op amp upgrades for adcom gtp 500 11?

[crippledchicken]

hi i'm new here and hello to everyone. i just purchased this preamp and due to the age, i thought i might need to replace the op amps and figured i might as well upgrade while i'm at it. any suggestions anyone? 2 of them say adcom 7a-9007 and 2 say adcom 5f-9013. any help would be appreaciated. thanks, crippledchicken

 

[paulb]

Hi. Do you access to a service manual? How old is the preamp? There are lots of good opamps available, but depending on the age of the unit you may not notice a difference.
I suggest you get at least a schematic diagram before trying the substitutes.

 

[crippledchicken]

hi paulb, thanks for the comeback, i just got this off of ebay seems to be a decent preamp/tuner. i replaced the 1n4003 1amp 200v. bridge diodes with 4 amp stealth diodes from fairchild, doubled ps capacitance and bypassed with good results. on the main board it says 1989 date of manufacture. with pin#8 v+ and pin#4 v- i assume they are duals and the rest of the pins are standard configuration but want to be sure! don't need any fire works he he. i will do a little more searching and maybe i will run on to someone who is familiar with unit and has upgraded them. if not, i'll check into a schematic thanks and merry christmas to you and yours. crippledchicken