Wow! Adcom has released the “new” GFA-555SE. They call it “A Classic Reborn” - who can argue.


Modification Strategy: Our venerable LX mod for your Adcom amplifier has changes in feedback circuitry which improves bandwidth, dynamic range and bass solidity/power. The bias circuit uses a new and better bypass capacitor with an added high quality bypass capacitor. Input and output filters are improved with far better parts. Some critical resistors are upgraded. Each small-value (picofarad) high frequency stabilizing capacitor is optimized for audio quality.  Each power supply capacitor has an added bypass capacitor. Elite and higher models have superb power rectifiers in the main power supply. We have found the finest soft-recovery diodes superior in naturalness and dynamics. 


The Sound: LX is much more natural, sweet and liquid. Soundstage is much more open. Imaging from top to bottom is more predictable, i.e. instruments come from stage locations that seem more accurately positioned. Gone is the brightness, etched quality and bass inaccuracies. Perceived dynamic range soars! The Elite version is even more refined/defined with solid bass extension and silky extended high-end detail, a definite improvement in resolution and definition. The mids have superior timbre, texture, clarity and musical naturalness. Highs are more natural and clear.



We no longer support all Adcom power amps. The newer power mosfet amps, GFA-5500/5800/5802 plus several others and multi-channel amps are not serviced.




LX Mod

LX mods are for all the earlier classic stereo or mono Adcom amplifiers, including all “535”, “545”, "555", "585", “565", etc. 

$399 installed for early model Adcom stereo amps, except for the following : GFA-565 LX mod is $599/mono pr



LX Elite Mod

$599 installed for all early model Adcom stereo amps, other items listed below – for GFA-565 $799/pr



LX Mini-Platinum Mod

While you could apply this to the standard LX mod it clearly makes the most sense to add it to the ELITE version. A mix of Takman CF and highest quality Dale resistors, in strategic locations, offers superior naturalness and clarity. Some added "double bypass" caps are used in critical locations. Add this upgrade to an ELITE mod for even more natural sound. Add $200 to stereo ELITE mods, $300 to ELITE mono pair pricing.


See power supply options by visiting these pages - Amp Options and PS-200

See our "Connector" page for hi-quality RCA connectors and binding posts that we can install for you!


Adcom Amplifier Modifications