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Single Audio Research KT91 (Ei KT90) Vacuum Tube Reference 300/600 - Many Avail

Description: Extraordinarily rare Yugoslavian Ei KT90, labeled with Audio Research's KT91 number. This is the sought-after Type 2 version, with spot welded inner and outer plates. Previously owned & have been used, but test strongly. The sale is for a single tube, but I have many available. Choose the quantity you want from the drop-down. Test results are shown below; I can honor requests for specific tube(s) if I still have them. Please inquire before you purchase if you want specific tube(s). International buyers please note: the default shipping service is now Fed-Ex International Connect Plus. This is an express upgrade over the old standard USPS First Class Mail, at a comparable cost, with faster in-transit times and detailed end-to-end tracking. Parcels typically arrive to most locations around the world in a week or less. Buyers from China: please contact me for shipping cost. Test results are as follows, tested on the Maximatcher 2 as 6550s. Minimum good for a 6550 is 3200umhos @ 20mA. These test as would be expected for a strong 6550 on this tester. 4650umhos@33.8mA4960@37.24720@32.84950@37.34820@35.54950@35.55010@39.54860@35.04780@38.64850@36.94960@35.64850@36.94970@39.34800@34.14750@35.6 ******************************** Be sure to read my policies below, and contact me before you purchase if you have any questions. I have over 30 years of experience as an electronics engineer, certified electronics technician, and hobbyist, and have been collecting, buying, and selling tubes since the 1980s. I've been an eBay seller since February of 2000. This is the only seller account I have on eBay and the pictures you see are of the actual tube(s) you’ll receive (unless you are buying from a multiple-quantity lot, in which case the tube shown will be representative). Do you have tubes to sell? Search for me and send me pictures and/or a list of your inventory!Testing Tubes are described, tested, and presented to the best of my ability, subject to the limitations of the equipment that I have available (Amplitrex AT1000, MaxiMatcher 2, Hickok 539C, and Hickok 6000A). Test results are likely to differ between your equipment and mine due to many factors. Also be aware that “matched” tubes might not match on your equipment, if operated/tested under conditions that differ from those of my test equipment. Small signal (i.e. 12AX7) tubes are generally checked for noise and microphonics; power tubes (i.e. 6L6) are usually not. However, please keep in mind that the results of this test are subjective and may not be acceptable for your application. Nominal values are given for reference on many tubes. A tube may measure greater than or less than nominal – by as much as 20% - and still be an unused, NOS tube. Please send me a message if you have a question or need clarification about how I test and match tubes.Return Policy Unless otherwise stated in this listing, tubes may be returned within 30 days for a refund. Please keep in mind that while I do allow returns, my purpose here is to sell tubes, not to loan tubes for rolling. Any tube to be returned must: a) still bear my identification stamp. b) be in EXACTLY the same condition in which it arrived to you. Things which may invalidate a return: defaced or smudged print on the glass, bases scratched from retainer springs, cracked or damaged glass, damaged or missing boxes (where original boxes were sent with the tubes), and electrical or physical degradation from improper operation or handling. Returns which do not meet the above criteria may be refused or may be subject to partial refund. I pay for return shipping on all returns within the USA, regardless of reason. You pay for return shipping if you are located outside of the USA. If the tube arrives to you DOA or significantly not as described (SNAD), I pay for return shipping. International buyers, please note: import fees and taxes which you pay to your border and/or customs agency are not refundable by me under ANY conditions or for ANY reason, regardless of the reason for your return.Shipping Your tubes will be professionally prepared for shipping using all-new packing materials and will arrive to you in perfect condition. I've been shipping tubes for many years and know how to get them to you quickly and securely. International orders ship with proper customs documentation (and tax code or IOSS number, where applicable) to ensure that they're processed with minimal delay upon arrival in the destination country. DOMESTIC: Unless otherwise noted, free USPS shipping is offered on all tubes purchased with Buy-It-Now. If you prefer a different shipping method, please contact me prior to purchasing. I can usually ship (at additional cost) via any USPS, FedEx, or UPS method that is applicable to your ZIP code. If you need expedited shipping (Express, Next Day, etc.), please contact me first to confirm earliest available date of shipment, as cutoff times are generally early in the afternoon. INTERNATIONAL: Fed-Ex International Connect Plus is the default service for shipments sent outside of the USA. It is fast and reliable, with end-to-end tracking. If you prefer a different shipping method, please contact me prior to purchasing. I can usually arrange shipping with USPS, UPS, or DHL at additional cost, but these alternatives are decided on a case-by-case basis and might not be available to your address and/or country. Ebay places the burden of safe delivery on sellers, so I fully insure all shipments sent outside of the USA, regardless of value. Because I can insure only up to the declared value, ALL SHIPMENTS ARE DECLARED AT ACTUAL VALUE. You might owe significant import fees on higher value shipments once they cross your country's border – check with your border or customs agency for details. I can ship to a domestic freight forwarder or other third party within the USA, provided their address is on the order at the time you place it. GENERAL: SIGNATURE REQUIREMENT: All orders valued at USD$750 or greater require a signature release upon delivery. Someone at your delivery address will need to be available at the time of delivery to sign for the package. COMBINED SHIPPING: I'm happy to combine shipping on multiple purchases. Those shipping within the US will combine automatically. International orders must be manually combined after the purchase, and any excess shipping will be refunded to your payment source (due to the way eBay buy-it-now items are set up, this is the only way I can combine shipping on more than one item). HANDLING TIME: My handling time is one business day and eBay requires me to ship within that timeframe. I cannot withhold shipment for a later date. If you require shipment on a specific date I can often set up a special listing just for you on that date; please inquire. I usually ship every day of the week, except for Sunday and USPS-observed holidays, and orders often ship same day. Orders placed later in the day usually ship next business day. Orders placed on Friday or Saturday will sometimes not ship until Monday. All orders placed on Sunday or USPS-observed holidays ship the next business day. Expedited and express shipments (FedEx and UPS 2-day & Next Day, etc) must be placed by 12PM Pacific Time in order to ship same day. If you have an urgent delivery need it's a good idea to contact me first so I can confirm exact day of shipment. SHIP-TO ADDRESS: Ebay requires that I ship to the address on the order. This protects both you and me. I cannot ship to a different address. If you require shipment to a different address please update your shipping information before making a purchase. R36

Price: 120 USD

Location: Ashland, Oregon

End Time: 2024-11-04T21:04:37.000Z

Shipping Cost: N/A USD

Product Images

Single Audio Research KT91 (Ei KT90) Vacuum Tube Reference 300/600 - Many AvailSingle Audio Research KT91 (Ei KT90) Vacuum Tube Reference 300/600 - Many AvailSingle Audio Research KT91 (Ei KT90) Vacuum Tube Reference 300/600 - Many AvailSingle Audio Research KT91 (Ei KT90) Vacuum Tube Reference 300/600 - Many AvailSingle Audio Research KT91 (Ei KT90) Vacuum Tube Reference 300/600 - Many AvailSingle Audio Research KT91 (Ei KT90) Vacuum Tube Reference 300/600 - Many AvailSingle Audio Research KT91 (Ei KT90) Vacuum Tube Reference 300/600 - Many Avail

Item Specifics

Restocking Fee: No

Return shipping will be paid by: Seller

All returns accepted: Returns Accepted

Item must be returned within: 30 Days

Refund will be given as: Money Back

Brand: EI

Type: Vacuum Tube

Model: KT90/KT91

Country/Region of Manufacture: Serbia

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