If all the new caps are the same value as the old ones, then the old caps were shot, and this is how the circuit is supposed to sound.
If you changed the values, then who knows.....
If the values are the same, but you're not crazy about the bass response, look at lowering the value of the first coupling cap and / or the first cathode cap.
This is a Vox right?? Not really known for their thunderous bass response
Did you change anything else?