This is a picture of the rack John used for the 2002 World Tourbulence tour. Among the various units there are two TC Electronic 2290 delay units (third and forth from bottom to top). Confirmation of this being John's rack can be found in [this diagram from *Guitar Geek*](http://www.guitargeek.com/john-petrucci-dream-theater-guitar-rig-and-gear-setup-2002/) and [at :15s in this video](http://youtu.be/4yUUCRJGdko).more
"I used the effects loop of a TC 2290 that bypassed the harmonizer’s return, but not the send to it. Then when I wanted to sound backwards, I could kick the effect in instantly," says Henry Kaiser, in [this article](http://www.premierguitar.com/articles/Henry_Kaisers_5_Essential_Effects), by Premier Guitar.more
In [this interview](http://www.musicplayers.com/features/guitars/2007/0407_Steve_Rothery.php), Steve Rothery says, "I decided on the Marbles album to incorporate one of my 2290s, so that does most of the switching because it’s instantaneous with patch changes, and it’s a great sounding unit anyway, which also meant I could use other things in the loops for that."
The 2290 is among many effects used by Robert per this [archived version](https://web.archive.org/web/20040213203727/http://archive.guitarplayer.com/archive/artists/thecure.shtml) of an April 2000 edition of *Guitar World* magazine. *Sound on Sound* also lists this as part of The Cure's gear set up [here](http://www.soundonsound.com/sos/1996_articles/jun96/thecure.html).more