Regarding the Kustom IIB head & 115 cabinet: It is a 60 watt RMS amp into a 8 ohm speaker cabinet. The cabinet came stock with a 15" 8 ohm CTS speaker.
pleat
Could a speaker upgrade on this make a significant difference? I saw a photo of one online where someone had put a JBL d140f in it.
And if I upgraded the speaker, could I, at some point in the future, use another head with it, such as a 150 or 250?