Matched pair of double triodes 6N1P-VI (6H1П-BИ). This version of tube from the 6N1P family has improved mechanical strength and was designed for pulse operation. It is also typical with much tighter tolerances. 6N1P-VI tubes are direct replacement for the chinese 6N1 and they do offer better performance. It may be also used as a replacement for the ECC88/6DJ8/6922 tubes, but you have to be careful, because there are some important differences. The 6N1P-VI's are drawing considerably more heater current: about 600 mA, comparing to the ECC88/6922/6DJ8 tubes, where it is about 365 mA. In some cases a direct replacement without any discussion with the manufacturer may end up with damaging of your equipment. Please discuss this with the manufacturer of the equipment. Manufacturer: Nevz, Novosibirsk. Year of production: 1978.