While many here have and would disagree with me, aside from the potential warranty issue I wouldn’t worry too much about substituting an audiophile-oriented fuse having a current rating 27% higher than the original. For two reasons:
1) There have been numerous reports here in recent years of various audiophile-oriented fuses blowing when they shouldn’t have. From at least 8 different members that I can recall in the case of SR fuse threads alone. Which suggests to me that the unspecified melting points of many of these fuses may be significantly lower than their current ratings would suggest. (Melting point is commonly specified by major manufacturers such as Littelfuse and Cooper Bussmann in terms of amperes-squared x seconds, but I don’t recall ever seeing such a spec being provided by a manufacturer of audiophile-oriented fuses).
I don’t recall previously seeing reports about false blows in the specific case of HiFi Tuning fuses, but as a member for whom I have great respect I certainly have zero doubt as to the veracity of Analogluvr’s statement.
2) Another reason for my relative lack of concern about the 27% rating increase is that it’s not an exact science. I would expect that the designer analyzes and/or measures the current draw of the component under worst case operating conditions, and also the magnitude and duration of the "inrush" current surge that occurs at turn-on, and chooses the current rating and melting point of the fuse by applying what seems to him or her to be a comfortable margin relative to those numbers. Another designer might very conceivably choose a somewhat different margin.
IMO. As I said, many others here have and would make reasonable arguments to the contrary.
Regards,
-- Al