Kurt Cobain

Starting at 1:04, Nardwuar asks Kurt about using an Echoplex, To which Kurt replies "I have one", though it is unknown if it is on any recordings that have been released, and it was likely not used live.

A Space Echo can be seen on top of kurt's speaker cabinet during this show. At around 17 minutes in he plays about with the self oscilation while dave's broken drum is repaired.

Used for vocals on Nevermind, as stated by producer Butch Vig in this March 1997 Sound on Sound interview.

Utilising a Neumann U67 and an LA2A, most of Cobain's vocals were recorded in the small Studio B at Sound City and ran straight to tape. The results alternate between a smooth, compressed, phasey sound and one of extreme dryness when the voice sits alone, yet minimal effects were employed. "Kurt really had an amazing voice," confirms the producer. "He could scream and it would have this great rasp and tone to it, and yet he could also bring it down really quiet and sound so world-weary and exhausted and intimate. It's hard to put your finger on it, but not many artists have that kind of voice or persona. Kurt had this brilliant pop sensibility in terms of melodic structure and phrasing, and yet he loved the attitude of punk, and those are the two things that collided and made Nirvana so special.

"In the studio I used a fair amount of compression on the vocals so that I could control his dynamics, and I also got Kurt to do some double-tracking. I'm a big fan of doubling, particularly on choruses, so he did that quite a bit on the record and that's part of what the sound is. Andy Wallace, the mix engineer, had a little bit of tight slap echo -- almost a double echo -- on a couple of the songs, and he also used a little bit of reverb and so on, but for the most part the vocals were left fairly dry. That really was the approach that the band and myself wanted to take. We didn't want to have it too washed out with reverb or echo, and it was the same with the drums and the guitars; we wanted everything to be fairly dry and in your face.

In this picture you can see... Kurt's Guitar Rack for the 01/25/92 Big Day Out, Sydney, Australia.

From top to bottom...

1) Samson BR-3 Wireless Unit. 2) Mesa Boogie Studio Preamp. 3) 2 Space Blank Rack Panel with Guitar Picks stuck to it. 4) Carver PM-1200 Poweramp. 5) Crest Audio 4801 Poweramp.

A dbx 160XT is used on Kurt Cobain's vocal and spare vocal, in line with a Klark Teknik DN300 on each channel.

In this YouTube video at 0:40, The drummer from Nirvana (and also the GOAT of rock) Dave Grohl mentions that this is the Neve 8028 mixing console Nirvana recorded on. Recording engineer Butch Vig would of used the Neve 8028 mixing console at Sound City studios to record Kurt Cobain on Nirvana's second album Nevermind.

Kurt Cobain, the renowned guitarist and singer, explicitly mentioned owning and utilizing an Echoplex in an interview hosted by Nardwuar the Human Serviette, which took place on January 4, 1994. During this discussion, at a specific timestamp (1:01), Cobain can be heard talking about owning and using an Echoplex. This information is further substantiated by additional confirmation from a dedicated gear website: https://whatgear.com/pro/kurt-cobain/maestro-echoplex

Citing a "[p]ersonal communication" with Earnie Bailey, Caio Leme of LiveNIRVANA.com reports that Cobain used a Countryman Type 85 DI for live shows starting on October 26, 1993 (at MECCA Auditorium, Milwaukee, Wisconsin), including for Nirvana's MTV Unplugged show. Leme includes this photograph taken by Kevin Mazur of Cobain at the MECCA Auditorium show.

Typically placed before the effects, with one output connected to them and then balanced out to the desk. On Unplugged, it was used after the effects.