This is a little confusing. You are calling one of the tubes a rectifier. Why? Is it wired up as such? A 6AQ5 is a small power tube (similar to 6BQ5). An EBC90 is a triode with 2 diodes, so nothing like a 6AQ5. Neither of these is a rectifier.
An ECC85 (6AT6) is a double triode. Just because it can be used for VHF doesn't mean it has to be.
If this is a really old amp, they may have used tubes that were common at the time. Or it could have been a useable sub for some tube that is no longer available. Without a schematic it is pretty much guesswork.