There is a lot of potential for turning this into a guitar amp rather than a bass amp. adding bypass caps on the input stages gets you most of the way there.
A warm welcome to tube amp modding fans and those interested in hi-fi audio! Readers of Kevin O'Connor'sThe Ultimate Tone (TUT) book series form a part of our population. Kevin O'Connor is the creator of the popular Power Scaling methodology for amplifiers.
Please remember these three principles: respect, sharing, community.