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.

On his website, electronics tech to the stars of the 70s, Pete Cornish attests that "My first commission from Queen was to eliminate the ground loop hum caused by the interconnection of 3 X Vox AC30 Amps and 2 X modified Echoplex EP3 Delays. In January 1972 I designed and built special circuitry to isolate the amps and echoes, which successfully eliminated all the hum problems. This system was used for their first and subsequent tours up until 1982, also the recording of their albums during this period.

By January 1976 Brian May was using 9 X AC30 amps on stage and the same 2 Echoplex EP3 Delays (see photo 9 X AC30 + EP3s) – this required an enlarged Routing System which I designed and built. Despite the large number of Vox AC30's then in use my system successfully eliminated all Ground Loop hum and noise."

So Brian was using modified solid-state Echoplex tape delays for his huge wet/dry/wet echo sound from at least '72 into '76.

Used on “I’m Bad, I’m Nationwide”, as recalled by Gibbons in this December 3, 2009 Guitar World interview. It is also visible as a label on Gibbons' pedal switcher in Fuzz: The Sound That Revolutionized the World at 1:20:18.

“I’m Bad, I’m Nationwide”

Deguello (1979)

“We wrote this about the great Texas bluesman Joey Long, a Gulf Coast lead-guitar picker who appeared on a great number of wonderful records by the likes of Slim Harpo and Barbara Lynn. He played on Lynn’s great hit record ‘We Got a Good Thing Going,’ which was covered by the Stones, and which was really one of the important recordings that shaped my understanding of where it was I wanted to go with my life. It was good. And so was he.

“Joey loaned me a multistringed mandolin-like instrument from Parral, Mexico, and I put it to good use on ‘Nationwide.’ If you listen closely, you can hear close-miked mandolin-sounding rhythm accompaniment. The lead track was played on a custom-made, half-size, real short-scaled guitar tuned to G. It was actually standard tuning cranked up a minor third, which remained quite playable thanks to the guitar’s short scale.

“The song’s tail end alternates between three distinct effects created by two pedals: an Echoplex doubler and a Maestro octave box alternating every third bar between having the octave up and the octave down. The song also contains some Hohner Clavinet, which was owned by one of our famous Memphis pals, Carlos De Marlos. It’s such an interesting sound that it ignited Dusty’s [Hill, bassist] interest in learning some keyboard skills, and it was he who subsequently handled all the tickling of the ivories.”

In the Gibson article "Revelation: The Tone Secrets of Randy Rhoads," it is noted that Randy Rhoads incorporated the Maestro Echoplex into his rig to enhance and thicken his sound.

"Lead is just what I always was. A 50 or 100 watt Marshall, a Echoplex and a BK Butler Tube Driver. Same thing for many years."

This Guitar World interview says, "Across the top panel are switches for, variously, a Mu-Tron octave divider; an old, AC-powered MXR analog delay; a Boss Flanger in a “blue, cast-metal box”; and an Echoplex."

two Echoplex(s) side y side, far left, probably 1976 All the World's a Stage tour.The Mini Moog appeared (not yet recorded) on stage, and the red double-neck had not been damaged by the falling speaker horn at the Blue Oyster Cult gig at the Nassau Coliseum Jan, 1978.

Here's an excerpt from Lifeson's great cover interview in Guitar Player, June 1980.

Which guitars did you use on Rush's first LP, Rush?

I used the 335 and a rented Rickenbacker 12-string. That's it for guitars. I played them through my Marshall 50 with a 4-12 cabinet, and I used a Maestro phase shifter, a Cry Baby wah-wah, and an Echoplex.

Did you go through a guitar-buying phase at that time?

I sure did. Some I bought because I wanted them, and others I bought to replace damaged instruments. We were doing a gig with Blue Oyster Cult at the Nassau Coliseum in Long Island, New York, a few years ago, and the double-neck cherry-finish Gibson I had bought in Nashville shortly before that got injured. The rigging wasn't done properly, and a long-throw horn speaker fell right on top of it, shearing the bridges off and taking huge chunks out of the body. Not only that, but the horn also fell on my 335 and gouged its neck out. That really hurt. The 335 had been with me for ten years; the neck was worn down just right, the finish was worn down from playing thousands of bars and high school dances, and I was proud of it. After that I said, "This guitar is staying home. I'm not taking any further chances with it."

What did you replace those guitars with?

I got a white Gibson EDS-1275 double-neck to replace the cherry-finish one, and I had a Gibson ES-355 made in 1976 with a cream-colored custom finish. That's my main guitar now.

What type of wah-wah do you use? " I have a Mu-tron and the Oberheim VCF (voltage control filter). I've got an example of that on this new album (Zoot Allures). I'm starting to use some Echoplex now, which I've generally avoided in the past. " - Guitar Player Magazine 1977, written down on the Frank Zappa Wiki "Wiki Jawaka"

In this interview, Wes Borland talks about the Limp Bizkit album Gold Cobra. He describes the "amp and effects chain that [he] used on My Way," saying, "A Maestro solid-state Echoplex and an Ibanez flanger pedal that has a setting called 'whacked'…"

"I have about five Echoplexes, all of which have unique qualities"

Mentioned in this March 1983 Musician article.

Ever loyal to their roots, both Petty and Campbell play through very cool looking Vox Super Beatle amps, jazzed up with Echoplex and MXR Dyna Comp.

In the very early days of Police, Andy was using just the MXR Phase 90 pedal, and a reverb. As he became more successful, he got himself the Pete Cornish pedalboard, which had all kinds of effects programmed into it, including Mutron Envelope filter, wah wahs, fuzz boxes and distortions like EHX Muff Fuzz and Distortion+, MXR Dyna Comp Compressor, Phase 90 and others. He also used the Roland GR-300 Guitar Synthesizer.

But, the two effects which were really the key to the Andy’s sound with the Police are the Maestro Echoplex tape delay, and the Electro Harmonix Electric Mistress.