Matched quad SVETLANA EL34 Winged C Tubes B&K Tested Very Strong at 105%Prima di loro solo le Mullard.

6550 Svetlana SEC Match Tested Pair. Up for sale is a rare pair of vintage matched Svetlana “Winged C” logo 6550’s. This is the best Russian production 6550 ever made. Fully Amplitrex tested strong in fixed bias mode @ 500V, see images for results. These saw light use in an Audio Research Power Supply. Tubes will ship in generic white tube boxes via USPS PRIORITY MAIL. Due to the nature of vintage/used vacuum tubes, these are being sold AS-IS with no returns accepted. I will guarantee them to NOT be DOA and to match test results on any Amplitrex AT1000 using the same settings and test parameters. Please ask any and all questions before purchase, thanks for looking!

The Transcendent Sound SEOTL uses 16 of these.

Four Winged C Svetlana 6BM8 valves never used as new.

Match Tested Pair of 6550C Svetlana SEC Winged C Audio Receiver Power Vacuum Tubes Country of origin: Russia Model: Svetlana SEC winged C Manufacturer: Svetlana SEC Type: Power Plates: gray vented with copper rods and radiators Spacers: two with alignment tabs Getter frames: dual solid saucers Getter flash: top Glass: clear Base type: Octal 8 pin with a metal base collar Construction: same configuration Condition: excellent Usage estimate: minimal Cartons: NA Quantity: 2 Please review the photos for more detail Excellent strong balanced NOS test results for Gm / bias: Gm: 6.8 with bias ~50.0 mA Gm: 6.4 with bias ~47.5 mA For Gm, 3.9 is the suggested minimum value No shorts detected For reference we use a calibrated Triplett 3444A Tester Compatibility: Suitable for audio preamplification and vintage tube-based equipment ideal for use in tube pre-amplifiers and audio recording equipment The tubes will be carefully packed to ensure safe shipping Estimated delivery time within the USA is 3 to 7 business days Standard shipping service is US Postal 1st class Shipping is combined when applicable Please feel free to contact us if you require any additional information

Four Winged C Svetlana 6BM8 valves never used as new.

Heres one of those rather good Svetlana black winged C EF86 that we import from Ukraine. Well you gotta help out, eh?This one is in very good condition. Its testing quite strong on the AVO with emission figures of 165% and a gm figure of 117%...which is certainly a muscle tube, as my tekky puts it.We give these EF86 types a good burn-in before even testing them to eliminate the brand new microphonics that occasionally plague them when brand spanking new. As this burn-in occurs in a spare Mullard 5-20 amplifier we can listen to it for quality of audio improvement over the first 24 hours or so.......These arrive bulk packed by my supplier in Kyiv (i.e. no boxes...) so we put em in quality white card individual shipping cartons. All details are on the box.Please note: we retest every valve before dispatch and check for microphony. If any valve is still lively because of this slight microphony, well post a better/better behaved one......

Heres one of those rather good Svetlana black winged C EF86 that we import from Ukraine. Well you gotta help out, eh?This one is in very good condition. Its testing quite strong on the AVO with emission figures of 165% and a gm figure of 117%...which is certainly a muscle tube, as my tekky puts it.We give these EF86 types a good burn-in before even testing them to eliminate the brand new microphonics that occasionally plague them when brand spanking new. As this burn-in occurs in a spare Mullard 5-20 amplifier we can listen to it for quality of audio improvement over the first 24 hours or so.......These arrive bulk packed by my supplier in Kyiv (i.e. no boxes...) so we put em in quality white card individual shipping cartons. All details are on the box.Please note: we retest every valve before dispatch and check for microphony. If any valve is still lively because of this slight microphony, well post a better/better behaved one......