLEASE

    We wish to inform you that any attempts to manipulate shipping destination information in order to obtain lower shipping rates may be considered fraudulent acts. Please provide accurate information and contact us if you have any concerns. We reserve the right to review and, if necessary, cancel orders that we deem to be in violation of our conditions. Thank you for your understanding and cooperation.