Hello dear OMs, thanks a lot for all the replies in such short time !... I got lots of hints and links regarding compatibility of CF300, BF981, BF988, CF739, CF930... The first preamp (2m Landwehr) is running now again using a BF981 - great! Thanks all again, Happy New Year !!! hope to hear you next year vy 73 - Tor, DJ8MS !...