EDIT: it turns out the 2SC1917 were fine, the culprit was TR671 / 672 (2SC1213, replaced with 2SC945) Hello Yamaha people ! I've fully restored my nice CR-620, it's all working very nicely apart from a hiss in one channel. Volume does NOT affect the hiss, but the treble control does, as do all other tone controls and filters. The only transistors between volume and treble control are TR601 - 602 - 603 - 604. They are 2SC1917, there are a few in this receiver. What can I use as a modern substitution ? I searched AK and hardly found any reference to these transistors... so I need some help from you specialists I have some KSC945, KSC1845 and 2SC3503...are any a good candidate ? Thank you !