I’m the original owner of a beloved SAE 2200 amp bought in 1977 that is still in use. In 2001 I paid the original designer James Bongioro to completely upgrade it. Every capacitor got replaced with poly & premium electrolytics. He replaced all the semiconductors (diodes, transistors) except the matched input transistors which he said were working well and had no better modern alternatives. The output power protection circuit was removed. And the final upgrade was his addition of an op amp servo bias circuit board that was not present in the original SAE design. He used an Ampzilla servo bias circuit board. Boy did he boost the bias voltage over the original factory set level, too! The unit now runs about 50% hotter (and sweeter) than it did all those years before 2001.
Recently I’ve added an Ayre AX-5 Twenty amp for daily use. But I still have the SAE 2200 hooked up. I’ve auditioned many solid state mid-high amps over the years and until I heard the Ayre, none were more musical than my upgraded SAE. Certainly nothing within an order of magnitude above the $400 paid to James for the upgrade.
James Bongiorno, a "pioneer of audio", passed on in 2013, sad to say. http://forum.audiogon.com/discussions/death-of-jim-bongiorno
Recently I’ve added an Ayre AX-5 Twenty amp for daily use. But I still have the SAE 2200 hooked up. I’ve auditioned many solid state mid-high amps over the years and until I heard the Ayre, none were more musical than my upgraded SAE. Certainly nothing within an order of magnitude above the $400 paid to James for the upgrade.
James Bongiorno, a "pioneer of audio", passed on in 2013, sad to say. http://forum.audiogon.com/discussions/death-of-jim-bongiorno