Soundhouse is right about your RX-505 being on it's last legs. However, you can have it gone through by a reliable
Nak expert. His name is Willy Hermann. You can contact him at firstname.lastname@example.org. Believe me, he will have
it working and sounding better than new. By coincidence,
I'm listening to my RX-505 through my tube Stax headphones
and I can assure you that the RX-505 is worth the expense.
Willy rebuilt my CR-7A and this RX-505, and he now has my ZX-9 in for a tune-up. He'll do it right. Tell him I sent you! You won't regret it.