I have got some real joy with 5751 series. GE black plated extend well for both highs and bass and had a lot of life . They are cheap and the sound good I also tried some raytheon CK5751 but they a bit too transparent for me that.
Two cheap tubes with good sonic characters. Randy had the 5751 series on his old site listed as vintage sounding if that is of any help
Two cheap tubes with good sonic characters. Randy had the 5751 series on his old site listed as vintage sounding if that is of any help