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JJ ELECTRONICS

💎 KT77 EL34 JJ Signature Matched Quad - NEW - 24h Burn-in - Amplitrex Curve Tested Tubes

💎 KT77 EL34 JJ Signature Matched Quad - NEW - 24h Burn-in - Amplitrex Curve Tested Tubes

€179,00 EUR
€179,00 EUR
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KT77 EL34 JJ Signature Matched Quad - NEW - 24h Burn-in - Amplitrex Curve Tested Tubes

MADE IN SLOVAKIA

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

The KT77 JJ Signature takes everything that's good about the KT77 JJ - musicality, transparency, and extended response - and takes it to the next level.
Thanks to 24-hour burn-in and matching to real Amplitrex dynamic curves , the sound acquires greater coherence, precision and depth.
The bass is tight and articulated, the mids are rich in harmonics, the highs are open and refined.
Each quartet is individually formed based on real dynamic measurements on Amplitrex and accompanied by an individual test card with the actual curve graph.
No generic pre-prints, no invented data : each curve is unique, like each valve.

Signature Selection Process – Advanced Technique and Total Transparency

  • Real 24-hour burn-in on Maxi-Burn station, to stabilize electrical characteristics
  • Testing of the Amplitrex AT-1000 at real operating voltages, with dynamic matching and symmetry verification
  • Complete analysis of characteristic curves , not just static values ​​(Gm, Ip)
  • Technical attachment with printed real curves and sealed numbered envelope

Sound character

  • Bass: tight and defined, with excellent control and natural rhythm
  • Mids: balanced, open and rich in musical harmonics
  • Highs: clear and airy, never sharp
  • Dynamics: ready, proportionate and engaging
  • Soundstage: wide, precise and well focused

🎧 Ideal for Hi-Fi systems with a transparent and musical character (Leak, Dynaco, Audio Research)
🎸 Perfect for guitar amplifiers with balanced tone and controlled dynamic response.

Test Specifications

Tubes tested on the Amplitrex AT-1000 Tube Tester at real-world operating voltages, with measurements taken after a 10-minute warm-up.

Additional tests performed:

  • Microphonics: Complies with hi-fi and musical instrument standards.
  • Output quality: excellent – ​​stable, strong and smooth output.
  • Short circuits / GAS: absent.

Each Signature Quartet is individually formed based on real dynamic measurements on Amplitrex, designed for those seeking the essence of sound, not a simple numerical reading, but a true assessment of electrical behavior.

Conditions

  • Supplied in our custom box for optimal protection.
  • Functionality: impeccable
  • Factory-new valves, tested and in perfect working order. 24-month legal warranty (consumers, Legislative Decree 206/2005). B2B: Articles 1490 et seq. of the Italian Civil Code apply.
    Returns for sound preferences/tube rolling are not accepted. 14-day returns are only accepted with an intact seal and unused tube. The warranty covers only original defects ; wear and tear , improper use , and tampering are excluded.

Additional Information

JJ tubes may exhibit slight variations in glass bulb height , with no impact on performance.

FAQ - Frequently Asked Questions:

  • Question: What do dynamic matching, full symmetry verification, and active curve analysis mean? Aren't the test data on the label enough?
  • Answer: The static data on the label tells us "how" a tube works. The actual curve shows "how" it works. It's a bit like knowing that a car can go 200 km/h...but without knowing how it accelerates, brakes, or holds its course. The dynamic curves allow us to select four tubes that "drive" in the same way during the musical journey.
  • Question: But on a sonic level, what really changes compared to a standard matching?
  • Answer: The sound gains in precision, detail, and stability. Bass is more controlled, the stereo image more focused, vocals more natural. Dynamic matching reduces tube dissonance and transforms the listening experience: more musical, more believable, more engaging.
  • Question: After installation, do they sound loud right away? Or do they need to be broken in?
  • Answer: They sound good right out of the box, but they get better with time. After just 50 hours, the bass becomes tight, and around 100 hours, the tonal balance stabilizes. Breaking in is part of the process that makes the sound more natural and engaging.
  • Question: What is 24-hour burn-in? And what about break-in?
  • Answer: No, it's a different technical step: before being tested, the valves are left on for 24 hours under controlled conditions. This serves to stabilize the internal parameters and eliminate unstable units. This way, the customer receives only reliable, already "settled" valves.

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

Condizioni di vendita e sicurezza

Anti-Tamper Security Seal Policy:
Each product is sealed to guarantee quality and integrity.
The right of withdrawal is subject to the seal remaining intact, as provided for by the Consumer Code.

Eco-Friendly Packaging:
The tube will be shipped with protective packaging to ensure safety during transport.
We use recycled and recyclable paper for packaging, along with brown ECO-KRAFT adhesive tape, eco-friendly and solvent-free.

Important Notes:
This tube, manufactured according to the standards of its era, is designed to operate in equipment compatible with vintage tubes.
It is recommended to follow standard safety guidelines to avoid malfunctions or damage.

Safety Assurance:
Although not tested according to modern GPSR regulations, this tube was designed to operate safely under the conditions for which it was manufactured.
We recommend using it only with equipment that supports vintage tubes, in order to avoid risks of malfunction or damage.
Technical data note:
In some cases, the technical data provided may be based on datasheets from other manufacturers or on equivalent historical specifications, when a specific official datasheet for the production batch of the listed item is not available.
Electrical characteristics may vary slightly depending on the production batch and manufacturing period, as is typical for thermionic components.

Safety Information:
Warning: Keep out of reach of children.
To be used under adult supervision.
Use the product only with equipment designed for vintage tubes.

Shipping & Returns

Shipping & Returns

Shipping Costs

Shipping costs vary depending on the total amount of the items in the cart and are calculated automatically during the checkout process.
All shipments are fully insured. The courier is automatically selected based on destination, weight, and shipment characteristics.

Shipping Times and Delivery

The indicated delivery times are purely indicative.
Any delays, storage issues, or operational changes made by the carrier (for example during peak periods such as holidays) are not attributable to Vacuum Tubes Treasures.

In such cases, we will nevertheless provide the Customer with all necessary support to open claims or assistance requests with the appointed courier.

International Shipping (Non-EU Countries)

For orders shipped to countries outside the European Union, any customs duties, import taxes, or additional charges are the sole responsibility of the recipient.
Vacuum Tubes Treasures has no control over these costs, which may vary from country to country. Customers are therefore advised to contact their local customs authorities prior to placing an order.

Warranty

All products sold by Vacuum Tubes Treasures are covered by the legal warranty of conformity, in accordance with Italian Legislative Decree No. 206/2005 (Consumer Code) and the Italian Civil Code (Articles 1490 et seq.), under the conditions set out below.

Warranty for Vacuum Tubes

Vacuum tubes, being components subject to wear and of vintage or specialized nature, are covered by a specific warranty of 6 (six) months from the date of delivery.
The warranty covers exclusively proven manufacturing or conformity defects that arise during proper use in accordance with technical specifications.

The warranty does not cover:

  • normal wear and tear,
  • subjective sound preferences,
  • use in incompatible equipment,
  • tampering or improper use.

Right of Withdrawal

Purchases made on the Vacuum Tubes Treasures website are governed by Italian regulations on distance contracts (Legislative Decree No. 206/2005).

Consumers have the right to withdraw from the contract within 14 (fourteen) days from the date of receipt of the goods, without providing any reason.

Conditions for Exercising the Right of Withdrawal

The right of withdrawal may be exercised only if:

  • the product has not been used,
  • the product is returned in its original condition,
  • the tamper-evident security seal is intact and not broken.

📌 Returns are not accepted for reasons related to sound preference, tube rolling, or subjective audio evaluation.
As with a music recording, a vacuum tube cannot be returned simply because its sound does not match personal taste.

Effects of Withdrawal

In the event of a valid withdrawal:

  • all payments received, including standard shipping costs, will be refunded,
  • refunds will be issued within 14 days from receipt of the returned goods,
  • the refund may be withheld until the goods have been received and inspected.

Refunds will be made using the same payment method used for the original transaction, unless otherwise agreed.

Return Shipping Costs

Return shipping costs are borne by the Customer, except in cases of:

  • verified defective products,
  • errors attributable to Vacuum Tubes Treasures.

In such cases, return shipping costs will be fully covered by us.

Damaged or Incorrect Items

If the Customer receives a damaged or incorrect item, it must be reported within 5 (five) working days from delivery, by email or telephone, clearly stating the issue.

Uncollected Parcels, Storage, and International Shipments

It is the Customer’s responsibility to monitor the shipment and promptly arrange for collection or customs clearance.
Any costs, delays, or losses resulting from:

  • failure to collect the parcel,
  • prolonged storage,
  • abandonment of the parcel at customs,

do not entitle the Customer to any refund.

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.