Hi ihcho,
I bought a used SA103 here on Audiogon a few years ago. It arrived with a noisy right channel, so I contacted the Plinius importer for repairs, who put me in touch with Vince. Vince told me about the suite of mods he had developed over years of working with these amps (he was the original importer of the brand), called the Galbo Ultimate Upgrade, or something similar. It entailed replacing many of the caps and resistors. I think it was $1,500.
Not only did this upgrade fix my noisy channel, it substantially improved the amp, which I found very good but a little bottom-heavy before, and a little lacking in HF extension. After the modes, it was more balanced, transparent, and extended on top and bottom, while retaining the liquid mids I liked about it to begin with. Ralph actually did the work.
Earlier this year, one channel stopped switching into Class A, so I contacted Vince, who told me he’d sold the biz to Ralph. Ralph fixed the problem (a bad relay, unrelated to the earlier mods). He also upgraded the power supply with new and much better caps, something that was not part of the first Upgrade. This new mod further deepened and tightened the bass, further extended the highs, and gave the overall sound more coherence. I’m very happy with the improvements.
I hope this helps.
Bill