Legendary Tones Caswell 1987 Mod Plug-In High Gain Tube Modification Module - Reverse Wire

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Legendary Tones 1987 Caswell Mod Standard Edition - Reverse Wire Version

Caswell 1987 Mod – Bringing Back the Spirit of S.I.R. #39

In 1987, the sound of rock changed forever. It was raw, unapologetic, and drenched in attitude. Tim Caswell’s infamous #39 mod turned a standard Marshall into a snarling, harmonically rich beast, and with it provided a tone that fueled a generation of guitar heroes and defined an era when rock truly ruled the airwaves.

Now that legacy returns.

The Caswell 1987 Mod captures the heart and soul of that groundbreaking circuit with the aggressive gain structure, sensitivity, and harmonic fire that made #39 a legend. Built on the foundation of our acclaimed Hot Mod V2, the Caswell 1987 Mod refines the formula for today’s player while staying true to the original spirit of late-’80s excess and sonic dominance.

Expect explosive punch, glassy upper harmonics, and that unmistakable “LA Strip” grind that jumps out of the mix. Whether you’re chasing the tone of your idols or forging your own signature voice, the Caswell 1987 Mod delivers the elusive mix of clarity and chaos. It’s the sound of 1987, reborn.

Thump Switch

Engage the Thump switch and unleash a massive low-end response that hits like a freight train. It adds deep, percussive punch and body to your tone, giving palm-muted riffs and power chords that unmistakable ’80s arena impact.

Bite Switch

Flip the Bite switch to ignite upper-midrange harmonics and enhance note definition and presence. This feature adds edge and articulation, letting solos cut through with searing clarity and that classic LA studio sizzle.

Drive Control

The Drive pot gives you total command of the added gain stage. From tight, classic crunch to full-blown, saturated lead tones, the Drive control lets you dial in your perfect level of aggression and sustain.

Pure attitude, no compromises. The standard Caswell 1987 Mod brings the raw, high-voltage aggression and spirit of the legendary #39 circuit straight to your amp. Built with premium components and tuned for punch, clarity, and harmonic richness: this is the sound of 1987 reborn and ready to roar

***There are two different models currently available.  This listing is for the Caswell Mod Reverse Wired:

For original JMP and JCM 800 series 2203/2204/1959/1987. The standard wired model also works for the early reissue 1959/1987 models without the factory-installed effects loop. Choose the standard wire option if you use the new Marshall studio series SC20H/SV20H heads as well!

Will my Caswell Mod work in my amp?

HOT MOD V2/LYNCH/CASWELL MOD REVERSE WIRED COMPATIBILITY LIST:

JCM 800 800 2203X reissue (all years), 2203ZW (Zakk Wylde signature)

1987X (model year 2003+ w/Marshall added effects loop)

1959SLP (w/Marshall added effects loop)

1959RR (Randy Rhoads Signature)

JTM 45 reissue model 2245, Bluesbreaker reissue combo 1962

Friedman Amps:
Runt 50 (V3), Runt 20** (V2), JEL-20 and JJ Jr.**(V2) are each compatible with the reverse-wire version of the Mods (use in V3 position of Runt 50). 

**NOTE 2: While the Runt 20 (reverse wire), JEL-20 and JJ Jr. (reverse wire) models are sonically compatible with the Mod, the head enclosures are too shallow and don’t have enough depth to fit the Mod chassis without FIRST removing the amp chassis from the head box. So if you would like to use the HMV2E with these amps, you first need to remove the chassis bolts, slide out the chassis, install the mod, and then slide the chassis back into its head box and retighten the chassis bolts.

Popular amps that the Mods DO NOT WORK with include: Marshall Silver Jubilee series, Marshall Origin series, Marshall Vintage Modern Series, Mesa Boogie Mark series amps, Bugera 1960, and Hiwatt DR series.

Some History

Back in the late 1980s, Mike Soldano of Soldano Custom Amplification released his original Hot Mod, a design based around use of rare 6C10 (and then later 6K11) tubes. These tube types added more gain much the same way that the HOT MOD V2 EVO and Lynch Mod do, but they had limitations. The tubes were long out of production, getting expensive to find, and often would become microphonic and therefore limited in capability. The original Soldano Hot Mod had lots of gain and delivered on its promise, but it was ultimately taken out of production primarily due to the challenges with finding consistent and quiet tubes.

Still, the original Hot Mod was the inspiration for the HOT MOD V2 EVO and Lynch Mod, which function in much the same way as the original, but now have additional circuitry that further stabilize the design, provide more clarity, and deliver a wider, more controllable range of gain on the preamp control of the amp rather than coming onto high-gain territory too quickly. And of course the HMV2E and Lynch Mod now also uses a 12AX7 and 12AT7 tubes that are commonly available.