Need to add delay to a headphone jack

[Reticuli]

I need a cheap, effective means of adding delay to a headphone jack. This must be either built into a headphone amp or something I can put between a headphone amp and source jack. And again, the cheaper, the better... but it must work and not sound horrible. I'm not looking for echo, by the way. This will be purely a wet signal. The amount of delay should also be adjustable.

[Richi]

Simple delay on many guitar pedals maybe what you want to look at.