Yes you can fillet braze with silver, I made a few that way and know of other framebuilders who have done lots. There are some silver fillers that do make a decent small fillet and have a low enough melting point for 753. There are potential pitfalls, but with good joint design and preparation, and proper brazing technique, the joint can be stronger than the parent metal.
The so-called "nickel-silvers" such as the All-State #11 mentioned by e-Richie are not suitable for 753 though, as they have a high melting point. Strangely, there is NO silver in nickel-silver; I don't know how they get away with calling it that, but that's the industry-standard term, at least in the US.
Kinda like how the welding/brazing business often calls brass fillet brazing "bronze welding", though it's not bronze and it's not welding. (Brass is primarily copper+zinc; bronze primarily copper+tin; the latter is not used in brazing that I know of.)
Not that either one of these examples is *wrong* - if they're the standard industry terms then they're just jargon, which operates under different rules than regular language. I just don't like it when they throw away useful distinctions. When you use bronze to mean brass, what word do you now use for what used to be known as bronze? Whoops, way off topic.
Mark Bulgier
Seattle, Wa
USA