ADCOM GFA-555 Amplifier Upgrade

[bigskyaudio]

Our audio shop has closed due to retirement and I would like to share our mod for the ADCOM GFA-555 power amplifier. I hope that this will help some of you who would like a little better sound quality but the mod will improve clarity first and foremost.

 

[KSC1845F]

Congrats on the retirement. I bought up the 2SC2240BL stock you were offering on ebay 🙂

 

[bigskyaudio]

Thank you for your kind retirement wishes!

 

[invaderzim]

congrats on the retirement and that is very kind of you to think of sharing the information.

 

[K-amps]

Congrats on the retirement, thanks for helping!

 

[audilux550]

Hi folks. I am also interested in adcom555s mods for a better clarity and SQ. But seems like many folks just read this thread and moved on without sharing if they perceived any difference in SQ after following the procedure.

 

[audilux550]

Anyone noticed difference in sonics

 

[Mikerodrig27]

Cool! I just picked up a Adcom GFA-550 original. I am going to go through it using your original upgrade document. I did your upgrade to my Adcom GFP-565 and it did wonders.

Thanks again!

 

[Mikerodrig27]

Okay, $140 later, I have all of the parts ordered from Mouser. I had to substitute parts here and there. Dale Precision resistors, Silmic II caps. I skipped the optional stuff. That can go on the next order if needed. Everything came out to about $140 after tax and shipping.

Thanks again BigSkyAudio!