Using sauce as a soup base I am wondering which, if any, prepared sauces would work as a soup base. After several experiments I have found that none of the many (mostly Asian) sauces I have on hand work for this (just an experiment folks-- I am not trying to live on sauce).  Is there a general property that makes a liquid (or powder) an effective soup base?  Is it just more intensely reduced?  Hopefully, it is not just a matter of salt.

I have noticed that in packages of ramen the soup base packet is tiny but packs a lot of flavor.  Recently I have gotten some ramen where the soup base is liquid in a tiny packet and that got me thinking about this.

Update: Based on an answer below I should add that my experiments showed that even a LOT of sauce still makes for an very weak soup.  The characteristic I am wondering about is how a tiny packet of liquid (much less than a teaspoon) can provide a strong flavor where say a 2 or 3 TABLEspoons of stir-fry, or other sauces make for a horribly weak soup for the same amount of liquid.
Very simply, all of them work. 

The major driver of what tastes good to you is expectations. If you are accustomed to eating soup with a certain taste, and expect it to taste that way, then any time you prepare the soup with something different, it won't taste good to you. 

But there is no rule to define that some liquids taste good as a soup base and others taste bad, universally. And without knowing how you like your soup, it is impossible to predict which ones you will like personally. 

Update In the edit you mention that it is the concentration that is wrong for you, not the flavour profile altogether. 

What gives the soup flavour is not the liquid part. In fact, the liquid in both sauces and commercially available "soup base" as well as fond, stock and other similar stuff is pure, tasteless water. The taste comes from whatever is dissolved in the water. 

Whatever you are using as a soup base seems to be just much more concentrated than the sauce. It is very probable indeed that one of the things which don't have enough concentration for your taste in the sauce is salt, another one is probably MSG. But also other flavour bearing compounds are probably provided in less concentration in the sauce. After all, the sauce is supposed to be poured over solid food, and shouldn't taste bad when you lick it off the food surface, it is at a concentration which doesn't taste too bad when it comes in contact with your tongue. The soup base is at a concentration which after dilution falls in the commonly acceptable range (but at a lower concentration than undiluted sauce).