What is the “Plexi” Guitar Amp Sound?

• What is a Plexi?
• The Birth of Marshall
• Getting Louder
• Hot-Rodded Plexis
• Modern Alternatives
• Plexi Sound in a Box!
• F.A.Q
• Want to Learn More?

When I asked a colleague here at Andertons “what is the Plexi sound?”, he said “Van Halen I” — which brought up an interesting point. I think of the Plexi sound as Hendrix through his Fuzz Face or Clapton on the “Beano” album with John Mayall and The Bluesbreakers. So, what is the Plexi and is there a definitive Plexi sound?

Watch our video about our favourite guitar amplifiers that are inspired by the classic JTM sound – Click Here to find out!

What is a Plexi?

The Plexi gets its name from the early Marshall amps that used a plexiglass front panel during the ‘60s, before this was replaced by brushed metal in 1969. So really, when we talk about the Plexi, we mean early Marshall amps.

The Birth of Marshall

Jim Marshall was a drummer and London music store owner. The store built a reputation amongst guitarists such as Jimmy Page, Pete Townshend and Ritchie Blackmore, all looking to get their hands on rare Fender amps from across the pond.

In the early ’60s, Fender amps were expensive to import, so in 1962 Marshall decided to start building his own guitar amplifiers to replicate the Fender Tweed Bassman. However, due to the availability of components, he ended up making something that sounded quite different – The JTM45! This was the first Marshall amp, and one of the most iconic. It used KT66 power valves (or tubes, depending on your persuasion) compared to the 6L6 valves of the Bassman, and higher gain ECC83 preamp valves, that the 12AY7s of its American cousin.

These changes resulted in more amp distortion, which became an increasing trend in the early days of British Rock and Roll. These JTM45s got into the hands of Eric Clapton, Jimi Hendrix and Paul Kossoff, and created the famous “British Sound”.

Getting Louder

The Plexi sound is synonymous with incredible volume and crunchy overdrive, as guitarists of the ’60s cranked the sound to achieve more distortion. For me, the quintessential Plexi sound is a JMT45 turned up to 10, as heard from Clapton on the “Beano” album. (Rumour has it that you can switch a guitar amp up to 11, but we’ve never seen it.)

During the 1960s, Marshall switched to louder KT88 power valves as his amplifiers grew more powerful. Whilst at about 45 watts, the JTM45 was loud, in 1967 he introduced the 50 Watt and 100 Watt Superlead. It’s these 100W Superleads that gave The Who and Jimi Hendrix their sound.

By this point, Marshall was using EL34 power valves – these are the ones most commonly associated with Marshall amps. They could produce more volume and gave the amps a stronger mid-range character.

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Hot-Rodded Plexis

As rock music got heavier in the ’70s, guitarists started modifying (commonly known as hot-rodding) their Plexis for more gain (essentially, volume) – and this is a large part of the reason why the “Plexi sound” means different things to different people. This brings us back to Eddie Van Halen and his hot-rodded Marshall on Van Halen I. Moving on to the 1980s, one name stands out – José Arredondo – whose amp modifications for Steve Vai, James Hetfield, and Eddie Van Halen, made him a legend in the guitar world.

This progression eventually paved the way for the high-gain modern Marshall amps like the JCM800, but the lineage is all routed to those plexiglass front panel amps that Jim Marshall was making in the back of his music store in North West London in the early 1960s. Whether you’re a fan of the classic ‘60s Plexi sound, or the juiced up ‘70s hot-rodded Plexi sound, the aura around the Plexi has etched Marshall into Rock ‘n’ Roll legend.

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Modern Alternatives

Several contemporary companies offer their own take on the hot-rodded Plexi-style guitar amp, giving you a wide choice when it comes to achieving that classic sound. You should certainly check out EVH – a range designed by Eddie Van Halen himself. Other models to look out for include the hand-built Victory amps, and the excellent Friedman products.

Plexi Sound in a Box!

But what if you’re not playing at giant sold out arenas, and you have no use for a 100-watt Plexi? Or you simply don’t have the funds to shell out for a new amp? Well, you’re in luck. In recent years, pedal builders have looked to capture that distinctive tone in a compact stompbox format, so you can take that sound with you anywhere, at any volume.

From Tone City to Strymon, there’s a Plexi pedal for you. For classic low-to-mid gain Plexi sounds, try the JHS Charlie Brown. Or if you’re looking for the higher gain, hot-rodded Plexi sound, or for a more versatile Plexi pedal, check out the Tone City Golden Plexi, the Universal Audio UAFX Lion 68 Super Lead Amp Simulator Pedal or the Wampler Plexi Mini.

Hear the sounds of the Tone City Golden Plexi 2, or the NUX Plexi Crunch for yourself!

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F.A.Q

• What is a Plexi amplifier? The terms ‘Plexi’ or ‘Plexi style’ refer to amplifiers which deliver a classic ‘rock’ sound with high volume and distortion.
• What is ‘Plexi’ short for? Plexi is short for ‘plexiglass’ – a reference to the 1960s Marshall amps which had a plexiglass front.
• What is a hot-rodded amp? An amp which has been custom modified for higher volume and distortion.
• What is a stompbox? Small, portable units designed to modify your guitar’s sound. A stompbox differs from a guitar pedal in that it has a simple on/off switch.

Want to Learn More?

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