2 PAIRS OF ULTRA RARE SYLVANIA 6SL7W METAL BASE VACUUM TUBESOffered is two pair of ULTRA RARE Sylvania 6SL7W metal base vacuum tubes. These are one of the earliest and scarcest of the 6SL7 varieties, and are much more difficult to find than their 6SN7 metal base or 5691 counterparts. All four tubes appear to have the same date code of 'I5', and the US Navy anchor insignia. These are military pulls and are to be considered USED. Physically they appear to be in good shape, albeit a little dusty. Price for pair #1 is $250. Price for pair #2 is $225. Take both pairs for $450. The price is exclusive of any shipping and Paypal fees. Yes – the price is high (and some would say exorbitant) for 6SL7 tubes. My only response is - go find these somewhere else, because they almost never come up for sale. I tested these on my Weston 981 III, where min (65%) is 1040, making about 1600 'theoretical' 100%. The results are as follows: Pair #1 - 1850/1700 and 1750/1700 Pair #2 - 1700/1650 and 1600/1650 Because of the high price I am asking, I went to the added step of testing these on a Kaye Small Signal Tube Checker, which provides an INDICATION of noise, microphonics, gain and distortion. I do not use this piece of equipment very often, and I am not sure if it is even performing up to spec, but it does provide what I believe to be useful comparative information. The noise and microphonics tests are totally subjective as they involve actually listening (the unit has a built in speaker as well as a headphone jack), and I do not have a lot of experience judging, but here is my view. These tubes all appear to be low noise and low in microphonics, but they are NOT ultra low on the Kaye Tester as I can induce a microphonic response under non-ideal conditions. I have had other 6SL7s where I cannot get them to ring, and I have had others that ring just because you look at them. These are clearly better than average, but not the best I have ever tested. The gain test is supposed to measure the gain of a tube in a class A circuit, cathode bypassed, with a -10 db 500 hz tone applied to the grid (please don’t ask me what this signifies), and involves reading a meter. All tubes seemed balanced and gave about the same gain reading, which (in view of Gm) supports the pairing. What was exceptional about these tubes was the output/distortion test, which is supposed to show the maximum output a tube can produce at 10% distortion. These tubes were better than any others (of any type) I have ever tested. I do not, however, know how this might translate to sound. I can provide additional pictures upon request. GENERAL TERMS AND CONDITIONS - PLEASE READ CAREFULLY Please note that these tubes are being sold 'AS IS', but I will guarantee against a material misdescription in the listing. In such event, I will refund purchase price less shipping upon return of the tubes in the same condition as sent. PLEASE NOTE THAT I CANNOT GUARANTEE (OR EVEN REMOTELY PREDICT) HOW THESE TUBES WILL SOUND OR PERFORM IN YOUR EQUIPMENT. THE TEST RESULTS ARE ONLY PROVIDED AS AN INDICATION OF TUBE PERFORMANCE IN A VERY LIMITED (AND NON-IDEAL) ENVIRONMENT. OTHER THAN AS SET FORTH ABOVE, I EXPRESS DISCLAIM ANY LIABILITY WITH RESPECT TO THESE TUBES OR RESPONSIBILITY FOR YOUR USE OF THEM. Money order/cashiers check/personal check preferred, but all (other than US Postal money orders) must clear my bank first. I also accept Paypal for convenience (but add 3.2% to the total). I am willing to ship globally but, outside of the USA and Canada, more stringent payment and shipping conditions apply. In any case, the buyer is responsible for all shipping charges. Contact me for a quote. Please check my feedback on Audiogon, Videogon and Ebay (ID=baileyler) and buy with confidence. For search purposes – amplifier vacuum electron tube valve rectifier stereo guitar audio preamp preamplifier 6SN7 6SN7W 6SN7A 6SN7GT 6SN7GTA 6SN7GTB 6SN7WGTA 5691 5692 VT231 VT-231 6SL7 6SL7W 6SL7GT 6SL7WGT VT-229 VT229 CV181 ECC32 ECC33 ECC34 ECC35 1578 6N8S 6N9S 6H9C
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