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Some Questions about the tubes we sell.

What is your minimum order?

Minimum order is $5 excluding shipping.

What does NOS mean?

NOS means "new old stock."  Old stock that is in new condition.

What does "like new" mean?

"Like new" means the tube has been used low hours, but still tests like a NOS tube. The "like new" tube might also have some scratches on the base, glass, or poor printing on the base or glass.

What is a "Kuhl-Tube"?

Pronounced (kool-toob). Tube World's cryogenic process takes select vacuum tubes and deep-chill anneals them in liquid nitrogen (LN2) for 36 hours at -193° Celsius / -320° Fahrenheit in our own cryogenic chamber, producing a superior sounding vacuum tube called a "Kuhl-Tube."  Kuhl-Tube is a trademark of Tube World, Inc.

Am I going to receive the tube in the photo?

Yes, the tube (or other product) in the photo of the item you buy is the exact item you will receive. We take our own photos of the products before we list them.

If you see one (1) tube in the picture, you are purchasing one (1) tube.  If you see two (2) tubes in the picture you are purchasing two (2) tubes, etc.

Where do you buy your tubes?

From hundreds of sources, all over the world.


Questions about shipping.

How do you pack and ship the tubes?

We package your tubes very carefully. We're proud to tell you that we have had very few instances of damage during shipping over the past 27 years. 

Shipping options to most countries:

USPS Express Mail (USA and foreign) (fastest mail service)

USPS Priority Mail (USA and foreign)

USPS Ground Advantage (USA)

USPS Airmail (foreign)

Worldwide (DHL) (foreign destinations) (fastest service) (BEST VALUE)

UPS Ground (USA and Canada destinations)

UPS Next Day and 2-Day (USA destinations)

UPS Expedited (foreign destinations) (BEST VALUE)

UPS Saver  (foreign destinations) (fastest service)

Some airmail shipments do not have a detailed tracking number and therefore cannot be tracked at usps.com. We recommend shipping orders over $250 by USPS Priority Mail Express, DHL or UPS.

Delivery speeds will vary depending on the country you live in. This can be for a variety of reasons, but primarily because of customs delays. Packages can be held in customs for longer periods of time in some countries versus others.

When will my order be shipped?

Your order will be shipped typically within 24-48 hours after the receipt of your order.  You will be notified by email on the receipt of you order and if any changes need to be made to your order.  You also will be notified by email when your order ships.


Questions about tube testing.

Have you tested the tubes?

Unless stated otherwise, all tubes listed are tested.

How do you test the tubes?

We test tubes on one or more of the following pieces of test equipment:

  • Amplitrex AT1000 Digital Tube Tester
  • Space Tech Labs Canada custom headphone preamp (test for preamp tube noise and microphonics: 12AX7, 12AU7, 12AT7, 6922, 6SN7, 6SL7, 5687, 5670, 6AB4 and 100+ other types)
  • TV-7D/U military tube tester
  • B&K tube tester

Tubes are tested for:

  • Audio power tubes are tested for: good idle current, linear and evenly spaced plate curve traces, transconductance (Gm) within specifications, gas, shorts, leakages, and instabilities
  • Preamp tubes are tested for; (Gm) Transconductance, shorts, gas, leakages and manufacturers defects.
We stock thousands of different NOS and used vacuum tubes made from 1915-present for many different applications. 95%+ of the tubes we sell can be tested. Most of these are tubes designed for audio equipment, guitar amplifiers and radios, etc. About 5% of the tubes we sell cannot be tested. These 5% are normally very obscure transmitting tubes, CRT tubes or tubes that we don't have the proper test equipment or circuitry to test them in. You will be notified if a tube cannot be tested. These tubes will be sold as plug-n-play tubes to see if they operate correctly in your equipment. If they do not, you will receive a 100% refund. Call or email tekman@tubeworld.com if you have any questions regarding tube testing or matching.
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