In a Twitter conversation between Oliver Heldens and Deadmau5, Deadmau5 states he's using the Eventide H4000. The conversation follows:

Heldens: "I wish I'd could make my mix sound like yours. At the sound checks when they play ur stuff I'm like damnn"

Deadmau5: "@OliverHeldens just get a neve MBP and you're all set."

Heldens: "@deadmau5 ok will check it out! And what reverbs do u use? I feel ur reverbs have to do a lot with it as well?"

Deadmau5: "@OliverHeldens still using the eventide H4000."

An Eventide DSP4000 UltraHarmonizer is used by Steve Vai in his studio setup.

On his SoundCloud's account comments, another item that Richard David James mentions as gear that he uses is the Eventide DSP4000: "Really inspired me, thanks Tom, he gave me some of his patches, awesome stuff, wouldn’t want to use them of course, they are his. He made some synths on them which was some great lateral thinking at the time. Never rinsed my DSP4000 anywhere near as much as he did but I’ve been recently been giving the 8000 a REALLY hard time with the Cirklon! inspired greatly by Tom."

This is a picture of the rack John used for the 2002 World Tourbulence tour. Among the various units there's an Eventide DSP7000 Ultra Harmonizer (second from top to bottom). Confirmation of this being John's rack can be found in this diagram from Guitar Geek and at :15s in this video.

This effects processor was sold on Billy Corgan’s official Reverb.com shop.

Used for "synth-like reverb" of the electric guitar on Only by the Night, as stated by producer Jacquire King in this December 2008 Sound on Sound interview.

"We had five or six guitar amplifiers available for each guitar, and again, we picked the ones that were most appropriate for the song. Angelo and I would listen to the guitar parts and mix and match amplifiers. Sometimes we'd put reverb on one amp and a delay on another, or effect pedals on both. We had all kinds of combinations, although we kept it to two amplifiers per performance for each player. I'd put an SM57 in front of one amp and a U67 in front of the other. The guitars went through API mic pres, an API 550A EQ, and I also used some APSI parametric EQs. Occasionally I'd put an 1176 in the signal chain, but in general I don't use much compression on distorted electric guitars going to tape, because there's not a lot of dynamic range to them as it is. The synth–like reverb you can hear on the guitar was done at Blackbird on an Eventide DSP4000 and added during the transfer to Pro Tools.

(...) **Guitars: **Massenburg DesignWorks EQ, Sound Toys Echoboy, Cooper Time Cube, Digidesign delay, Audio Ease Altiverb

(...) "I also used an Echoboy for delay on certain sections, like in the choruses. There was a little bit of bus compression on the guitars and a little bit of EQ, all very minor stuff, because I had already recorded what I wanted. The only radical EQ is on the Cooper Time Cube delay, which I described above, and which I applied to Caleb's guitar. I took out everything below 861Hz to get rid of the darker tone that was obscuring the source tone a bit. There's also a bit of Digirack delay on Caleb's guitar, to give it a bit more dimension by panning it to the other side than the track itself."

Tom Rowlands, of Chemical Brothers fame, working in his studio. Just check out the complete list of this synthesizer nerd … an instant daydream … and also explains the original sounds on their records!

Used for the "synth-like reverb" on the electric guitar of Only by the Night, as stated by producer Jacquire King in this December 2008 Sound on Sound interview.

"We had five or six guitar amplifiers available for each guitar, and again, we picked the ones that were most appropriate for the song. Angelo and I would listen to the guitar parts and mix and match amplifiers. Sometimes we'd put reverb on one amp and a delay on another, or effect pedals on both. We had all kinds of combinations, although we kept it to two amplifiers per performance for each player. I'd put an SM57 in front of one amp and a U67 in front of the other. The guitars went through API mic pres, an API 550A EQ, and I also used some APSI parametric EQs. Occasionally I'd put an 1176 in the signal chain, but in general I don't use much compression on distorted electric guitars going to tape, because there's not a lot of dynamic range to them as it is. The synth–like reverb you can hear on the guitar was done at Blackbird on an Eventide DSP4000 and added during the transfer to Pro Tools."

"...I bought the DSP4000, and I'm still finding new things to do with that and with the Orville," says Tom, in this article.

"...The item can be seen 2:37 into this video..."

"I've got an old Eventide DSP 4000"

You can see 2 of them at 1:06