About Vacuum Tube Supplies
Vacuum Tube Supplies not only sells tubes, we also specialize in the full service of vacuum tube and other electronic audio equipment. This includes: audiophile vacuum-tube pre-amplifiers and power amplifiers; guitar and other instrument vacuum-tube pre-amps and power amplifiers; solid state electronics, electronic keyboards, vintage radios, ham radios, and communications receivers.
We also will test up to 10 different types of your tubes at no cost, even if you don't need service or don't need to buy any vacuum tubes. This is much as they did in the US in the 1950s at the corner drug store!
Visit us at our workshop and warehouse located at 700 Mariposa Street, just west of the Art District on Santa Fe in Denver, Colorado.
Our hours are Tuesday through Friday, 10 am to 6 pm, Saturday 10 am to 4 pm. We are available other times by appointment. Call us at 303.534.5170. Feel free to send us an email at email@example.com with any questions you might have. You can also visit us online everyday at our ebay store: stores.shop.ebay.com/Vacuum-Tube-Supplies
Our specialized test equipment.
Our specialized test equipment includes: HP334A Distortion Analyzer capable of measuring distortion in the audio range below 0.01%; Tektronix Spectrum Analyzer Model 7L5 with tracking generator (option 25, L3) which is capable of measuring frequency <10Hz and up to 5 MHz less than 5uV; Tektronix Signal Generator/Source that can deliver a sine wave I/P of <0.03% distortion through the whole audio range; General Radio Output Power meter Model 1840-A; High performance 400MHz storage scope Tektronix model 7854 with numerous plug-ins; Hickok vacuum-tube testers models 539C, 539B which can match pre-amp and power tubes for plate current and Gm. (trans-conductance/mutual conductance); and numerous other test equipment including power sources (AC and DC), Variacs, Oscilloscopes, digital test meters, general purpose signal generators etc. We use various speaker cabinets for the ultimate test for sound: Wharfedale, Fisher and others.
How we test our tubes.
Before we sell or ship each tube is fully tested on our calibrated Hickok 539C tube tester. Every tube, whether used or NOS (New Old Stock) is tested for shorts using our Hickok 539C Ohm-meter. We don’t neon test for shorts, as it isn't a sensitive enough test. We test the tubes for shorts hot and cold to 50MOhms. We test all tubes for mutual conductance (sometimes referred to as trans-conductance) including each section, if applicable. Hickok 539C provides a minimum acceptable mutual conductance. We will not sell tubes that test at these minimums. Most tube manufacturers provide new tube mutual conductance range(s), and we test to these range(s). If a used or NOS tube is on the lower end of the manufacturer's range we discount the price of the tube. We try to post manufacturers' mutual conductance range(s), and the Hickok minimum values for each tube we sell, so you can make an informed decision on your purchase.
We also life test every tube. This is a test where the filament voltage is reduced by 10%, which gives an indication of the future performance of the tube. We discard any used or NOS tube that does not meet the life test. If any test results in failure for shorts, leaks or open filaments, we discard the tube, and will never list it.
Tube and box condition.
If we have doubts about the NOS status of a tube, we sell it as used, even if the tube has a good box. Remember, all of our tubes whether used or NOS are fully tested before we sell them. We sometimes have tubes with loose bases. Our policy is to note this in the description of the tube, and discount the price accordingly. We don’t sell any tube with a significantly loose base, unless the tube is exceptionally rare. If this is the case, it will be well noted in the tube's description. You can be sure that when we say a base is loose, it is only slightly loose and can be used as-is. Some of our tubes come with original boxes. If the used, NOS or NIB tube description does not indicate the tube is packed in its original box, it will be packed in a new, standard white box. If a used, NOS or NIB tube has an original box, we will also describe its condition, as often the box is just as interesting and collectable as the tube itself. If any used, NOS or NIB tube has an original box in poor condition and we pack it in a new standard white box, we will give you the original box as well. Since we open all boxes to test them, sometimes the box flaps or tabs are damaged and we will note this in the description of the tube.
We warrant everything we sell. We do not sell as-is, unless specifically indicated in the item description. Used and New Old Stock (NOS) vacuum tubes have a 30 day warranty from date of purchase. New in Box (NIB) vacuum tubes have a 90 day warranty from date of purchase.
Our shipping practices.
In the US, we generally ship via US Postal Service priority mail. This provides traceability and generally arrives within 2 to 3 days of shipment. We can purchase insurance on your behalf, if you contact us and let us know you would like this service. Outside the US, US Postal Service 1st class international air mail is a good value and - depending on location - arrives within 6 to 14 days of shipment. We can't track all shipments leaving the US, unless they are shipped via a more expensive method of shipment (for example US Postal Service priority international mail). If you would like tracking, please contact us for an estimate before purchasing.
Our return policy.
Within 7 days of receipt, if you are not delighted with your purchase, let us know and we will authorize return of the item. Authorization is required before a return is accepted. There are no cash refunds after 14 days only store credit. The following items cannot be returned: anything cut to length (wire, G-10 board, etc.), consumables (solder, solvent, etc.). We may be able to provide another item from our large inventory, if we have additional stock. To improve our quality and service, we would like to understand the reason for the return. Returns must include the original box in the same condition (if applicable), and be packed in the original packaging. Purchaser must pay return shipping fees. When we receive the return, we will refund your purchase price (excluding original shipping fees) within 72 hours.
Inspect your order immediately on receipt. If the package and/or item is damaged in shipping, and you took the optional insurance, notify the carrier immediately. When you file your claim with the carrier, we will be happy to help you in any way we can. We want you to be happy with your purchase, and will work with you if you have any concerns or problems. Please contact us to work out a mutually beneficial solution.
IMPORTANT - BE SAFE!
By their very nature, vacuum tubes, vacuum-tube equipment and associated components operate at inherently high voltages, currents and can be very hot! We want you to be safe and enjoy your equipment, whether you do this as a hobby or as a business. It is important to work within your capabilities. If you are not trained or qualified or comfortable working with such equipment seek out professional help, rather than put yourself or others at risk. Protective shields, covers, interlocks and the like are installed for your protection. Do NOT remove them unless you have the knowledge or qualification to do so. Vacuum tube equipment and components can cause serious injury or death. Vacuum Tube Supplies LLc and its associates shall NOT accept any direct, indirect or consequential damages out of the use or purchase of any of our products or services we provide, regardless of the method of delivery to you, including, but not limited to, personal injury or loss of income. Under no circumstances will our liability exceed the purchase price of the product or service provided.