David Howell Evans turns 50 on August 8. Known to everyone but his parents as (The) Edge, he has been U2’s guitarist and primary music writer for 35 years. Fitting of his nom-de-rock, Edge slices opinion among the guitar community. Some think Edge is too reliant on FX and technology. Many others acclaim him as one of rock guitar’s finest, a true innovator in a swamp of soundalikes.

Whichever way you cut it, it’s undeniable that Edge sounds like no other guitar player. He is the sound of his band. Without him, U2 wouldn’t sound like U2 at all.

Edge is a vintage guitar fan, yet he’s simultaneously a tech-head. He’s “the scientist” (Bono’s other nickname for him) and a “sonic genius” (Bono again). Edge is a Christian, yet he’s also an iconoclast who doesn’t “believe in rules”.

Here’s some wit and wisdom from a guitar enigma and his friends.

Happy birthday, “Dave.”

On the birth of Edge’s unique guitar style…

“I guess I was just sick of the white blues rock thing, which was just anathema”, Edge told Guitar magazine. “I always thought the whole 15 minute guitar solo was such a load of wank. I was attracted to people who really played the songs. But it’s the hardest thing – to have a really good song with interest and unique guitar playing”.

If the song isn’t their best, U2’s first single “Out Of Control” demonstrates Edge’s unique style arriving fully-formed ­– melodic, propulsive and harmonically ambiguous. The latter trait is key to Edge’s sound. He often uses two-note (root plus fifth) chords and steers away from fretting the third note of the scale, thus rendering the songs neither major key nor minor key.

“I like a ringing sound on guitar”, he told Musician magazine, “and most of my chords I find two strings and make them ring the same note, so it's almost like a 12-string sound. So for E I might play a B, E, E and B and make it ring. It works very well with the Gibson Explorer”.

On U2’s unique chemistry, a foursome unchanged in five decades.

“If I wasn’t in U2, I don’t know if I’d be a musician at all”, Edge told Guitar in 1995. “I’m not sure I’d want to be in any other band for a start, and the creative environment we have is so exciting and challenging, I can see us doing this for another 20 years no problem. But if I was out of this environment, I don’t know if I’d be interested enough to play music at all”.

On his expansive use of effects…

“I don’t see effects as an extension of the guitar, they’re part of it,” he told Guitar magazine. “In many ways, I play effects as much as I play the guitar. A new pedal or setting can always inspire an idea”. Edge cites “Mysterious Ways” (DigiTech Whammy pedal), “Where The Streets Have No Name”, “Beautiful Day” and “Bad”(his trademark delay) and “Elevation” (Ampeg Scrambler + Whammy) as just a few prime examples of where “the effects almost wrote the song.”

There is no better illustration of Edge’s point than “Elevation”. This BBC Imagine clip shows what Edge is actually fretting (answer = not much) and how his immense rig makes it sound. Some may scoff, but Edge is smiling because he did this and you didn’t. That’s genius.

Edge’s trusted guitar tech Dallas Schoo has been asked to divulge Edge’s FX rack secrets many times. “I regularly get calls from huge bands: “How does he get that tone? What are the pedals on that song?” I never give details, of course. But Edge never fails to surprise me. He’s all about sound. I’ve worked with many great guitar players, but Edge is the most unique. He really has something special.”

Edge, on his iconic Gibson Explorer…

Edge is gear nuts. He sometimes uses 18 different guitars to play 18 songs at a U2 show, but his first “proper” guitar, a 1976 Gibson Explorer, remains his most iconic. “I was in New York with my parents,” he told Guitar. “I went to Manny’s Music store, I think I was looking to buy a Les Paul or a Rickenbacker originally. But then I picked up this Gibson Explorer. It just spoke to me. Now, I knew that using this guitar could get an odd reaction as no-one was playing them back then. It’s an odd-looking thing. But it sounded just right for me, it had “my sound” in it. And it was only $450. I think it's the most distinctive of my guitars.”

Edge’s Explorer is all over early U2 records. While it was “rested” for much of the ‘80s and ‘90s, it was back with a vengeance on 2000’s All You Can’t Leave Behind, particularly return-to-form hit “Beautiful Day”.

Edge says, “It just has this unique tone. Adam [Clayton], in particular, was delighted to see it out again. He said, "This thing sounds like nothing else on earth!" It's a pretty special guitar.”

Here, Edge tells the tale of his Gibson Explorer and its comeback.

Edge, on why he rarely solos in a “traditional” manner…

“For the most part, I'm a minimalist at heart. If a song doesn't need a solo, I'm not going to force one into it,” he told Guitar Player. “It's always the music that dictates what I play. I never want to feel that I'm playing anything gratuitous. I get off on finding the perfect tone for the perfect part”.

Why Edge’s guitar influences are different to most…

Bono says, “Early on, Edge wasn’t at all taken with Rattle & Hum. Put it this way, Edge didn’t own a copy of Bob Dylan’s Blood On The Tracks. Edge’s [music] collection began in 1976 at the “New Beginning”. His interest was in European groups like Can, and back to Brian Eno.”

Edge himself told Rolling Stone, “If Bono had his way The Joshua Tree would have been even more American and bluesy. At first, we vehemently disagreed about what songs should be on that album. I was trying to pull it back to something less “roots”, something more experimental”.

What his bandmates say…

“"Edge, when I met him, always had this otherworldly quality, along with amused, detached cool”, bassist Adam Clayton told The Independent in 2005 “My impression now is exactly the same”.

Drummer Larry Mullen Jr. added, "I've learnt never to underestimate him. On any level. His dogged, relentless search for the perfect song, the perfect sound, the perfect idea. He possesses so many qualities I aspire to.”

Bono: “He’s a sonic genius. Simple as that.” In a written salute to his bandmate for The Independent newspaper, Bono said: "Beneath the stillness, the Zen-like mastery of arpeggios and perfectly-chosen crystal notes, there is a rage, an explosive side, as I've learnt on more than a few occasions. Never pick a fight with a man who earns his living through perfect hand-to-eye co-ordination."

U2 ‘vibemaster’, ‘guru’ and live DJ, BP Fallon: “Edge is the good-looking boffin with great cheekbones, eyes gentle and intense at the same time… and a mind that can find a bunch of wires and build a spaceship.”

Producer Daniel Lanois: “Edge is the master of the riff, one of the great musical forces. He's the driving wheel, pretty much in charge of what happens harmonically.”

U2 manager and ‘fifth member’ Paul McGuinness: “He’s an extremely intelligent man and a musical genius. He’s never encountered an instrument he couldn’t get something beautiful from, he’s a very gifted and versatile musician. I was impressed the first time I saw him play “Out Of Control” and he’s got even better since.”

And does Edge think he’s a great guitarist?

Edge’s own Zen-like analysis of himself is, “I play like me. I fit well in U2. A song like “Pride (In The Name Of Love)”, that’s Edge doing as Edge is”.

And finally, if you think Edge is simply too much about echo/delay, he has an answer for that too…

“Echo takes a guitar part somewhere else,” he told Guitar World. “It’s like what Andy Warhol did to art with his silk-screened prints of soup cans and photos. He played with art; he turned it upside down. The conventions that were supposedly sacred about imagery are the ones he threw away. I draw on that aesthetic decision.

“If I’m having trouble with a guitar part - not the playing of it, but the writing-  I’ll mess around with echo and other effects, just turn everything up and make it as crazy as can be, and it winds up taking me somewhere. I’ve found so many guitar parts from echo. It’s limitless.”