Adcom Preamp Chip needed

[zonk74]

Hello,
I'm a newbie here and am happy to be aboard. A friend of mine is helping me restore some vintage stereo equipment I recently acquired.
I have been searching for a chip for my Adcom Model GFP-565 Preamp.
Please see the attached image. It may be that the chip was made by someone else.
Any info you have would be most appreciated.
Thank you,

Matt

 

[rayma]

Who knows which 1990 Linear Technology IC that was, other than Walt Jung. It was specially selected for the Adcom preamp.
The circuit would have to be reverse engineered, and then a current, suitable IC selected.
If the original IC is not defective, it should not be replaced.

 

[anibal]

If you get the schematics (I am pretty sure you can find them online); then you can look for a "functional" replacement.

 

[Pars]

The schematics are available. The part you show (IC401) is Adcom 7A, Adcom part # IC00002181. If you look at this thread here, there is a cross-reference showing potential replacements: https://www.diyaudio.com/community/threads/adcom-opamp-semiconductor-replacements.339904/

I would agree with the sentiment of why are you replacing it? Opamps don't often go bad in my experience.

 

[jackinnj]

They are all Linear Technology chips -- LLTC now owned by Analog Devices. (I have two GFP-565's).

 

[mlloyd1]

I also question why replace it if it's working?
But, if it has failed or if you just HAVE to tinker with it, replace with an LT1022 and be happy. Or an LT1122 if you have extra $$ just begging to leave your pocket.

 

[zonk74]

The schematics are available. The part you show (IC401) is Adcom 7A, Adcom part # IC00002181. If you look at this thread here, there is a cross-reference showing potential replacements: https://www.diyaudio.com/community/threads/adcom-opamp-semiconductor-replacements.339904/

I would agree with the sentiment of why are you replacing it? Opamps don't often go bad in my experience.

Thank you all for the information! This is great stuff. The IC is defective and needs to be replaced.