Technics SU-3500 some transistor replacement ??

[Robert2017]

Hi . I am going to replace 2SA720 and 2SC1318 in this Technics SU-3500 amp . The amp is working great but I have some background noise .

Based on another thread 2SA720 and 2SC1318 those definitely need to be replaced . I want to replace those with KSA1013 and KSC2383Y

Should I also replace the 2SA722 and 2SC1328 just as a caution ??

2SA722 and 2SC1328 are very hard to find and it seems there is no right replacement unless I buy the originals from Littlediode or other vintage store .

I used this amp for over 20 years . On diferent threads there are many examples of 2SA722 and 2SC1328 going bad .

Please check the photo . What should I do ??

 

[Robert2017]

to replace all 4 types is already to much but I will work on that
thanks

 

[avionic]

2SA722 and 2SC1328

KSA992 ---> 2SA722
KSC1845 ---> 2SC1328

 

[Robert2017]

I hope those KSA992 KSC1845 replacement parts will work like the originals ?.
Maybe I will get rid of that subtle background noise ?.
Also I hope there is no need to replace even more transistors .
I already did a lot inside this amp changing all transistors inside the main amplifiers plus some other more transistors besides the complete recapping .
Thanks a lot !!