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KEN-RAD

6SN7GT VT-231 KEN-RAD Black Plates Black Glass Foil Getter – Matched Pair – Made in USA 1940s

6SN7GT VT-231 KEN-RAD Black Plates Black Glass Foil Getter – Matched Pair – Made in USA 1940s

Regular price $238.00 USD
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6SN7GT ( VT-231 ) KEN-RAD Black Plates Black Glass Foil Getter Matched Pair Made in USA '40s

One of the two valves has a visible crack on the plastic base (see photo), which does not affect its functioning

The 6SN7GT VT-231 KEN-RAD , in this version produced in the United States during the early to mid 1940s, represents one of the most sought-after incarnations of the 6SN7 family. Featuring short black plates , foil getters , and black glass bulbs , these tubes are universally recognized for their deep, authoritative, and densely textured sound.

The VT-231 military-grade construction ensures rigorous selection , low noise , and electrical coherence , while the proposed pair is carefully matched , perfect for reference stereo applications, tube power amplifier driver circuits, or high-fidelity preamplifiers.

Bass : Intense and anchored. The low range is full-bodied, stable, and layered , with an almost tangible physical presence. It delivers harmonic weight and a well-defined rhythm , ideal for full-range systems or live recordings.

Mids : Warm and punchy. The Ken-Rad's mids are vibrant yet controlled , with richly textured voicings and a velvety tonal texture that delivers every nuance with realism and musicality. There's never a harshness, even on complex signals.

Highs : Sweet but present. The top end is silky, natural, and never sharp , with a soft yet well-defined brilliance that adds air and detail without ever overwhelming the musical message.

Dynamics : vigorous and structured. The dynamic response is decisive yet fluid , with excellent harmonic swing and a consistently controlled behavior, even at peaks. The valve can be muscular or delicate depending on the context.

Soundstage : three-dimensional and dense. The stereo image is wide yet compact , with an impression of real depth , rich in environmental micro-information. The positioning of the sources is credible, stable and sculpted .

🎧 Use in Hi-Fi Stereo Amplifiers, Preamps and Driver Stages
This matched pair is ideal for 2A3/300B power amplifier driver circuits, low-noise preamplifiers , or dual mono configurations. The full, refined sound makes it an excellent choice for those seeking tonal coherence, warmth, and controlled dynamics , particularly effective on full-range systems or with high-sensitivity speakers .

🎸 Use in Music Amps and Studio Gear
Less common in guitar, but occasionally used in tube studio preamps and custom high-voltage designs , the Ken-Rad offers a warm, rounded tone that's ideal for audio chains where presence without harshness is desired.

🎯 Note for audiophiles and technicians
One of the most iconic tubes in the 6SN7 series, with an authoritative voice and military-grade construction . Black glass provides internal shielding, while the VT-231 selection guarantees stability and longevity. The matched pair is perfect for high-end applications where transparency, warmth, and three-dimensionality are priorities.

Test Results:

Valves tested on Amplitrex AT-1000 Tube tester:

  • Test Conditions: Va = 250V, Vg = -8V
  • Average 100% Gm = 2600 ; Ia = 9.0 mA
  • Test Result: VERY STRONG

Valve 1:

  • Section 1: Gm = 2600 ; Ia = 10.4 mA
  • Section 2: Gm = 2500 ; Ia = 9.2 mA

Valve 2:

  • Section 1: Gm = 2600 ; Ia = 9.8 mA
  • Section 2: Gm = 2700 ; Ia = 11.6 mA
Additional Tests Performed:
  • Microphonics: Standard. Tested and approved for use in hi-fi and guitar amplifiers. Not recommended for use in high-sensitivity guitar amplifiers.
  • Output Quality: Excellent – ​​Very strong and stable output, no fluctuations.
  • Short circuits and GAS: Absent.

Conditions:

  • Condition: Vintage tubes - Tested and in perfect working order. Shipped in our custom box for optimal protection.
  • Functionality: Fully functional.
  • Aesthetic conditions: One of the two valves has a visible crack on the plastic base (see photo), which does not affect its functioning. The lettering is in excellent condition, with minimal signs of aging. See photos for details.
  • Manufacturing Code: P4 - Made in KEN-RAD USA - Code not decipherable, year of manufacture detected by internal structure

Burglar-Resistant Security Seal Policy:

Each product is sealed to ensure quality and integrity.
The right of withdrawal is subject to the tamper-proof seal being kept intact, as required by the Consumer Code.


Eco-friendly packaging:

The valve will be shipped in protective packaging to ensure safety during transportation.
We use recycled and recyclable paper for packaging, and brown tape ECO-KRAFT , eco-friendly and solvent-free.


Important Notes:

This tube, manufactured to the standards of the time, is designed to work in equipment compatible with vintage tubes.
It is recommended to follow the safety guidelines to avoid malfunctions or damage.


Security Guarantee:

While not tested to modern GPSR regulations, this valve has been designed to operate safely under the conditions for which it was manufactured.
We recommend using it with equipment that supports vintage tubes, to avoid the risk of malfunction or damage.

Important note: The technical data shown is based on another manufacturer's datasheet, as a specific datasheet for the production of the item in the catalog is not available. Features may vary slightly depending on the batch and production.


Safety Information:

  • Attention: Keep out of reach of children.
  • To be used under adult supervision.
  • Use this product only with equipment designed for vintage tubes.

Find out why our valves 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.

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.