Need pics of the tops and scratches or gouges. Having said that, consider steam heating the scratched veneer to raise up the grain of the scratches until they are level or just above the rest of the surface.
To do that, you need a good clothes iron, a few cotton wash cloths, and patience. Set the iron to a cotton setting, moisten (but not dripping wet) the towel and place over the scratch in question. Then lay/press the iron over the towel and hold for 10-15 seconds or so. Don't leave for any excessive time as you could burn the veneer, especially if the towel dries out. Done correctly, the compressed wood fibers in the scratch / gouges will absorb the steam, swell, and raise up. Multiple short passes are best to control the heating IME. Once you get the entire surface pretty level, a light block or orbital sanding is all you need to even the surface out. Be sure to let the entire veneer dry out for a day or two before applying any finish as the scratched areas may take up any stains differently than the surround surface.
After a good wipedown, you could use Howard RAF and then a light wax with Howard Feed N Wax, or the Watco Danish oil method, or the tried and true JBL Boiled linseed oil.
JBL VIntage speakers have pretty robust veneers that can be sanded, carefully. Most typical home veneer damage on JBL's will come out nicely with care. If really too far gone, most JBL's are easily reveneered.
