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6BQ5 / EL84 HAMMOND by Ei Gray Plates Halo Getter Matched Quad Tubes Made in YUGOSLAVIA

6BQ5 / EL84 HAMMOND by Ei Gray Plates Halo Getter Matched Quad Tubes Made in YUGOSLAVIA

€119,90 EUR
€119,90 EUR
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6BQ5 / EL84 HAMMOND by Ei Gray Plates Halo Getter Matched Quad Tubes Made in Yugoslavia

AMPLITREX Matched Quad – VERY STRONG – Vintage Ei Production for HAMMOND

General Description

This matched quad of 6BQ5 / EL84 HAMMOND by Ei Niš, Made in Yugoslavia (today Serbia) production, represents a particularly interesting selection for enthusiasts of the best classic European EL84s.

The tubes were produced by Elektronska Industrija (Ei) and branded for HAMMOND, a historic manufacturer of professional electronic organs. The construction with Gray Plates and Halo Getter, combined with the same manufacturing code KM4 ◉7I, indicates homogeneous production from the same batch.

A curious and interesting detail is the presence of the “Made in Germany” marking on the tube’s printing. However, the manufacturing code KM4 ◉7I unmistakably identifies the actual producer as Elektronska Industrija (Ei), Yugoslavia, a conclusion further confirmed by the characteristic construction features typical of this highly regarded European production.

Early Ei productions are highly valued by enthusiasts because they derive from technologies and manufacturing equipment closely linked to the European tradition of signal and power tubes. Even today, they are considered among the most interesting vintage alternatives to Western-produced EL84s.

This quad has been carefully tested using an AMPLITREX AT-1000 Tube Tester, proving to be VERY STRONG, with very close values among the four tubes, stable emission, and having passed the 48h Burning Test.

From an aesthetic point of view, the tubes are in good overall condition. The HAMMOND markings show normal wear and tear over time, as visible in the photographs, while the internal structures are well preserved.

Sonic Characteristics

EL84 Ei tubes from this period are appreciated for their ability to combine musicality, dynamic liveliness, and excellent intelligibility of the musical message.

Bass

The bass range is fast, well-articulated, and controlled. It doesn't aim for artificial emphasis but offers precision and good rhythmic definition.

Mids

The mids represent one of the strengths of this production. Vocals sound natural and well-focused, while acoustic instruments and guitars maintain a rich and engaging harmonic texture.

Highs

The highs are open, detailed, and well-extended, with a lively but generally balanced presentation.

Dynamics

The dynamic response is prompt and reactive, a quality particularly appreciated in both hi-fi and musical instrument amplifiers.

Soundstage

The soundstage appears well-organized and stable, with good instrument separation and accurate spatial reconstruction.

🎧 Use in Hi-Fi Amplifiers

This matched quad is particularly suitable for:

  • EL84 / 6BQ5 based push-pull amplifiers
  • vintage integrated amplifiers
  • compatible Hammond electronics
  • European and American hi-fi restorations
  • audio projects requiring consistent and reliable quads

The low microphonics and good matching also make it suitable for particularly demanding applications.

🎸 Use in Musical Amplifiers

EL84 Ei tubes are also highly appreciated by musicians due to characteristics such as:

  • excellent harmonic response
  • lively dynamics
  • definition in the mid-high frequencies
  • good note intelligibility
  • stable performance over time

They can represent an interesting choice for guitar amplifiers that use EL84 quads and seek the typical character of vintage European productions.

🎯 Note for Audiophiles and Technicians

This quad combines numerous elements particularly appreciated by enthusiasts:

  • original Ei Yugoslavia production
  • HAMMOND brand
  • same manufacturing code
  • Gray Plates
  • Halo Getter
  • Matched Quad
  • 48h Burning Test – OK
  • VERY STRONG performance

A particularly interesting vintage selection for those who desire an authentic, consistent, and musically convincing EL84 quad, from one of the most appreciated European productions of the period.

Tested on AMPLITREX AT-1000 Tube tester:

Voltage Test: Va = 250V, Vg2 = 250V, Vg1 = -7.3V
Average 100% Gm = 11.3 ; Ia = 48 mA
TEST RESULT: VERY STRONG

  • Tube 1: Gm 10.90 ; Ia = 47 mA
  • Tube 2: Gm 10.90 ; Ia = 47 mA
  • Tube 3: Gm 10.87 ; Ia = 43 mA
  • Tube 4: Gm 10.55 ; Ia = 42 mA

Additional Tests Performed

  • Burning Test: 48h – OK
  • Microphonics: Low. Tested and suitable for use in hi-fi and guitar amplifiers.
  • Emission Quality: Excellent – very strong and stable emission, without fluctuations.
  • Shorts and GAS: Absent.

Condition

  • Condition: Vintage Tubes - Tested and perfectly functional. Supplied in our custom box for optimal protection.
  • Functionality: Perfectly operational.
  • Aesthetic Condition: Good – Markings partially eroded, but still legible. Tube body in good condition. See photos for details.
  • Manufacturing Code: KM4 ◉7I → ◉ indicates the manufacturer, namely Elektronska industrija, YUGOSLAVIA. 7I → 7 indicates 1967, I indicates the month of September.

Discover why our tubes are different →

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.