I got myself a beautifull SA-7500 amplifier, still in good working condition. I've cleaned all the pots and switches ultrasonicly. Also I've recapped all the boards, replaced the 2SC1451 transitors with the KSC3503, the 2SA725/2SA726 with KSA992 and the 2SC1312/2SC1313 with KSC1845 because I've read they can become trouble. But now I found two 2SK34 n-fets (Q1 and Q2) on the Control Amplifier Board. According to the Jaeger Elektronik table the 2SK34 is listed as (LF,Uni, 30V, Idss=0.3...12mA, Up=0.3...6V) and a possible replacement is BF245 (NF/HF...VHF, 30V, Idss>2mA, Up<8V) or 2SK381 (Uni,50V, Idss>0.3mA, Up<6V). But when I search the forums here I find that the 2SK34 is 50V. Is it possible to use the BF245 replacement in this situation (they are easy to get here in Europe)? I can't read schematics so I don't know whats the purpose is of the fet in the Control Amplifier.