Those things have eight tubes in them that should be tested at least. Buying a new set may be easier and will give you more of a guarantee that you are getting the most out of it, since it is more than 30 years old now. I heard a restored Mac1500 that sounded great but that is quite a different design than the 1700.
Hooking speakers in parallel on a 40W amp could be a real problem - I don't recommend it. Your speakers may have a low impedance to begin with which would overstress your amp.
I think it would be worth new tubes at least. Check to see if any of the caps have leaked at the base (brown goo). They may need replacing too. That said, I have seen several really old Mcs that really needed nothing done to them. It is up to you. Good luck!
Hooking speakers in parallel on a 40W amp could be a real problem - I don't recommend it. Your speakers may have a low impedance to begin with which would overstress your amp.
I think it would be worth new tubes at least. Check to see if any of the caps have leaked at the base (brown goo). They may need replacing too. That said, I have seen several really old Mcs that really needed nothing done to them. It is up to you. Good luck!