For those who are interested, here's the truth about Peter Green's (and, later, Gary Moore's) famous 1958 Les Paul's strange tone.
An electric guitar has pickups, to convert the string's vibration into an electrical signal which can then be amplified. A pickup is basically a coil (or coils) of wire and a permanent magnet. As Michael Faraday taught us, when a steel or iron object is inserted into a magnetic field, it creates a small electrical current.
As usual, there are several schools of thought about how best to do this with guitars. Fender (makers of some of the most iconic guitars ever) tended to favour pickups with a single coil of wire, and this produces a very clear, bright and almost piano like tone.
The only problem with single coil pickups was that they often produce a 50 to 60 hertz hum.
Gibson, makers of numerous iconic guitars, not least the Les Paul, came up with a pickup with 2 sets of coils and a magnet. These are known as twin coils, and, because they cancelled out the hum, they became more famous as "Humbuckers". Humbuckers are typically lower output than single coils, but because they effectively read more of the string's length (they have a much wider magnetic field), they have a "fatter", often darker tone.
You may not think it, but the wood an electric guitar is made from is important. An electric guitar is nothing more than a plank with 2 anchors for the strings at each end. The more rigid those anchors and the more resonant the wood, the longer the string can vibrate and the better the tone. Different manufacturers have their own theories, but the classic Les Paul was a solid lump of mahogany and with a relatively thin maple "cap" on the top of the guitar body. Mahogany is very resonant, but maple is very hard and heavy, this adds a little brightness to the tone. It also explains why most Les Paul players end up at hunchbacks. It's a very heavy guitar.
So, Peter Green's 1958 Les Paul was already some 9 years old when he bought it. It had been worked pretty hard and was knocked about. Most guitars have 2 or more pickups: where they are placed makes a huge difference. Closer to the neck gives a more rounded tone, towards the rear of the guitar- the bridge- gives a brighter, more treble tone. Watch that Gary Moore and B.B. King clip again and see Gary switching pickups. The pickup switch on a Les Paul is right at the top as you're holding it, on the above the neck pickup.
Anyhow, Peter Green's guitar's front pickup was constantly playing up. Most likely the wires were breaking down. He apparently took it for repair to a man who was far more familiar with repairing Fender, single coil, pickups. This bloke completely re-wired the pickup, but used the wrong wire (he used far thicker "formvar" wire as used on Fenders) and he rotated the wire the wrong way. This made the front pickup "out of phase".
However, this is apparently only when both pickups are used together! The volume levels of both have to be roughly equal. When this occurs, we hear that magical, nasal "squawk" you can briefly hear at 6:15 on the "Thrill has gone" clip above.
Otherwise, the front pickup sounds normal.
There are lots of silly stories in the 'net about flipping the front magnet, but never have I heard of anyone actually doing it. Everybody swears that's how it's done, but nobody ever does it to find out. Not least because if you took apart a proper late 50's PAF Humbucker, you'd be hung, drawn and quartered and buried in several unmarked graves within the hour
Guitarists are weird. They almost all really, really, want guitars that are older than them
A friend of mine recently bought a very good condition 1959 Les Paul from America. He paid.........the price of a second hand Lamborghini. He then flew over to the USA personally and bought a ticket
for the guitar to bring it back next to him, rather than risk it through luggage.
His dumb arse is dead if ever his wife finds out, but since she has a thing about £1000 handbags, he has quite a lever on her
I own a set of absolutely authentic PAF pickups (PAF actually means "Patent Applied For" !) with the Peter Green modification. The attention to detail in their manufacture is stunning.