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Adcom GFA-555 modified

Here is a clean Adcom GFA-555 amplifier. Designed by Nelson Pass and modified by Chris Hoppe. I have had this amp for a number of years and it has performed well. Late last year I contacted Chris Hoppe about modifying and cleaning the amp up. Please visit his website for more information www.hoppesbrain.com

Cosmetically is a 7-8. Electrically a 9. Improved power supply layout with new capacitors that now include bleeder resistors. AC snubber capacitors have been added to the new larger 50A bridge rectifiers, which have been moved to the chassis for better cooling. New matched transistors in the input stage, along with bypass caps added to the input board. Drive transistors have been replaced with ones having greater voltage headroom. Output transistors remain as the original Toshiba 2SD424/554. Circuit boards have been cleaned and solder joints reflowed. New power switch along with a spark supressor capacitor. Sealed Bournes bias trim pots, Dale resistors throughout replace the old sand-cast resistors. New Panasonic and Nichicon capacitors have been installed. A new chassis IEC plug, which the original did not have has been installed. New gold plated RCA and binding posts add the finishing touches.

$750plus shipping


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