time delay relay?

Hello, This is probably really simple but I'm not very good at this and can't seem to figure it out. I'm trying to wire up a Time Delay Relay that stays on for 20 seconds then cuts power. I believe all you need to do something like this is the correct resistor and capacitor for the delay and connect that to a relay. I'm not sure if I need to use an automotive relay, but I have a few miniature relays lying around (Zettler AZ733, for example) I found this: https://www.the12volt.com/installbay/forum_posts.asp~TID~124243 and tried to wire up the second diagram there - seemed simple enough, but I can't seem to get it to do anything. When I monitor the capacitor, I can see it charging, but when I hook up one the relays that I have, the charge drops dead. Is it because I'm using the wrong relay? I figured relays are all of the same type of operation, but maybe I'm wrong. Thanks in advance

In the link you posted, that is a delay on setup. From what I am reading from your description, you need something that is going to remain on after power is removed from the coil. Is this correct?

I may have described it wrong - what I would need is a setup that would do the delay, flip the relay and shut off once power is removed. I have an amp connected to a CarPC I'm building and I'm trying to get rid of a thump that happens about 20 seconds in when OS loads. It has a mute pin and I figured I can get a 5 prong relay to hold that pin down for the 20 some odd seconds and then unmute it. Alternatively, I can use the relay to just delay power to the amp and it should give me the same result. I hope this clears it up !

Alright, I've got the second schematic working using a 20000uf capacitor, 100ohm resistor and 12v relay with about a 1 second delay - Aside from getting a giant cap, is there any way I can increase this delay to around 20 seconds?

It will take a cap and a transistor. Give me a minute to put something together.