I have obtained a 1980s Marshall 1931 cabinet with a Fane speaker, which is rated at 75 Watts, open back. Can I put in a speaker that can handle bass and guitar rating at about 100 Watts? If so, which one is the best and can I put on a closed back?
Dave Crawley via email
SOS Editor In Chief Paul White replies: There's no mechanical reason not to do this, but be aware that if you put a closed back on the box, the sound will change and you'll probably lose some low end due to the relatively small size of the cabinet.
This may be OK for guitar — you'll just have to judge that for yourself — but it is unlikely to have enough tonal depth for bass. If you really need to handle bass, it would be better to build or buy a new cabinet to suit your new speaker, and Fane probably have design notes you can use to see how big this would need to be.