Where are you located? There are a number of Yamaha amps and units of that era that have knobs that should fit. The PC2002, P2100, P2050 etc. have similar knobs. Look for a parts unit that may be close to you. There's one on Ebay here in Burbank that's decently cheap but shipping to you may add a lot. Little known but I think the F1030 and F1040 active crossover filter networks also have similar knobs although I can't say for certain without checking the part numbers in the service manuals of both units.