Description

SIEMENS MATCHED PAIR ECC81 PRE OWNED TUBE Ia1 Ia2 S1 S2 NR.42 results: 8.80 8.50 4.85 4.45 NR.44 results: 8.60 9.00 4.85 4.55 Ia 100%=10mA S 100%=5.5mA/V This parameters are measured at : UP = 250V Ug1 = -2V UH = 12.6V These tubes are tested in three ways : inserted into the test amplifier and listening to music for a few minutes; verifying vibration response and removing microphonic tubes; measuring the parameters using the tube tester, under 250Vplate / -2V g1 / 12.6V heater conditions; are accepted tubes with Ig1 <1 microA, 8-12mA anode current (typically 10 mA, below 8 mA are considered too weak), transconductance 4.4-6.6 mA / V (typical 5.5); we use high accuracy Russian tube tester L3-3, well calibrated; with the test amplifier being injected sine signal 1000Hz and visualizing the level and shape on the oscilloscope. After these tests are selected tubes with close parameters, that make matched pairs. The tubes was tested by profesional engineer. Please allow for the following shipping times: EU countries: 5-8 business days, on rare occasions a few days more USA: 10-15 business days, on rare occasions more South East Asia (Japan, Singapore, S. Korea, Hong Kong, Taiwan etc) 10 business days, on rare occasions more India, China, Russia, Kazakhstan, Pakistan, Indonesia, Malaysia, Thailand, Australia, South Africa etc: at least 15 business days, but frequently around 25 business days Please note that shipping cost is calculated at average. If you have any objections please contact me for a specific quotation.