Gairebé tots tenen fils escalfadors que poden ser usats en series ( 12,6V a 150mA ) o paral·lel ( 6,3V a 300mA ). Algunes d'aquestes vàlvules són intercanviables entre si, com la 12AT7, 12AU7, 12AY7 i la 12AV7. Aquests doble-tríodes varien en la quantitat de guany que poden produir, sent la 12AX7 de les que produeix més guany. D'altres ... www.jj-electronic.sk 5 ECC81 A. F. DOUBLETRIODE Base: NOVAL U f = 6,3 or 12,6 V I f = 300 or 150 mA Typical characteristic: U a = 250 V I a = 10 mA U g = -2 V S = 5,5 mA/V µ =60 R i =11 kΩ Limiting values: U a = 300 V W a =2,5 W I k = 15 mA U g = -50 V U k/f = 90 V R g =1 MΩ Dimension and connections: 4 ECC81 - 12AT7, 6201 Customer Reviews Great All Around Tube Review by David S. I purchased a bunch of these from Doug years ago, and some more recently, and they are just great all around tubes.

A high-gain 12AX7 really got the power amp sounding too smooth for my tastes, especially in the case of a smooth-sounding tube (i.e. Mullard RI). With a JJ or Amperex 12AU7--which both sound about the same in the PI, by the way--the tone was a lot crunchier, a bit tighter, and definitely more clear. I also got a bit more headroom. electron Tube Data sheets - 6. ... Data sheet; 6J6 Brimar tt 6J6.pdf (99646 bytes) 6J6A ... JJ P 6L6GC.pdf (198340 bytes)