This is from the 1.7 manual:
The terminal plate states a maximum fuse value of 4 amps Type 3AG ("normal" or "fast blow"). The bass section
does not require fusing protection. This fuse value should never be increased or bypassed. Do not use slow-blow
fuses. BURNED OUT TWEETERS ARE NOT COVERED UNDER THE WARRANTY.
The terminal plate states a maximum fuse value of 4 amps Type 3AG ("normal" or "fast blow"). The bass section
does not require fusing protection. This fuse value should never be increased or bypassed. Do not use slow-blow
fuses. BURNED OUT TWEETERS ARE NOT COVERED UNDER THE WARRANTY.